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Cochrane Database of Systematic Reviews Review - Intervention

Cognitive training for people with mild to moderate dementia

Authors' declarations of interest

Version published: 25 March 2019 Version history

https://doi.org/10.1002/14651858.CD013069.pub2
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Background

Cognitive impairment, a defining feature of dementia, plays an important role in the compromised functional independence that characterises the condition. Cognitive training (CT) is an approach that uses guided practice on structured tasks with the direct aim of improving or maintaining cognitive abilities.

Objectives

• To assess effects of CT on cognitive and non‐cognitive outcomes for people with mild to moderate dementia and their caregivers.

• To compare effects of CT with those of other non‐pharmacological interventions, including cognitive stimulation or rehabilitation, for people with mild to moderate dementia and their caregivers.

• To identify and explore factors related to intervention and trial design that may be associated with the efficacy of CT for people with mild to moderate dementia and their caregivers.

Search methods

We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group Specialised Register, on 5 July 2018. ALOIS contains records of clinical trials identified through monthly searches of several major healthcare databases and numerous trial registries and grey literature sources. In addition to this, we searched MEDLINE, Embase, PsycINFO, CINAHL, LILACS, Web of Science Core Collection, ClinicalTrials.gov, and the World Health Organization's trials portal, ICTRP, to ensure that searches were comprehensive and up‐to‐date.

Selection criteria

We included randomised controlled trials (RCTs) that described interventions for people with mild to moderate dementia and compared CT versus a control or alternative intervention.

Data collection and analysis

We extracted relevant data from published manuscripts and through contact with trial authors if required. We assessed risk of bias using the Cochrane 'Risk of bias' tool. We divided comparison conditions into active or passive control conditions and alternative treatments. We used a large number of measures and data to evaluate 19 outcomes at end of treatment, as well as 16 outcomes at follow‐up in the medium term; we pooled this information in meta‐analyses. We calculated pooled estimates of treatment effect using a random‐effects model, and we estimated statistical heterogeneity using a standard Chi² statistic. We graded the evidence using GradePro.

Main results

The 33 included trials were published between 1988 and 2018 and were conducted in 12 countries; most were unregistered, parallel‐group, single‐site RCTs, with samples ranging from 12 to 653 participants. Interventions were between two and 104 weeks long. We classified most experimental interventions as 'straight CT', but we classified some as 'augmented CT', and about two‐thirds as multi‐domain interventions. Researchers investigated 18 passive and 13 active control conditions, along with 15 alternative treatment conditions, including occupational therapy, mindfulness, reminiscence therapy, and others.

The methodological quality of studies varied, but we rated nearly all studies as having high or unclear risk of selection bias due to lack of allocation concealment, and high or unclear risk of performance bias due to lack of blinding of participants and personnel.

We used data from 32 studies in the meta‐analysis of at least one outcome. Relative to a control condition, we found moderate‐quality evidence showing a small to moderate effect of CT on our first primary outcome, composite measure of global cognition at end of treatment (standardised mean difference (SMD) 0.42, 95% confidence interval (CI) 0.23 to 0.62), and high‐quality evidence showing a moderate effect on the secondary outcome of verbal semantic fluency (SMD 0.52, 95% CI 0.23 to 0.81) at end of treatment, with these gains retained in the medium term (3 to 12 months post treatment). In relation to many other outcomes, including our second primary outcome of clinical disease severity in the medium term, the quality of evidence was very low, so we were unable to determine whether CT was associated with any meaningful gains.

When compared with an alternative treatment, we found that CT may have little to no effect on our first primary outcome of global cognition at end of treatment (SMD 0.21, 95% CI ‐0.23 to 0.64), but the quality of evidence was low. No evidence was available to assess our second primary outcome of clinical disease severity in the medium term. We found moderate‐quality evidence showing that CT was associated with improved mood of the caregiver at end of treatment, but this was based on a single trial. The quality of evidence in relation to many other outcomes at end of treatment and in the medium term was too low for us to determine whether CT was associated with any gains, but we are moderately confident that CT did not lead to any gains in mood, behavioural and psychological symptoms, or capacity to perform activities of daily living.

Authors' conclusions

Relative to a control intervention, but not to a variety of alternative treatments, CT is probably associated with small to moderate positive effects on global cognition and verbal semantic fluency at end of treatment, and these benefits appear to be maintained in the medium term. Our certainty in relation to many of these findings is low or very low. Future studies should take stronger measures to mitigate well‐established risks of bias, and should provide long‐term follow‐up to improve our understanding of the extent to which observed gains are retained. Future trials should also focus on direct comparison of CT versus alternative treatments rather than passive or active control conditions.

PICOs

Population
Intervention
Comparison
Outcome

The PICO model is widely used and taught in evidence-based health care as a strategy for formulating questions and search strategies and for characterizing clinical studies or meta-analyses. PICO stands for four different potential components of a clinical question: Patient, Population or Problem; Intervention; Comparison; Outcome.

See more on using PICO in the Cochrane Handbook.

Cognitive training for people with mild to moderate dementia

Background

Dementia due to Alzheimer’s and other diseases is a leading cause of disability and an enormous health and societal problem. More than 40 million people in the world currently live with dementia, and this number is expected to increase to more than 115 million by the year 2050. Effective treatments to reduce the burden of dementia are urgently needed. Cognitive training (CT) is a non‐pharmacological form of treatment that focuses on guided practice on tasks that target specific cognitive functions, such as memory, attention, or problem‐solving. Whether CT can help people with mild to moderate dementia maintain or improve their thinking, well‐being, and general functioning remains unclear.

Main findings

We analysed data from 33 studies of CT that included a total of approximately 2000 participants and were conducted in 12 countries. We found that, compared with receiving usual treatment or engaging in non‐specific activities, people completing CT may show some benefits in overall cognition, as well as in more specific cognitive abilities such as verbal fluency, and that improvements may last for at least a few months. We did not find any evidence that participating in CT was associated with increased burden for participants. However, we also found no evidence that CT was better than participating in other active treatments.

Limitations of this review

The quality of the studies we reviewed varied but overall was not very high, so our certainty in some of these findings is low. Future studies should continue improving on quality, should continue comparing CT with other treatments, and should follow participants for a longer period to understand whether observed benefits for cognition last beyond the short or medium term.

Authors' conclusions

available in

Implications for practice

For people with mild to moderate dementia, relative to usual treatment or non‐specific activities, standardised cognitive training (CT) may lead to at least small improvements in overall cognition at end of treatment, and these improvements may be sustained over the medium term after treatment cessation (between 3 and 12 months). Benefits in the short and medium term may also be observed in more specific areas of cognition, such as verbal fluency. The evidence regarding gains associated with CT in clinical disease progression, mood, activities of daily living, or caregiver burden relative to usual or non‐specific activities is not clear. No evidence suggests that CT is associated with any harm to the person with dementia in terms of negative impact on important outcomes such as mood and well‐being, accelerated cognitive or functional decline, or worsening caregiver burden. For many important outcomes, particularly in the medium term, the overall quality of evidence was low, so further publication of high‐quality evidence may lead to changes in observed effects. It is important to note that no evidence suggests that CT provides any benefit when compared to alternative treatments, such as cognitive stimulation therapy or physical exercise. The decision of whether a person with dementia should commence a formal cognitive training intervention to improve his or her cognition should be made with consideration of the balance of potentially modest effects on cognition in the short to medium term and any possible contraindications related to personal values and preferences, available resources in the person's locality, and other possible trade‐offs. Clinicians should work together with the person with dementia and his or her significant others to carefully balance the various considerations, including the specific context of the patient, in deciding whether or not a formal CT intervention should be started. Although it is beyond the scope of this review to discuss all relevant health policy‐related considerations, evidence from the current review should be interpreted within the broader context of evidence for treatments, including pharmacological treatments, for people with mild to moderate dementia. In particular, observed effects of CT on global cognition at end of treatment may be comparable or stronger than effects on cognition associated with approved medications (Birks 2015; Birks 2018), but without some of the adverse effects associated with these medications. Further work is required to better understand cost‐effectiveness associated with cognitive training for people with mild to moderate dementia, to better inform health‐related policy.

Implications for research

A relatively large body of work on the effects of CT for various outcomes among people with dementia is now available; unfortunately, despite improvement in some areas, the quality of these studies often is still low, leading to low confidence in the accuracy of some of these review findings. To increase our confidence in the findings of the current review, it is important that any further studies of CT for people with dementia are conducted with rigorous methodological standards, to ensure that risks of bias are adequately mitigated. In particular, trial registration and separate publication of detailed trial protocols including plans for analyses and dissemination are critical for reducing risk of bias due to selective reporting, and for identifying issues related to trial fidelity. It is recommended that ethical review boards ensure trials are registered before they give final approval for recruitment to commence, and that publication of a trial protocol is specified as a milestone when funding applications are made, and during ethical approval of the application. It is also important that key design features are adequately implemented and clearly reported in published reports, particularly around methods of randomisation, allocation concealment, and masking of participants and personnel. Although masking is not possible in behavioural interventions involving a passive or 'treatment as usual' comparison condition, it can be achieved in studies using active control conditions or alternative treatments. Our findings do not provide strong support for the use of active ("placebo") control conditions as far as effects of the interventions are concerned. However, more studies in which CT is compared with other specific interventions are needed to build a stronger evidence base that would allow consumers and decision‐makers to make more informed choices between alternative treatments that may offer some benefit to people with dementia. To reduce some of the statistical heterogeneity observed in these studies, it is important that, wherever possible, evaluation of outcomes is done on the basis of published measures with established psychometric properties. It is important that future studies are better designed to explore dose‐response‐related issues, as well as issues related to maintenance or waning of treatment effects. Understanding of the long‐term impact of CT on clinically relevant outcomes, including admission to residential care, quality of life, and caregiver burden, remains and important goal of future research. Several recent publications have provided further important advice and minimum standards for the conduct of cognitive training research (e.g. Simons 2016), and an international working party including several experts in this area is currently working to develop research guidelines in this area (Bahar‐Fuchs 2014).

Summary of findings

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Summary of findings for the main comparison. Cognitive training compared to control immediately post intervention for people with mild to moderate dementia

Cognitive training compared to control immediately post intervention for people with mild to moderate dementia

Patient or population: people with mild to moderate dementia
Setting: Community dwelling or in residential care
Intervention: cognitive training
Comparison: control immediately post intervention

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No. of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with control immediately post intervention

Risk with cognitive training

Change in a global measure of cognition (composite)

Mean change in a global measure of cognition (composite) was 0

SMD 0.42 higher
(0.23 higher to 0.62 higher)

‐

1389
(27 RCTs)

⊕⊕⊕⊝
MODERATEa

Cognitive training probably has a modest effect on global cognition (based on a composite score)

Change in a global measure of cognition

Mean change in a global measure of cognition was 0

SMD 0.65 higher
(0.26 higher to 1.05 higher)

‐

1288
(20 RCTs)

⊕⊕⊝⊝
LOWb

Cognitive training may have a moderate effect on performance in global cognition (based on a screening measure).

Change in delayed memory

Mean change in delayed memory was 0

SMD 0.81 higher
(0.29 higher to 1.32 higher)

‐

543
(11 RCTs)

⊕⊝⊝⊝
VERY LOWb,c

We are unable to determine whether there is any effect on delayed memory due to the very low quality of evidence

Change in participants' mood

Mean change in participants' mood was 0

SMD 0.72 higher
(0.1 lower to 1.54 higher)

‐

577
(8 RCTs)

⊕⊝⊝⊝
VERY LOWb,d

We are unable to determine whether there is any effect on participants' mood due to the very low quality of evidence

Change in capacity for activities of daily living

Mean change in capacity for activities of daily living was 0 SD

SMD 0.12 SD higher
(0.11 lower to 0.35 higher)

‐

687
(10 RCTs)

⊕⊕⊝⊝
LOWd

Cognitive training may not have an effect on capacity for activities of daily living

Participant burden (retention rates)

Study population

OR 0.73
(0.37 to 1.43)

1282
(17 RCTs)

⊕⊕⊝⊝
LOWe

Cognitive training may not be associated with an increase in participant burden as reflected in retention rates

908 per 1000

878 per 1000
(784 to 934)

Change in mood and well‐being (caregiver)

Mean change in mood and well‐being (caregiver) was 0

SMD 0.98 higher
(0.27 higher to 1.68 higher)

‐

36
(1 RCT)

⊕⊕⊕⊝
MODERATEf,g

Cognitive training probably has a large effect on mood and well‐being in the caregiver

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; OR: odds ratio; RCT: randomised controlled trial; SMD: standardised mean difference.

GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

aInconsistency: downgraded 1 point for serious concerns regarding heterogeneity in effect size, which is moderate and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

bInconsistency: downgraded 2 points for very serious concerns regarding heterogeneity in effect size, which is relatively large and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

cPublication bias: downgraded 1 point for strongly suspected publication bias based on visual inspection of the funnel plot, raising the possibility that small negative studies may remain unpublished.

dImprecision: downgraded 1 point for serious concerns related to imprecision because the confidence interval crosses the no treatment threshold.

eImprecision: downgraded 2 points for very serious concerns related to imprecision because the confidence interval includes positive effect, negligible effect, and effect in the direction of the control group.

fRisk of bias: outcome estimation is based on a single study with several limitations related to unclear or high risk of bias in several domains.

gImprecision: downgraded 1 point for serious concerns related to imprecision because the analysis is based on fewer than 400 participants; however the confidence interval does not cross the no effect threshold.

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Summary of findings 2. Cognitive training compared to control in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

Cognitive training compared to control in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

Patient or population: people with mild to moderate dementia
Setting: Community dwelling or in residential care
Intervention: cognitive training
Comparison: control in the medium term (3 to 12 months post intervention)

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No. of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with control in the medium term (3 to 12 months post intervention)

Risk with cognitive training

Change in a global measure of cognition (composite)

Mean change in a global measure of cognition (composite) was set at 0 SDs

SMD 0.65 higher
(0.11 higher to 1.2 higher)

‐

387
(8 RCTs)

⊕⊝⊝⊝
VERY LOWa,b,c

We are unable to determine whether there is any effect on global cognition (composite) due to the very low quality of evidence

Change on global cognition (screening) (Global cog)

Mean change in global cognition (screening) was set at 0 SDs

SMD 1.33 higher
(0.31 higher to 2.34 higher)

‐

387
(6 RCTs)

⊕⊝⊝⊝
VERY LOWa,d,e

We are unable to determine whether there is any effect on performance in global cognition due to the very low quality of evidence

Change in disease progression

Mean change in disease progression was set at 0 SDs

SMD 0.55 higher
(0.12 higher to 0.98 higher)

‐

98
(3 RCTs)

⊕⊝⊝⊝
VERY LOWa,c

We are unable to determine whether CT slows down disease progression due to the very low quality of evidence

Change in delayed memory

Mean change in delayed memory was set at 0 SDs

SMD 0.97 SD higher
(0.02 higher to 1.92 higher)

‐

253
(4 RCTs)

⊕⊝⊝⊝
VERY LOWa,c,d

We are unable to determine whether there is any effect on performance in delayed memory due to the very low quality of evidence

Change in capacity for activities of daily living

Mean change in capacity for activities of daily living was set at 0 SDs

SMD 0.22 higher
(0.5 lower to 0.94 higher)

‐

64
(3 RCTs)

⊕⊕⊝⊝
LOWc

Cognitive training may not have an effect on capacity for activities of daily living

Change in participants' mood

Mean change in participants' mood was set at 0 SDs

SMD 0.21 higher
(0.54 lower to 0.96 higher)

‐

30
(2 RCTs)

⊕⊕⊝⊝
LOWc

Cognitive training may not have an effect on participants' mood

Change in mood and well‐being (caregiver)

‐

See comment

‐

(0 studies)

‐

No studies have evaluated this outcome in the intermediate term

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; CT: cognitive training; OR: odds ratio; RCT: randomised controlled trial; SD: standard deviation; SMD: standardised mean difference.

GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

aRisk of bias: downgraded 2 points for very serious concerns related to risk of bias: removal of high‐risk studies leads to reasonably large changes in the effect estimate.

bInconsistency: downgraded 1 point for serious concerns regarding heterogeneity in effect size, which is large and statistically significant. However, heterogeneity seems to be partially explained by investigated effect moderators.

cImprecision: downgraded 2 points for very serious concerns related to imprecision because the analysis is based on fewer than 400 participants, and the confidence interval crosses the no effect threshold.

dInconsistency: downgraded 2 points for very serious concerns regarding heterogeneity in effect size, which is relatively large and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

eImprecision: downgraded 1 point for serious concerns related to imprecision because the analysis is based on fewer than 400 participants; however the confidence interval does not cross the no effect threshold.

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Summary of findings 3. Cognitive training compared to alternative treatment immediately post intervention for people with mild to moderate dementia

Cognitive training compared to alternative treatment immediately post intervention for people with mild to moderate dementia

Patient or population: people with mild to moderate dementia
Setting: Community dwelling or in residential care
Intervention: cognitive training
Comparison: alternative treatment immediately post intervention

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No. of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with alternative treatment immediately post intervention

Risk with cognitive training

Change in a global measure of cognition (composite)

Mean change in a global measure of cognition (composite) was 0 SD

SMD 0.21 SD higher
(0.23 lower to 0.64 higher)

‐

769
(7 RCTs)

⊕⊕⊝⊝
LOWa

Cognitive training may not have an effect on global cognition

Change in a global measure of cognition

Mean change in a global measure of cognition was 0

SMD 0.16 higher
(0.28 lower to 0.6 higher)

‐

724
(7 RCTs)

⊕⊝⊝⊝
VERY LOWa,b

We are unable to determine whether there is any effect on global cognition (as measured by a screening tool) due to very low quality of evidence

Change in delayed memory

Mean change in delayed memory was 0

SMD 0.71 higher
(0.33 lower to 1.75 higher)

‐

147
(3 RCTs)

⊕⊝⊝⊝
VERY LOWc,d

We are unable to determine whether there is any effect on performance in delayed memory due to very low quality of the evidence

Change in participants' mood

Mean change in participants' mood was 0

SMD 0.11 lower
(0.29 lower to 0.07 higher)

‐

543
(3 RCTs)

⊕⊕⊕⊝
MODERATEe

Cognitive training probably has no effect on participants' mood

Change in capacity for activities of daily living

Mean change in capacity for activities of daily living was 0

SMD 0.25 lower
(0.43 lower to 0.07 lower)

‐

525
(3 RCTs)

⊕⊕⊕⊝
MODERATEe

Cognitive training probably has no effect on capacity for activities of daily living

Participant burden (retention rates)

Study population

OR 0.78
(0.24 to 2.57)

639
(4 RCTs)

⊕⊝⊝⊝
VERY LOWa,b

We are unable to determine whether cognitive training increases participant burden (as measured by retention rates)

773 per 1000

727 per 1000
(450 to 898)

Change in mood and well‐being (caregiver)

Mean change in mood and well‐being (caregiver) was 0

SMD 1.5 higher
(0.96 higher to 2.04 higher)

‐

88
(1 RCT)

⊕⊕⊕⊝
MODERATEf

Cognitive training probably has a large effect on mood and well‐being in the caregiver

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; OR: odds ratio; RCT: randomised controlled trial; SD: standard deviation; SMD: standardised mean difference.

GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

aImprecision: downgraded 2 points for very serious concerns related to imprecision because the confidence interval includes positive effect, negligible effect, and effect in the direction of the control group.

bInconsistency: downgraded 1 point for serious concerns regarding heterogeneity in effect size, which is moderate and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

cInconsistency: downgraded 2 points for very serious concerns regarding heterogeneity in effect size, which is relatively large and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

dImprecision: downgraded 2 points for very serious concerns related to imprecision because the analysis is based on fewer than 400 participants, and the confidence interval crosses the no effect threshold.

eImprecision: downgraded 1 point for serious concerns related to imprecision because the sample size includes fewer than 400 participants.

Open in table viewer
Summary of findings 4. Cognitive training compared to alternative treatment in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

Cognitive training compared to alternative treatment in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

Patient or population: people with mild to moderate dementia
Setting: Community dwelling or in residential care
Intervention: cognitive training
Comparison: alternative treatment in the medium term (3 to 12 months post intervention)

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No. of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with alternative treatment in the medium term (3 to 12 months post intervention)

Risk with cognitive training

Change in a global measure of cognition (composite)

Mean change in a global measure of cognition (composite) was set at 0 SDs

SMD 1.31 SD higher
(1.03 lower to 3.65 higher)

‐

73
(2 RCTs)

⊕⊝⊝⊝
VERY LOW

We are unable to determine whether there is any effect on global cognition (composite) due to very low quality of the evidence

Change in a global measure of cognition

Mean change in a global measure of cognition was set at 0 SDs

SMD 3.2 higher
(2.89 lower to 9.29 higher)

‐

73
(2 RCTs)

⊕⊝⊝⊝
VERY LOW

We are unable to determine whether there is any effect on performance in a screening measure of global cognition due to very low quality of the evidence

Change in disease progression

‐

See comment

‐

(0 studies)

‐

None of the included studies have evaluated this outcome

Change in delayed memory

Mean change in delayed memory was set at 0 SDs

SMD 3.13 higher
(3.57 lower to 9.83 higher)

‐

73
(2 RCTs)

⊕⊝⊝⊝
VERY LOW

We are unable to determine whether there is any effect on performance in delayed memory due to very low quality of the evidence

Change in participants' mood

Mean change in participants' mood was set at 0 SDs

SMD 0.66 lower
(1.35 lower to 0.02 higher)

‐

39
(1 RCT)

⊕⊕⊝⊝
LOWa

Cognitive training may not have an effect on a participants' mood

Change in capacity for activities of daily living

‐

See comment

‐

(0 studies)

‐

None of the included studies have evaluated this outcome

Change in mood and well‐being (caregiver)

‐

See comment

‐

(0 studies)

‐

None of the included studies have evaluated this outcome

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; OR: odds ratio; RCT: randomised controlled trial; SD: standard deviation; SMD: standardised mean difference.

GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

aImprecision: downgraded 2 points for very serious concerns related to imprecision because the confidence interval includes positive effect, negligible effect, and effect in the direction of the control group.

Background

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Description of the condition

Dementia is a clinical syndrome in which functional independence is compromised due to intellectual and cognitive impairment (mostly of gradual onset). Dementia typically is caused by age‐related pathophysiological processes. Alzheimer's disease (AD) and mixed AD and cerebrovascular disease are the most common causes of dementia in older people (Alzheimer's Association 2018). Other common causes include Lewy body pathology (in dementia with Lewy bodies (DLB) and in Parkinson’s disease dementia (PDD)) and frontotemporal lobar degeneration (in the frontotemporal dementias (FTDs), there are numerous other, rarer causes) (Alzheimer's Disease International 2009).

Dementia due to most neurodegenerative conditions is usually associated with aggregates of folded or misfolded proteins (Villemagne 2018). In the case of dementia due to AD, this includes aggregates of the Aβ protein that form into plaques in the space between neurons, as well as aggregates of misfolded tau protein that form neurofibrillary tangles inside neurons. Other protein aggregates are implicated in other neurodegenerative diseases (e.g. TDP‐43 in FTD, alpha‐synuclein protein aggregates in dementia with Lewy bodies). Aggregated proteinopathies usually spread in a predictable and well‐described manner through cortical and subcortical regions (Braak & Braak 2012). In the case of most dementia aetiologies, the pathophysiological chain of events commences years or even decades before the onset of obvious clinical symptoms, at which stage individuals are increasingly brought to clinical attention (Alzheimer's Association 2018).

Regardless of cause, dementia usually has an insidious onset and a progressive course (although in some cases, e.g. vascular cognitive impairment, a more rapid onset may be seen) (Wilson 2012). Although the clinical presentation at early or mild stages may vary according to underlying disease aetiology, global cognitive impairment, changes in personality and behaviour, and compromised functional independence are common characteristics with clinical progression. Cognitive impairment (in the case of AD and vascular disease) and behavioural, personality, or language changes (in the case of frontotemporal neurodegeneration) are typically present well before a clinical diagnosis is made, but at early stages, these can be difficult to differentiate from common age‐related changes, or from symptoms associated with common psychiatric conditions (e.g. depression) ‐ a factor that often leads to delays in bringing the situation to medical attention. During the pre‐dementia phase, individuals usually present with mild cognitive impairment during a period in which cognitive impairment can be detected on formal examination (Albert 2011; Petersen 2004), but the individual usually shows no, or only minimal, impairment in ability to carry out most activities of daily living. In mild to moderate stages of dementia, cognitive impairment becomes more profound and widespread, functional disability becomes increasingly evident ‐ particularly in relation to more complex activities ‐ and caregiver burden tends to significantly increase (Berger 2005; Gaugler 2000). In more advanced stages of dementia, most cognitive and functional abilities are profoundly impaired, and behavioural changes such as apathy, depression, aggression, and agitation are frequently observed (Förstl 1999).

Despite some overlap, the cognitive symptom signature that characterises the different disease aetiologies that tend to develop into dementia can often be distinguished, at least at early stages. In the case of dementia due to AD, the earliest cognitive signs on formal neuropsychological examination are almost invariably related to episodic memory function. Within the memory domain, the most striking deficits are usually observed in measures of new learning and delayed recall ‐ deficits that precede the diagnosis of AD by several years (Weintraub 2012). Once deficits in measures of learning and memory have developed, individuals often show increasing difficulty performing tasks related to semantic memory, language, executive functions, and visuospatial/constructional abilities. In dementia with Lewy bodies, early cognitive impairments are more likely to involve striking visuospatial deficits, fluctuating attention, and reduced working memory capacity, along with the development of vivid hallucinations. In dementias related to frontotemporal lobar degeneration, early symptoms may be predominantly behavioural and may be related to social cognition in behavioural‐variant FTD, or in temporal subtypes may involve predominantly language skills and verbal expression (Weintraub 2012). Although impaired performance on measures of episodic memory is central to vascular dementia, people with this condition typically display a more striking deficit on executive and attention tasks, as well as on measures of semantic knowledge and visuospatial function (Graham 2004).

Dementia is highly prevalent in older people, is a leading cause of disability worldwide, and is associated with enormous financial, emotional, and societal burden (Wimo 2017), making research in this area a global priority (World Health Organization 2012). Despite years of research and numerous clinical trials, no cure is yet available for any of the irreversible causes of dementia. Cholinesterase inhibitors remain the primary pharmacological treatment for cognitive symptoms in AD and related dementias; however, the effects of these drugs are not universal and are always temporary (Birks 2006). A range of non‐pharmacological interventions (NPIs) that target different aspects of the clinical syndrome, associated disability, and caregiver burden are available (for a comprehensive systematic review, see Olazaran 2010). NPIs generally are not disease‐specific and do not directly engage underlying biological targets; they are therefore not 'disease‐modifying'. On the other hand, NPIs are more likely to target a broader spectrum of clinically meaningful outcomes and are less likely to cause adverse reactions. Within the broad category of NPIs, cognition‐oriented treatments, particularly CT, have been a topic of much interest among researchers, clinicians, and the general public.

Description of the intervention

'Cognition‐oriented treatments' (COTs), referred to previously as 'cognition‐focused interventions' (Clare 2002; Clare 2004), is an umbrella term referring to a group of NPIs in which a range of techniques are applied to engage thinking and cognition with various degrees of breadth and specificity. Unlike NPIs, which are primarily oriented towards outcomes that are behavioural (e.g. wandering), emotional (e.g. anxiety), or physical (e.g. sedentary lifestyle), in COTs, the goals include improving or maintaining cognitive processes or addressing the impact of impairment in cognitive processes on associated functional ability in daily life (Bahar‐Fuchs 2013; Clare 2004). CT, sometimes described in the literature as 'brain training', 'retraining', or 'remediation', typically involves guided practice of a set of structured ‐ usually standardised ‐ tasks, designed to train individuals on relatively well‐defined cognitive processes and abilities such as speed of information processing, attention, memory, or problem‐solving (Bahar‐Fuchs 2013; Mowszowski 2010). Other COTs described in the literature include cognitive stimulation therapy (CST) and cognitive rehabilitation (CR); these approaches are regarded as distinct in terms of their underlying theoretical assumptions and core elements, as well as the contexts or populations in which they have been traditionally applied, but it is acknowledged that some overlap exists, and that differentiating between these approaches is not always straightforward (Bahar‐Fuchs 2013; Gates 2014). Indeed, these terms have been and continue to be applied somewhat interchangeably in the literature (e.g. Fernandez‐Prado 2012; Giordano 2010), despite the availability of broad definitions and descriptions of these distinct forms of intervention (Bahar‐Fuchs 2013; Clare 2004; Woods 2012). Table 1 (below) summarises key defining features and common properties of these approaches. Cognitive stimulation is the focus of a separate Cochrane Review, which concluded that general cognitive stimulation consistently produces improvements in general cognition and, in some cases, in self‐reported quality of life and well‐being, primarily for people with mild to moderate dementia (Woods 2012). Cognitive rehabilitation, which is an inherently individualised approach emphasising collaborative goal‐setting and a functional orientation (Bahar‐Fuchs 2016; Clare 2001), has been considered alongside CT in previous versions of this Cochrane Review (Bahar‐Fuchs 2013; Clare 2004); however, as the body of evidence for this approach has increased in recent years, and as it involves different methods and targets different outcomes, cognitive rehabilitation will be considered in a separate Cochrane Review, and the current review accordingly will focus only on CT.

Cognitive training

Cognitive training (CT) is historically couched within the broader field of neuropsychological rehabilitation of individuals with brain injury and neurological diseases, with efforts to systematically retrain specific cognitive functions originally described by clinical researchers such as Leonard Diller and Yehuda Ben‐Yishay in their pioneering work with victims of stroke and head trauma throughout the 1970s (Ben‐Yishay 1978; Diller 1974). In the early 1980s, the principles of CT began to be applied in cognitively healthy older adults with subjective cognitive complaints (e.g. Zarit, 1981); however it was not until the late 1980s that CT was first attempted with people with dementia (e.g. Beck 1988). A central assumption underlying CT is that practice has the potential to improve or at least maintain functioning in the given cognitive domain. A further important assumption is that any effects of practice will generalise beyond the immediate training context. In other words, improved performance on a given task should lead to improved performance on other, related tasks that depend on the same cognitive process or ability. Although this last assumption often has not been supported by the evidence (Owen 2010; Papp 2009), some have argued that failure to produce transferable benefits is related in part to problems with task design (Jaeggi 2010). As noted above, CT traditionally involves the repeated practice of a set of structured tasks designed to target particular cognitive processes and abilities. Some study authors have proposed that CT should be divided into subtypes of cognitive exercise and strategy training (Gates 2011), the latter of which involves instruction and practice in the use of specific cognitive strategies designed to further enhance performance, or minimise the impact of impaired cognition (e.g. method of loci, visual imagery) (Hampstead 2016). CT is different from the type of skill training often exercised by occupational therapists, in that the target is usually an underlying process or ability, rather than a specific skill. Early versions of CT tended to be delivered in an inflexible 'one size fits all' approach; however, in recent years, technological developments are leading to increased tailoring of training focus based on the individual cognitive profile and adaptive difficulty level (Bahar‐Fuchs 2017; Peretz 2011). CT may be offered through individual sessions (Davis 2001; de Vreese 1998a; de Vreese 1998b; Farina 2002; Koltai 2001; Loewenstein 2004), it may be provided in group sessions (Cahn‐Weiner 2003; Ermini Fuenfsch 1995; Kesslak 1997; Koltai 2001; Moore 2001), or it may be facilitated by family members with therapist support (Neely 2009; Quayhagen 1995a; Quayhagen 2000). Initially delivered mainly in paper‐and‐pencil format, computerised cognitive training (CCT) programmes have largely replaced more traditional methods over the past two decades (Davis 2001; de Vreese 1998; Quayhagen 1995; Quayhagen 2000). In some cases, the tasks or activities that form the focus of practice/training are analogues of actual daily activities, such as doing online shopping or setting up a dinner table (Farina 2002; Loewenstein 2004; Neely 2009; Zanetti 1994; Zanetti 1997; Zanetti 2001), and in these cases the distinction between CT and functional skills training becomes more difficult. Skills‐oriented interventions in which the target task is well structured and is broken into relatively well‐defined underlying cognitive performance elements, and where the outcomes of interest are cognitive processes rather than merely performance of the intervention task itself (e.g. Neely 2009), appear to fit the conceptual framework of CT. Conversely, when the focus of the intervention is a specific skill and there is no expectation to improve an underlying cognitive ability/process, and where cognitive underpinnings are unclear or are only vaguely addressed, the intervention might be best classified as ‘functional skills training’. In accordance with the suggestion that CT may enhance effects of pharmacological therapy (Newhouse 1997), some studies have evaluated the efficacy of CT in combination with the use of cholinesterase inhibitors (Cahn‐Weiner 2003; de Vreese 1998a; de Vreese 1998b; Loewenstein 2004), or given with other medications (Heiss 1993; Yesavage 1981).

Table 1. Selected characteristics of cognitive training, rehabilitation, and stimulation

Cognitive training

Cognitive rehabilitation

Cognitive stimulation

Target

Impairment

Participation restriction

Participation restriction

Context

Structured tasks and environments

The person’s natural environment

Usually a clinic/residential care or daycare setting

Focus of intervention

Specific cognitive abilities and processes; psychoeducation and strategy training sometimes included

Groups of cognitive abilities and processes required to perform individually relevant everyday tasks; behaviour, environment, and everyday activity. Psychoeducation and strategy training sometimes included

Orientation, global cognitive status

Format

Individualised or group

Individualised

Typically group

Proposed mechanism of action

Mainly restorative; mechanisms related to neuroplasticity

Combination of restorative and compensatory approaches; reduction of 'excess disability'

Improved orientation; general activation

Goals

Improved or maintained ability in specific cognitive domains

Performance and functioning in relation to collaboratively set behavioural or functional goals

Improved overall orientation and engagement in pleasant abilities

How the intervention might work

Cognitive training (CT) aims to improve or maintain specific cognitive processes or global cognitive ability; when used as an intervention approach in clinical populations, it is expected that improvements in cognition will generalise to improvement in functional outcomes. Much has been written about the lack of unifying theories in the field of NPIs, including in relation to interventions aimed at changing behaviour (Michie 2008), in relation to cognition and function (Wilson 2002), and in relation to rehabilitation in general (Hart 2014). Indeed, no single theory exists that comprehensively explains such issues as why or how CT should lead to improved cognitive and functional outcomes, whether and why some cognitive domains are more likely to respond to training than others, whether training should target single or multiple cognitive domains, or whether training should focus on improving impaired functions or building on preserved ones. To various extents, CT interventions in healthy and in clinical populations draw instead on a range of theories and discoveries grounded in cognitive neuroscience (e.g. Jaeggi 2008; Sohlberg 1987), or in clinical practice and rehabilitation of patients with neurological injuries and diseases (Ponsford 2012; Stuss 1999); CT continues to be shaped in response to relevant technological developments including those reported in the gaming industry (Anguera 2015). Unfortunately, many CT interventions have been and continue to be developed without clear reference to any relevant theoretical work.

A central assumption held by many advocates of CT is that training in an underlying cognitive ability or process will lead to generalised improvements that go beyond the training context (Lampit 2014). In cognitively healthy younger and older adults, and to a lesser extent in individuals with mild cognitive impairment (MCI), there is little doubt that CT leads to improvement in trained or 'criterion' tasks. However, in both healthy and clinical populations, the evidence concerning learning transfer remains mixed, and the issue is hotly debated, with much debate concerning identification of barriers and enablers of transfer of gains to untrained tasks that reflect the cognitive domain targeted by the training (near transfer) and other untrained cognitive domains, as well as non‐cognitive outcomes (far transfer) (Jaeggi 2010). In a recent comprehensive review and critique of the commercial CT industry, Simons and colleagues pointed out that discussion concerning transfer of learning can be traced back to very early theoretical accounts (Simons 2016), such as the so‐called formal discipline theory and the theory of transfer by identical elements proposed by Edward Thorndike in the early 20th century. It is beyond the scope of this review to cover these theories in detail, but a critical discussion of these accounts in relation to the CT literature and industry is included in the review by Simons and colleagues (Simons 2016). Contemporary empirical findings suggest that factors that appear to be implicated in CT‐related gain‐transfer include degree of similarity or overlap among elements of trained and transfer tasks, extent of actual gain on trained tasks, baseline cognitive abilities, and age (Zinke 2014).

In addition to theories of learning and transfer, knowledge and expertise related to brain‐behaviour relationships ‐ as well as to mechanisms of injury, disease, and recovery ‐ are critical in informing the development of COTs, including CT, in the context of work with persons with acquired disorders of the central nervous system (including traumatic brain injury, stroke, and neurodegenerative conditions). Historically, such interventions have reflected two broad conceptual frameworks for recovery of function after brain illness or injury: a restorative approach, and a contextualised or compensatory approach (Ylvisaker 2002). Techniques usually associated with cognitive rehabilitation, such as optimising residual cognitive abilities in impaired domains and making the most of unimpaired cognitive abilities, lend themselves more to compensatory approaches (Clare 2001b). In contrast, techniques usually associated with CT, such as the repeated exercise of standardised cognitive tests of increasing difficulty and the targeting of specific cognitive domains, tend to reflect restorative principles and “thrive on the lure of neuroplasticity” (Rabipour & Raz 2012). Indeed, a range of neuroplasticity‐related observations in animal and human studies, including changes at the molecular, synaptic, structural, and functional levels associated with enriched environments and a structured training programme, are routinely cited as the proposed mechanisms of action in CT (Valenzuela 2012). In recent years, growing evidence has shown that CT is associated with changes in patterns of neural activation in key brain regions among healthy older adults (Belleville 2014), as well as in people with MCI (Belleville 2011; Hampstead 2011). Such increased brain activation may be the result of processes of synaptic growth and repair triggered by repeated practice on standardised tests.

Why it is important to do this review

The Alzheimer's disease drug development pipeline is slow, and trials of disease‐modifying treatments have generally failed to produce improvement in any clinically meaningful outcomes, although they have succeeded in disrupting targeted pathophysiological processes (Cummings 2014; Cummings 2016; Salomone 2012), leading some to question the relevance of the dominant amyloid cascade hypothesis when it comes to the development of an effective treatment for dementia as a clinical syndrome (D'Alton 2011). NPIs aimed at developing ways of living better with dementia, in part by targeting relevant clinical outcomes and caregiver burden, are assuming an increasingly central role in the management of dementia and are recognised as an important adjunct, and even alternative, to available pharmacological treatments. A recent Lancet Commission on Dementia Prevention, Intervention, and Care argued that some NPIs can already play an important role in managing some of the cognitive, behavioural, and neuropsychiatric symptoms of dementia, and pointed to positive findings for cognitive stimulation therapy and preliminary supportive evidence on cognitive rehabilitation (Livingston 2017).

In healthy older adults (Edwards 2017; Lampit 2014), and in persons with MCI (Chandler 2016; Hill 2017), systematic review findings on effects of CT on cognitive and several non‐cognitive outcomes have been generally encouraging, and factors associated with increased intervention efficacy in CT are becoming better understood. Indeed, recently published clinical practice guidelines for MCI have classified CT as supported by Level C evidence, meaning that clinicians may recommend this form of intervention (Petersen 2018).

In contrast, most systematic reviews of CT for persons with dementia have to date produced largely negative findings (e.g. Bahar‐Fuchs 2013; Hill 2017; but see Sitzer 2006). Our previous Cochrane Review on CT for persons with dementia included 11 randomised controlled trials but provided no evidence to support CT in relation to any of the examined outcomes. We noted, however, that the certainty of these findings may be reduced by the relatively small number of highly heterogenous studies, which often were of low methodological quality. Against the background of a heavily divided scientific community and an ever growing industry of commercial CT products that have at times made highly misleading claims, it is vital that clinicians, policy‐makers, and the general public are presented with an up‐to‐date, rigorous, and unbiased review of the current literature on CT for persons with mild to moderate dementia.

Objectives

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  • To assess effects of CT on cognitive and non‐cognitive outcomes for people with mild to moderate dementia and their caregivers.

  • To compare effects of CT with those of other non‐pharmacological interventions, including cognitive stimulation or rehabilitation, for people with mild to moderate dementia and their caregivers.

  • To identify and explore factors related to intervention and trial design that may be associated with the efficacy of CT for people with mild to moderate dementia and their caregivers.

Methods

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Criteria for considering studies for this review

Types of studies

In keeping with the previous version of this review, and to ensure the inclusion of unbiased estimates of treatment effects only (Reeves 2011), we considered only randomised controlled trials (RCTs) for inclusion. Wherever possible, we did not exclude studies published in a language other than English, and we made every effort to obtain an English translation from the study authors. In cases where we could not obtain a translation from study authors, we engaged in reasonable efforts to obtain a reliable translation, and we excluded a study only if these efforts were unsuccessful.

Types of participants

We included trials in which all participants had received a medical diagnosis of dementia, of any subtype, as long as the underlying aetiology was assumed to be non‐reversible. It was expected that the diagnosis of dementia was generally made on the basis of established clinical or research diagnostic criteria, including criteria specified by the following.

  • The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM‐V; APA 2013) or earlier versions (APA 1995).

  • The International Classification of Diseases, Tenth Revision (ICD‐10) (WHO 1992).

  • The National Institute of Neurological and Communicative Disorders and Stroke ‐ Alzheimer's Disease and Related Disorders Association (NINCDS‐ADRDA) (McKhann 1984).

  • The National Institutes of Health ‐ Alzheimer's Association (NIH‐AA) (McKhann 2011).

  • The Association Internationale pour la Recherché et l'Enseignement en Neurosciences (NINDS‐AIREN) (Roman 1993).

  • Vascular Impairment of Cognition Classification Consensus Study (McKeith 1996; McKeith 2006; McKeith 2017).

  • The International Behavioural Variant FTD Criteria Consortium (FTDC) (Skrobot 2017).

On average, participants in included studies were classified as having a mild to moderate level of severity. Dementia severity was usually determined in primary trials on the basis of group mean scores, ranges of scores, or individual scores on a standardised scale, such as scores over 12 on the Mini Mental State Examination (MMSE; Folstein 1975), or scores of 0.5 to 2 on the Clinical Dementia Rating scale (CDR 2; Hughes 1982).

  • Studies in which it was clear that only a small proportion of participants (i.e. < 15%) fell within the more severe range or the questionable dementia range were considered acceptable if this information was clearly indicated in the study.

  • Qualifying participants generally resided at home, or in a residential care facility. We excluded studies in which recruited participants could be long‐term residents of psychiatric hospitals, where pre‐existing psychiatric conditions are likely to be present.

  • We set no specific age restrictions, although it was expected that, with the exception of participants with younger‐onset dementia (YOD), most participants would be 65 years of age or older.

  • No restrictions were placed on current pharmacological treatment. When available, information about participants' use of cholinesterase inhibitors was noted.

  • Primary studies that included a mixture of participants, only some of whom meet our inclusion criteria (e.g. dementia, MCI), were eligible for inclusion as long as outcomes were reported separately for the group of interest, or as long as we could obtain that information from trial authors.

Types of interventions

Experimental interventions

Interventions meeting our definition of CT were eligible for inclusion. As the terms used to refer to CT vary considerably, interventions may be referred to as 'brain' or 'mental' training, and they may be described as 'retraining', 'exercise', 'stimulation', 'rehabilitation', 'therapy', 'remediation', 'support', etc.; our operational definition of eligible interventions included the following criteria.

  • Participants were trained on tasks designed to target one or more cognitive processes either directly or indirectly. Training generally took the form of repeated practice. Trials in which the primary goal was to compare performances of participants who learned how to perform a task under different learning conditions (e.g. errorless vs errorful) in a single session (single trial training) were not eligible for inclusion.

  • Tasks were completed in pen‐and‐paper format or through computerised exercises, or were structured analogues of everyday tasks in which the cognitive underpinnings are explicit, and the intervention targeted a cognitive ability or process rather than a specific skill. The nature of the intervention (i.e. computerised or pen‐and‐paper or analogues of daily activities) was noted.

  • Interventions were delivered on commercially available platforms, or were designed specifically for the purposes of the study.

  • Interventions could target single or multiple cognitive domains.

  • Level of difficulty was expected to vary; however, this did not form part of the inclusion criteria.

  • We excluded from this review interventions in which CT was combined with another distinct experimental intervention (e.g. physical activity, brain stimulation), but this did not apply to standard treatments, as participants were generally expected to remain on their standard (usually pharmacological) treatment.

  • Modified/alternative CT: it was acknowledged that CT and other cognition‐oriented treatment approaches (i.e. cognitive stimulation or rehabilitation) may share some features, some of which could not be distinguished in a straightforward manner. Hence, we will include trials of complex cognition‐oriented treatments that also include elements of cognitive stimulation (e.g. orientation), rehabilitation (e.g. goal setting), or psychoeducation (e.g. using cognitive strategies), if it was determined by consensus that CT was clearly the predominant component. When relevant and indicated by statistical heterogeneity, we considered these interventions separately in subgroup analyses.

Comparator interventions

  • Wait‐list. In studies of this type, the experimental intervention was offered to the control group after the study had ended.

  • No treatment/standard treatment. Unless otherwise specified, whenever groups were described as 'no treatment' in individual studies, we assumed that this referred to usual/standard treatment, and not to withholding of treatment. 'Usual or standard treatment' referred to what would normally be provided in the study locality to participants with mild dementia, and might include provision of medication, clinic consultations, and contact with a community mental health team or daycare, or support from voluntary organisations, but not a specific CT intervention.

  • Active control. This referred to conditions in which participants engaged in some form of activity, typically for an equivalent number of sessions or visits, and received similar levels of contact with the researchers, but during which no structured intervention was offered.

  • Alternative treatments. These were distinct, alternative treatments that might (e.g. cognitive stimulation) or might not have been cognition‐focused (e.g. physical activity).

All interventions

  • We did not include interventions conducted in individual or group format, with or without involvement of family caregivers.

  • We did not impose restrictions regarding intervention dose‐related parameters, including overall duration of the intervention or number of treatment sessions. However, as described above, we excluded single‐session treatments.

Types of outcome measures

We considered outcomes within the following broad categories as relevant for this review.

  • Clinical disease progression.

  • Cognitive outcomes.

  • Psychosocial outcomes for the person with dementia.

  • Psychosocial outcomes for the primary caregiver.

  • Surrogate/mechanism/biomarker outcomes.

  • Economic outcomes.

Although it is acknowledged that surrogate and economic outcomes are important, we determined them to be beyond the scope of the current review; therefore we selected the main primary and secondary outcomes from the top four categories, as further outlined below.

Primary outcomes
Outcomes for the person with dementia

  • Global cognitive status at end of treatment (i.e. immediately post intervention). We measured this by determining change in scores on a composite measure of global cognition derived from all cognitive measures included in each trial, with additional analyses focusing on global cognition, as reflected on screening measures of global cognition (e.g. MMSE)

  • Clinical disease severity in the medium term. We measured this by determining change in scores on measures of clinical disease progression (e.g. Clinical Dementia Rating Scale (CDR), Dementia Rating Scale (DRS)) in a follow‐up assessment conducted between 3 and 12 months after treatment cessation

Secondary outcomes
Outcomes for the person with dementia

  • Global cognitive status in the medium term. We measured this by determining change in scores on a composite measure of global cognition at the relevant follow‐up assessment, with additional analyses focusing on global cognition as reflected on screening measures of global cognition (e.g. MMSE)

  • Clinical disease severity at end of treatment. We measured this by determining change in scores on measures of clinical disease progression (e.g. CDR, DRS) in the immediate post‐treatment assessment

  • Domain‐specific cognitive status at end of treatment. We measured this by determining change in scores on neuropsychological measures of speed of processing, immediate memory, delayed memory, attention and working memory, language (naming), verbal letter fluency, verbal category fluency, and executive function

  • Domain‐specific cognitive status in the medium term (3 and 12 months after treatment cessation). We measured this by determining change in scores on neuropsychological measures of speed of processing, immediate memory, delayed memory, attention and working memory, language (naming), verbal letter fluency, verbal category fluency, and executive function

  • Meta‐cognition (subjective beliefs regarding cognition ‐ self‐reported) at end of treatment and in the medium term

  • Meta‐cognition (subjective beliefs regarding cognition ‐ informant‐reported) at end of treatment and in the medium term

  • Mood (as reflected in change in self‐ or informant‐reported measures of depression, anxiety, etc.) at end of treatment and in the medium term

  • Capacity for activities of daily living at end of treatment and in the medium term

  • Behavioural and psychological symptoms of dementia (BPSD) at end of treatment and in the medium term

  • General health or quality of life at end of treatment and in the medium term

  • Participant burden as reflected in rates of retention of trial participants at end of treatment

Outcomes for the primary caregiver at end of treatment

  • Mood and well‐being (as reflected in change in self‐reported measures of depression, anxiety, etc.) at end of treatment and in the medium term

  • Burden of care at end of treatment and in the medium term

  • Quality of life at end of treatment and in the medium term

Outcome measures

Where possible, we used data from published and validated tests, questionnaires, or techniques for evaluation of a given outcome. In cases in which an outcome was evaluated by an unpublished or non‐established measure, we made every effort to source information about statistical properties of the test or scale in question, before determining whether or not to accept the measure. We classified cognitive measures to specific cognitive domains according to established authoritative texts (Spreen 1998), wherever possible, and by consensus between study authors as required.

Outcome evaluation

We included trials if they included, at minimum, a baseline evaluation and one post‐treatment evaluation.

Search methods for identification of studies

Electronic searches

We searched ALOIS (www.medicine.ox.ac.uk/alois), the Specialised Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG), on 5 July 2018.

ALOIS, which is maintained by the Information Specialists for CDCIG, contains studies that fall within the areas of dementia prevention, dementia treatment and management, and cognitive enhancement in healthy elderly populations. These studies are identified by:

  • searching several major healthcare databases: MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and PsycINFO;

  • searching several trial registers: ClinicalTrials.gov and the International Clinical Trials Register Platform (ICTRP) of the World Health Organization (WHO), which includes International Standard Randomized Controlled Trials Number (ISRCTN); the Chinese Clinical Trials Register; the German Clinical Trials Register; the Iranian Registry of Clinical Trials; and the Netherlands National Trials Register, plus others;

  • searching the Central Register of Controlled Trials, in the Cochrane Library (CENTRAL); and

  • searching grey literature sources: Institute for Scientific Information (ISI) Web of Science Core Collection.

To view a list of all sources searched for ALOIS, please visit the ALOIS website (www.medicine.ox.ac.uk/alois).

Details of the search strategies run in healthcare bibliographic databases, used for retrieval of reports of dementia, cognitive improvement, and cognitive enhancement trials, can be viewed on the website of the Cochrane Dementia and Cognitive Improvement Group at http://dementia.cochrane.org/searches.

We ran additional searches in MEDLINE, Embase, PsycINFO, CINAHL, Latin American Caribbean Health Sciences Literature (LILACS), ClinicalTrials.gov, and the WHO Portal/ICTRP, to ensure that searches for this review were as comprehensive and as up‐to‐date as possible. Search strategies used and the number of hits retrieved can be seen in Appendix 1.

Searching other resources

We screened reference lists from included trials, as well as reference lists of recent systematic reviews, and relevant recent guidelines. We contacted experts in the field to request additional randomised trial reports not identified by the search.

Data collection and analysis

Selection of studies

One review author (AM) reviewed titles and abstracts from the complete de‐duplicated list of search results, and we split the records for an independent screening by two additional review authors (ABF, AG), to identify all potentially relevant RCTs of CT for people with dementia and to remove obviously irrelevant studies. Whenever there was doubt regarding the eligibility of a trial, we selected it for full review of the methods. Following the initial screening, we applied the same approach for evaluation of full methods from short‐listed articles. We identified and merged multiple reports from the same study, and we contacted study authors to clarify issues related to the eligibility of a trial for inclusion. We settled discrepancies in the classification of trials through discussion between two review authors and ruling of a senior review author who is a content area expert (LC). The study selection process was unblinded.

Data extraction and management

JS extracted data from study reports onto a standardised, structured data entry form under supervision of the lead review author (ABF), who also independently extracted data for variables requiring some judgement (e.g. intervention integrity/fidelity), and we subsequently entered the data into Review Manager 5 software (Review Manager 5). We sought additional information from study authors as appropriate. Data extracted from each trial included detailed characteristics of trials (e.g. settings, outcomes), design features (e.g. delivery format, blinding), participant characteristics (e.g. diagnoses, age, gender, education, medications), and elements of experimental and control interventions (e.g. intensity, frequency, duration, key intervention features). We also extracted information about additional variables of interest for the investigation of effect moderators, including registration status, sources of funding, conflicts of interest, adherence and retention, type of control, whether intervention integrity/fidelity was addressed, and adverse events. For each outcome of interest, we extracted mean scores and standard deviations on relevant measures from all available evaluations.

Assessment of risk of bias in included studies

Pairs of review authors independently conducted assessment of risk of bias using Cochrane's 'Risk of bias' tool (Higgins 2017). We resolved disagreements by discussion with a third review author who is a subject matter expert (LC). Consistent with Cochrane's 'Risk of bias' tool, we assessed bias in the following domains: sequence generation, allocation concealment, blinding of participants and investigators, incomplete outcome data, and selective reporting of outcomes. We rated studies as 'low risk', 'high risk', or 'unclear risk' in each of these domains.

Measures of treatment effect

We generally calculated effect estimates in primary trials along with their 95% confidence intervals (CIs) using change‐from‐baseline scores. Calculations of the standard deviation of change scores were based on the assumption that the correlation between measurements at baseline and those at subsequent time points is r = 0.8, in keeping with other relevant reviews (e.g. Lampit 2014). However, for consistency with previous versions of this review, we also conducted sensitivity analyses of the primary outcome with a conservative r = 0 assumption, which overestimates the standard deviation of the change. We treated outcome measures as measured on a continuous scale. In some cases, we derived outcomes from ordinal rating scales; provided these contained a reasonably large number of categories (more than 10), we treated data as continuous variables arising from a normal distribution. For dichotomous outcomes (e.g. participant retention), we expressed effects as risk ratios (RRs) along with 95% CIs.

Unit of analysis issues

We expected four types of unit of analysis issues: cross‐over trial designs, multiple‐armed trials (more than one treatment/control condition), repeated assessments, and availability of multiple measures of the same outcome in primary trials. Our approach to the management of these issues was as follows.

  • Cross‐over trials: we used only data from the first treatment period (before cross‐over).

  • Multiple conditions:

    • experimental conditions: in trials that include at least three conditions, assuming that at least one condition satisfies our definition of a comparison condition (see above), we combined data from all conditions that we judged to fit our definition of CT into a single group using a relevant formula (Higgins 2017). We excluded from this review trials that include two relevant experimental conditions but no eligible control condition; and

    • control conditions: we combined data from two control conditions of the same broad type (i.e. no treatment). In the event that a trial included different types of control comparisons that are not alternative treatments (e.g. it included both no treatment and active control groups), we used in the analysis data from both these control conditions by splitting the sample size of the experimental condition into two separate groups, according to the procedure described in Chapter 7 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2017).

  • Repeated post‐intervention assessments: we conducted separate comparisons to assess primary and secondary outcomes at end of treatment (i.e. immediately post intervention), and in the short to medium term (up to 12 months post intervention). Within this follow‐up period, we used in the analysis data from the last available assessment. We did not use data from follow‐up assessments conducted more than 12 months following the end of treatment assessment.

  • Multiple measures of the same outcome: in primary trials in which multiple measures of the same outcome were used, the following principles guided the selection of measures for data extraction:

    • general principles: we used a composite outcome measure if one was derived by the study authors. If no composite was available, we generally used data from a test that matched the most commonly used measure in other studies that contributed data to the particular outcome. Established/published measures of the outcome were preferred over measures developed for the specific study. If more than one established measure of an outcome was used, and no measure was identified that was used by most trials contributing to the specific outcome, we created a simple composite score from standardised scores on the different measures and used it in the analysis;

    • cognitive outcomes: for each trial, we computed a global composite cognitive score by calculating a standardised change‐from‐baseline score for each measure (change score divided by the standard deviation of the change score), and deriving a simple mean and standard deviation of the z‐scores associated with all cognitive measures from a trial. In addition, for evaluation of domain‐specific cognitive scores, we used the following principles:

      • Psychomotor information processing speed: we preferred visuospatial measures where available.

      • Attention, immediate and delayed memory: we preferred auditory‐verbal measures for evaluation of attention and immediate and delayed memory. We preferred tasks that involve the learning of information over several trials (i.e. word lists) over tasks in which the information is presented only once (e.g. story or figure recall). We preferred measures of free recall over measures of cued/recognition where available.

      • Executive functions: we preferred tasks that reflect planning, organisation, decision‐making, regulation of performance, and set‐shifting aspects of executive functions over tasks that are more strongly associated with volition or purposive action aspects of executive functions (Lezak 2004). In the event that several measures of executive function were used in a study, we computed a composite executive function score by taking the mean of standardised scores for each of these measures.

    • Meta‐cognitive outcomes: we generally preferred self‐reported measures of contentment/satisfaction with one's cognitive ability over informant‐reported measures;

    • Mood outcomes: we generally preferred measures of depression over measures of anxiety or apathy, and self‐reported measures over informant‐reported measures; and

    • Activities of daily living (ADLs): we preferred measures of instrumental ADLs over measures of basic ADLs, and informant‐reported measures over self‐reported measures. This is based on the finding that self‐ and informant‐reported daily functions show significant discrepancy in people with dementia, and that informant reports of daily function are more closely associated with actual memory performance (Farias 2005).

Dealing with missing data

We extracted the number of participants who commenced and completed the intervention in each condition, and this contributed to our assessment of risk of bias due to incomplete outcome data. Wherever possible, we contacted trial authors in an effort to obtain relevant unreported data. In general, we assumed that data were missing at random, and that analyses in individual studies were generally performed on a per‐protocol (PP) rather than on an intention‐to‐treat (ITT) basis. When a trial report included relevant data from both ITT and PP samples, we generally used the PP data for consistency with most of the trials. We evaluated the impact of missing data on pooled effect estimates by performing sensitivity analyses (see below).

Assessment of heterogeneity

In addition to a visual inspection of the forest plots, we assessed statistical heterogeneity using a standard Chi² statistic and the associated l² statistic. Consistent with recommendations (Deeks 2017), we deemed heterogeneity to be present when the Chi² statistic is significant at the P = 0.1 level, or when l² suggests that more than 40% of the variability in the effect estimate is due to heterogeneity. Where substantial heterogeneity was detected, we explored the sources of heterogeneity by conducting subgroup analyses (see below).

Assessment of reporting biases

For primary outcomes, we first evaluated the presence of reporting bias through visual examination of funnel plots for small‐study effects. We examined the significance of any apparent asymmetry by using Egger's test (Egger 1997), and by providing follow‐up with the 'trim and fill' test (Duval 2000), if asymmetry of the plot was confirmed.

Data synthesis

We performed data synthesis using Review Manager 5 software. In relation to each of the main outcomes of interest, we undertook the following separate comparisons.

  • CT versus control (no/standard treatment/wait‐list or active control) at end of treatment (i.e. immediately post intervention).

  • CT versus control (no/standard treatment/wait‐list or active control) in the medium term (3 to 12 months following end of treatment).

  • CT versus alternative treatment at end of treatment (i.e. immediately post intervention).

  • CT versus alternative treatment in the medium term (3 to 12 months following end of treatment).

Within each of the planned comparisons, we pooled data in relation to each outcome of interest when data from at least two trials were available.

We performed inverse‐variance, random‐effects meta‐analyses for all outcomes. We used mean differences (MDs) with 95% CIs whenever studies used the same outcome measure, whereas we used standardised mean differences (SMDs), which show the absolute mean difference divided by the pooled standard deviation, when the same outcome was assessed by different measures.

Subgroup analysis and investigation of heterogeneity

In relation to each outcome, we carried out subgroup analyses to evaluate the potential impact of categorical treatment modifiers. We carried out subgroup analyses only when statistical heterogeneity was suggested by the relevant statistics (I² ≥ 40%) (Deeks 2017), and when at least three studies were available for each subgroup. We examined the following categorical effect modifiers.

  • Type of intervention 1: 'straight' CT versus 'augmented' CT ‐ in which CT was combined with elements of cognitive rehabilitation or cognitive stimulation (or both).

  • Type of intervention 2: multi‐domain CT versus single‐domain CT (e.g. working memory).

  • Intervention dose: more intense (i.e. more than three formal sessions per week) versus less intense interventions (i.e. up to three formal sessions per week).

  • Intervention duration: longer interventions (i.e. more than three months) versus shorter interventions (i.e. three months or less).

  • Follow‐up period: we compared studies with follow‐up in the short term (up to three months after treatment cessation) versus trials that included longer‐term follow‐up (up to 12 months after treatment cessation).

  • Risk of bias: studies with high risk of bias in at least two critical domains versus other studies with lower risk of bias. For the purposes of these analyses, critical domains were sequence generation, blinding of outcome assessment, incomplete data, and selective reporting. Although we acknowledge that allocation concealment is increasingly regarded as a critical domain, this remains a relatively infrequent practice in these types of studies.

  • Funding source: trials funded by commercial entities versus those based on competitive funding.

  • Registration: registration status of the trial (prospective/retrospective vs not registered/not reported).

Sensitivity analysis

To determine whether findings for the primary outcomes were affected by assumptions made regarding strength of the correlation between scores before and after the interventions, we repeated analyses of the primary outcomes after applying the zero correlation assumption, which overestimates the standard deviation of change scores. We repeated evaluation of primary outcomes by performing a further sensitivity analysis using post‐intervention scores only, thus avoiding the need to estimate the standard deviation of change scores.

GRADE and 'Summary of findings' tables

We expressed our overall confidence in the evidence for each outcome using GRADE, and we presented this in 'Summary of findings' tables and in the review text. We described the quality of evidence as 'high', 'moderate', 'low', or 'very low', using the GRADE framework, which we applied to all primary and secondary outcomes in each comparison. In relation to each outcome, we considered certainly in the estimates in relation to risk of bias, indirectness, inconsistency, imprecision, and publication bias for studies contributing data to estimation of the outcome. Two review authors (ABF and JS) worked together to grade the evidence. We considered estimates based on data from a single study against the same parameters, with the exception of inconsistency and publication bias dimensions. In relation to risk of bias, we generally downgraded by 1 point, reflecting serious concern, when sensitivity analysis in which we removed studies classified as at overall 'high risk' led to a difference in the estimate of effect of between 0.2 standard deviation (SD) and 0.3 SD. We downgraded by 2 points, reflecting very serious concern, when sensitivity analysis led to a difference in the estimate of effect that was greater than 0.3 SD. We generally downgraded by 1 point for serious concerns regarding inconsistency when moderate heterogeneity was observed (40% < l² < 75%) and when subgroup analyses (when relevant; see below) did not seem to explain heterogeneity in the estimates. We generally downgraded by 2 points when high heterogeneity (l² > 75%) was observed and when subgroup analyses (when relevant) did not seem to explain the heterogeneity. Concerning imprecision, following the rule of thumb in the GRADE Handbook, we downgraded by 1 point when the sample size on which the estimate was based was smaller than 400 participants, or in the event that the confidence interval of the estimate included both a potentially important effect and a clinically unimportant effect (defined as an effect smaller than 0.2 in either direction for continuous outcomes). We downgraded by 2 points when the estimate was based on fewer than 400 participants (for continuous outcomes), and when the CI of the estimate included both a potentially important effect and no effect, or in the event that the CI included all relevant possibilities (positive effect, no effect, and effect in the opposite direction), irrespective of the sample size. Regarding publication bias, we indicated that it was 'strongly suspected' in cases where on visual inspection, asymmetry in the funnel plot for a relevant outcome was reasonably evident. We did not conduct formal tests of asymmetry, and we inspected funnel plots only when at least 10 studies contributed to the outcome. Hence, we could not evaluate this for many outcomes, including all outcomes in the comparison between cognitive training and use of an alternative treatment. Finally, we generally regarded the correspondence between findings in relation to various outcomes and the review question as specified in the PICO to be adequate, so we decided not to downgrade the evidence on the basis of indirectness.

We generated 'Summary of findings' tables using GRADEpro GDT software (GRADEpro GDT), and we imported these into the review. summary of findings Table for the main comparison, summary of findings Table 2, summary of findings Table 3, and summary of findings Table 4 include the following primary and secondary outcomes.

  • Global cognition at end of intervention.

  • Clinical disease severity at latest follow‐up, up to 12 months following treatment cessation.

  • Delayed memory ability at end of intervention.

  • Capacity to perform activities of daily living.

  • Mood and well‐being of participant.

  • Mood and well‐being of informant/caregiver.

  • Treatment burden (retention rates).

Results

Description of studies

Results of the search

The flow of studies through the search and screening process can be seen in Figure 1 (review flow chart). After de‐duplication, 1166 records underwent full title and abstract review, on the basis of which we deemed 157 titles to be potentially relevant; we then reviewed the full text of these studies (when available) to confirm eligibility. The full‐text review revealed that 33 studies met our inclusion criteria and 32 studies contributed data for at least one meta‐analysis. Of these, 10 studies were included in a previous Cochrane Review on CT and rehabilitation for people with mild to moderate dementia (Bahar‐Fuchs 2013).
 

Figure 1
Study flow diagram.

Study flow diagram.

Included studies

Pertinent details of the included studies, extracted from the published manuscript and, where noted, provided by study authors, are presented in the Characteristics of included studies table. Further details concerning the characteristics of participants in included studies are presented in Table 1, and details concerning dose and duration of the interventions are shown in Table 2. The 33 studies selected for inclusion in the current review were published between 1988 and 2018. With the exception of Davis 2001 and Barban 2016, which did not use a cross‐over design, all trials were parallel‐group RCTs. Amieva 2016, Barban 2016, Beck 1988, Jelcic 2014, Kallio 2018, Kao 2016, Lee 2013, and Tsantali 2017 were described as multi‐site trials; all others were assumed to be single‐site trials. Only three of the included trials made reference to registration in a public trial registry; Brueggen 2017 and Kallio 2018 were prospectively registered, whereas Kao 2016 was retrospectively registered. We assumed that all other trials were unregistered. The included trials were conducted in 12 countries, with six conducted in the USA (Beck 1988; Cahn‐Weiner 2003; Davis 2001; Koltai 2001; Quayhagen 1995; Quayhagen 2000), two in Germany (Brueggen 2017; Heiss 1993), 12 in Italy (Bergamaschi 2013; Cavallo 2016; de Vreese 1998; Galante 2007; Giovagnoli 2017; Giuli 2016; Jelcic 2012; Jelcic 2014; Mapelli 2013; Serino 2017; Trebbastoni 2018; Venturelli 2016 ), one in Sweden (Neely 2009), one in Japan (Kawashima 2005), three in France (Amieva 2016; Boller 2011; Goudour 2011), two in Spain (Fernández‐Calvo 2011; Quintana Hernandez 2014), two in China (Kao 2016; Lee 2013), one in Korea (Kim 2015), one in Greece (Tsantali 2017), and one in Finland (Kallio 2018). Barban 2016 was a multi‐country trial with recruitment in Italy, Greece, Norway, and Spain. It is worth noting that approximately one‐third of all included studies (13) were conducted in Italy, 10 of these in the past six years. We further note that no eligible trials were found from the UK, Canada, or Australia, and that no eligible studies were found that were conducted in the USA since 2003 (these studies were all included in a previous review ‐ Bahar‐Fuchs 2013). Samples in the included studies ranged from 12 participants in Galante 2007 to 653 participants in Amieva 2016, and 13 of the included studies had samples of more than 50 participants. Of the 33 included studies, 30 were published in English, two in Spanish, and one in French. A member of the review team (JS) translated essential information from Spanish and French studies to English.

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Table 1. Summary characteristics of participants in cognitive training and control groups

Study
 

Condition

Sample size (at baseline)

Age, mean (SD),

range

Gender balance (m:f)

Education

Medications (number or proportion on dementia‐related medication)

Baseline MMSE

score

Retention rates

Adverse reactions

Beck 1988

Cognitive training

10

74 (range 68 to 75)

5:5

Attended college = 2

None

Not reported

100%

"many subjects complained of tiring"
 

Control

10

76 (range 70 to 93)

3:7

Attended college = 1

None

Not reported

100%

Not specified

Heiss 1993

Cognitive training

Not reported (18

completed the study)

65.9 (6.28)

9:9

Not reported

None

20.55 (4.42)

Not reported

Not specified

Control (social support)

Not reported (17

completed the study)

66.63 (10.17)

10:7

Not reported

None

20.23 (4.10)

Not reported

Not specified

Control (CT+pyritinol)

17

67.18 (8.51)

Not reported

88.88

Not reported

21.64 (4.55)

Not reported

Not specified

Control (CT+phosphatidylserine)

18

66.74 (6.93)

Not reported

125

Not reported

20.88 (4.73)

Not reported

Not specified

Quayhagen 1995

Cognitive training

25

Not reported

Not reported

Not reported

Not reported

109.8 (12.0) DRS

Not reported

Not specified

Passive control

25

Not reported

Not reported

Not reported

Not reported

109.2 (11.7) DRS

Not reported

Not specified

Active control

28

Not reported

not reported

Not reported

Not reported

110 (12.2) DRS

Not reported

Not specified

de Vreese 1998

Cognitive training

12

NA

NA

NA

NA

NA

NA

NA

Cognitive training+AChE‐I

12

Not reported

Not reported

Not reported

All

17.33 (3.39)

100%

Not specified

Control (placebo drug)

12

Not reported

Not reported

Not reported

All

17.44 (4.67)

100%

Not specified

Control (AChE‐I)

12

Not reported

Not reported

Not reported

All

17 (3.20)

100%

Not specified

Quayhagen 2000

Cognitive training

21

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Passive control

15

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Dyadic counselling control

29

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Seminar groups control

22

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Early‐stage daycare control

16

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Davis 2001

Cognitive training

19

68.67 (3.86)

10:9

15.06 (3.86)

5

21.84 (4.03)

100%

Not specified

Control

18

72.56 (7.62)

6:12

12.97 (2.56)

4

22.78 (4.45)

100%

Not specified

Koltai 2001

Cognitive training (group and individual) ‐ shared data

16

72.9 (6.7)

Not reported

15.0 (4.0)

Not reported

22.9 (3.6)

87.5% (missed: 2 participants from group CT)

Not specified

Control

8

73.9 (7.2)

Not reported

15.0 (4.0)

Not reported

26.6 (2.5)

100%

Not specified

Cahn‐Weiner 2003

Cognitive training

19

77. 8 (6.9)

9:8

12.7 (2.1)

All participants: donepezil

24.3 (2.2)

89.4% (missed: 3 participants)

Not specified

Control

20

76.0 (7.7)

5:12

13.1 (3.5)

All participants: donepezil

25.1 (1.7)

85% (missed: 3 participants)

Not specified

Galante 2007

Cognitive training

7

Not reported

Not reported

Not reported

All

22.9 (3.1)

100%

Not specified

Control

5

Not reported

Not reported

Not reported

All

23.1 (1.8)

80% (missed: 1 participant)

Not specified

Neely 2009

Cognitive training

10

74.8 (6.7)

6:4

Not reported

Not reported

22.9 (4.15)

100%

Not specified

Control

10

77.0 (6.6)

6:4

Not reported

Not reported

18.6 (5.7)

90% (missed: 1 participant)

Not specified

Kawashima 2005

Cognitive training

16

85.1 (5.4) (range 76 to 96)

Not reported

Not reported

Not reported

19.9 (7.0)

100%

Not specified

Control

16

86.3 (4.9) (range 78 to 96)

Not reported

Not reported

Not reported

19.6 (5.4)

Not reported

Not specified

Boller 2011

Cognitive training (recollection)

12

81.58

4:8

10.92 (2.94)

Not reported

24 (3.05)

Not reported

Not specified

Cognitive training (recognition)

12

82.67

4:8

12.08 (2.07)

Not reported

24.83 (2.12)

Not reported

Not specified

Control

12

79.33 (3.85)

5:7

11.08 (3.85)

Not reported

25.83 (1.40)

Not reported

Not specified

Fernández‐Calvo 2011

Cognitive training (BBA)

15

75.80 (4.27)

9:6

7.46 (1.84)

All participants on IaCHe

19.33 (2.48)

Not reported

Not specified

Cognitive training (IPP)

15

75.60 (4.55)

8:7

8.40 (2.77)

All participants on IaCHe

20 (2.92)

Not reported

Not specified

Control

15

75.86 (4.15)

8:7

7.26 (3.34)

All participants on IaCHe

20.44 (1.90)

Not reported

Not specified

Goudour 2011

Cognitive training

5

68.8 (10.0)

2:3

9.0 (1.2)

Not reported

20.2 (2.8)

Not reported

Not specified

Control

5

70.0 (5.9)

2:3

9.6 (1.9)

Not reported

20.6 (4.1)

Not reported

Not specified

Jelcic 2012

Cognitive training

20

82.9 (3.6)

2:18

6.7 (2.9)

Not reported

24.4 (2.8)

100%

Not specified

Control

20

81.8 (5.5)

5:15

8.25 (3.6)

Not reported

25 (2.6)

100%

Not specified

Bergamaschi 2013

Cognitive training

16

78.19 (5.50)

Not reported

7.25 (3.24)

All participants: donepezil 5 or 10 mg/d

20.25 (2.95)

Not reported

Not specified

Control

16

77.72 (5.06)

Not reported

5.61 (2.30)

All participants: donepezil 5 or 10 mg/d

21.94 (2.01)

Not reported

Not specified

Lee 2013

Cognitive training (CELP)

6

Not reported

1:6

Nil: 42.8%
< 2 years: 14.3%
3 to 6 years: 28.6%
Secondary: 14.3%
University: 0%

Not reported

15.3 (2.7)

Not reported

Not specified

Cognitive training (TELP)

6

Not reported

3:3

Nil: 16.7%
< 2 years: 16.7%
3 to 6 years: 33.2%
Secondary: 16.7%
University: 16.7%

Not reported

17.6 (4.7)

Not reported

Not specified

Control

7

Reported

2:4

Nil: 33.3%
< 2 years: 16.7%
3 to 6 years: 16.7%
Secondary: 33.3%
University: 0%

Not reported

17 (3.5)

Not reported

Not specified

Mapelli 2013

Cognitive training

10

82.6 (4.85)

Not reported

4.6 (1.5)

Not reported

20.1 (4.2)

100%

Not specified

Control (occupational therapy)

10

84.5 (5.06)

Not reported

4.3 (1.82)

Not reported

19.7 (3.8)

100%

Not specified

Control (no treatment)

10

84.7 (4.42)

Not reported

4 (1.15)

Not reported

18.8 (2.68)

100%

Not specified

Jelcic 2014

Cognitve training (LSS‐tele)

7

86 (5.1)

2:5

6 (3.5)

Not reported

23.7 (2.8)

Not reported

Not specified

Cognitive training (LSS‐direct)

10

82.7 (6)

3:7

6.7 (3.3)

Not reported

24.9 (2.5)

Not reported

Not specified

Control

10

82.3 (5.9)

1:9

8.7 (3.7)

Not reported

24.8 (2.7)

Not reported

Not specified

Quintana Hernandez 2014

Cognitive training

32

Not reported

Not reported

Not reported

100% donepezil

Not reported

84.3%

Not specified

Control muscular relaxation

34

Not reported

Not reported

Not reported

100% donepezil

Not reported

97%

Not specified

Control mindfulness

36

Not reported

Not reported

Not reported

100% donepezil

Not reported

97.2%

Not specified

Control

25

Not reported

Not reported

Not reported

100% donepezil

Not reported

100%

Not specified

Kim 2015

Cognitive training

22

70.4 (7.9)

8:14

8.7 (3.8)

Not reported

23.1 (2.1)

100%

Not specified

Control

21

71.4 (8.2)

7:14

8.5 (3.1)

Not reported

22.8 (1.8)

100%

Not specified

Amieva 2016

Cognitive training

170

78.5 (7.2)

69:99 (data from 168 participants)

No diploma: 10%
Primary school diploma: 34.7%
Secondary school: 29.4%
Baccalaureate and more: 23.5%

89.4% IaCHe, memantine

21.5 (3.2)

72.94% (missed: 46 participants)

Not specified

Usual care

154

78.7 (6.5)

63:90 (data from 154 participants)

No diploma: 15.6%
Primary school diploma: 33.1%
Secondary school: 29.2%
Baccalaureate and more: 20.8%

86.4% IaCHe, memantine

21.6 (3.3)

70.78% (missed: 45 participants)

Not specified

Reminiscence therapy

172

78.8 (6.9)

61:108 (data from 169 participants)

No diploma: 16.3%
Primary school diploma: 33,7%
Secondary school: 30.8%
Baccalaureate and more: 16,9%

90.1% IaCHe, memantine

21.1 (3.1)

68.60% (missed: 54 participants)

Not specified

Individualised cognitive rehabilitation

157

78.9 (6.2)

64:92 (data from 172 participants)

No diploma: 17.2%
Primary school diploma: 35.7%
Secondary school: 26.8%
Baccalaureate and more: 19.1%

86.6% IaCHe, memantine

21.6 (3.0)

77.07% (missed: 36 participants)

Not specified

Cavallo 2016

Cognitive training

40

76.5 (2.88)

13:27

8.53 (3)

36/40

22.65 (1.74)

100%

Not specified

Control

40

76,33 (3,83)

16:24

8.12 (2.79)

38/40

23.05 (2.44)

100%

Not specified

Kao 2016

Cognitive training (spaced retrieval)

48

83.10 (5.0)

33:13

Illiterate: 14 (30, 4)
Primary school: 11 (23, 9)
High school: 14 (30, 4)
College: 7 (15, 2)

Not reported

12.33 (5.41)

95.83% (missed: 2 participants)

Not specified

Cognitive training (spaced retrieval+Montessori activities)

52

82.69 (6.81)

37:12

Illiterate: 9 (18, 4)
Primary school: 13 (26, 5)
High school: 17 (34, 6)
College: 10 (20, 4)

Not reported

12.08 (4.05)

94.23% (missed: 3 participants)

Not specified

Control

48

81.82 (5.89)

Male 29 (64, 4)
Female 16 (35, 6)

Illiterate: 13 (28, 9)
Primary school: 15 (33, 3)
High school: 12 (26, 7)
College: 5 (11, 1)

Not reported

11.84 (5.49)

93.75% (missed: 3 participants)

Not specified

Barban 2016

Cognitive training

42

76.5 (5.7)

13:29

8.8 (3.6)

Not reported

23.4 (1.9)

94.79% (from the 3 groups, not only PWD)

Not specified

Control

39

76.9 (5.7)

11:28

9.2 (3.7)

Not reported

23.4 (1.7)

89.14% (from the 3 groups, not only PWD)

Not specified

Giuli 2016

Cognitive training

51

76.5 (4.3)

40:60

5.9 (4.1)

Not reported

20.2 (3.7)

94.11% (missed: 3 participants)

Not specified

Control

50

78.7 (5.9)

28:72

4.5 (2.3)

Not reported

20.3 (3.5)

94% retention (missed: 3 participants)

Not specified

Venturelli 2016

Cognitive training

20

86 (9)

5:15

Not reported

No anti‐dementia drugs reported

14.0 (1.6)

100%

Not specified

Aerobic exercise

20

84 (7)

4:16

Not reported

No anti‐dementia drugs reported

13.7 (2.3)

100%

Not specified

Aerobic exercise+Cognitive training

20

85 (8)

6:14

Not reported

No anti‐dementia drugs reported

13.8 (1.5)

100%

Not specified

Control

20

84 (10)

17:13

Not reported

No anti‐dementia drugs reported

14.2 (1.5)

100%

Not specified

Tsantali 2017

Cognitive training

17

73.4 (5.7)

Not reported

9.9 (4.2)

All were on inhibitors of cholinesterase, used for at least 2 years

23.2 (1.6)

100%

Not specified

Alternative treatment (cognitive stimulation)

21

74.2 (5.6)

Not reported

9.5 (4.1)

All were on inhibitors of cholinesterase, used for at least 2 years

23.1 (1.4)

100%

Not specified

Control

17

73.3 (4.9)

Not reported

9.8 (4.0)

All were on inhibitors of cholinesterase, used for at least 2 years

22.5 (0.9)

100%

Not specified

Brueggen 2017

Cognitive training

8

(53 to 80)

4:4

(10 to 17)

5 participants on anti‐dementia medication

24 (3.55)

100%

Not specified

Control

10

(59 to 83)

5:3

(11 to 17)

All 8 participants were on anti‐dementia medication

21.75 (3.24)

80% (missed: 2 participants)

Not specified

Serino 2017

VR group ‐ AD

10

86.60
(6.13)

1:9

9.80 (3.97)

Not reported

22.05 (1.62)

100%

Not specified

VR group ‐ normal ageing

8

86.62 (6.19)

4:4

9.12 (5.05)

Not reported

27.73 (2.02)

100%

Not specified

Control

10

88.70 (3.59)

2:8

7.00 (5.00)

Not reported

20.79 (1.80)

100%

Not specified

Giovagnoli 2017

Cognitive training

13

71.69 (7.88)

3:10

6.92 (2.46)

Not reported

23.62 (1.94)

100% (4 dropped out before treatment)

No adverse effects

Alternative treatment (music therapy)

13

73.92 (7.74)

7:6

10.46 (5.3)

Not reported

22.85 (6.28)

100% (4 dropped out before treatment)

No adverse effects

Alternative treatment (neuroeducation)

13

75.31 (5.56)

8:5

7.31 (4.01)

Not reported

21.15 (3.48)

100% (3 dropped out before treatment)

No adverse effects

Trebbastoni 2018

Cognitive training

54

74.26 (6.97)

28:26

8.64 (4.21)

78% AChEIs
27% donezepil 5 mg
24% donezepil 10 mg
20% rivastigmine 9.5 mg
7% rivastigmine 4.6 mg
2% memantine 20 mg

22.20 (2.37)

88.80% (missed: 6 participants)

2 falls (group is not reported) and 2 deaths (1 from each group). Study authors stated that these events were not related to any of the experimental procedures performed

Control

86

76.01 (6.46)

34:52

8.40 (4.12)

88% AChEIs,
40% donepeziil 5 mg
20% rivastigmine 9.5 mg
18% donepezil 10 mg
12% rivastigmine 4.6 mg
2% memantine 20 mg

22.89 (2.72)

100%

2 falls (group is not reported) and 2 deaths (1 from each group). Study authors stated that these events were not related to any of the experimental procedures performed

Kallio 2018

Cognitive training
 

76

82.6 (5.5)
 

34.2% male

32 < 8 years
 

60 (78.9%) taking AD medications; 33 (43.4%) taking anticholinergics
 

21.0 (4.3)
 

68 of 76
 

Not specified
 

 

Control

71

83.6 (5.4)

21.1% male

36 < 8 years
 

62 (87.4%) taking AD medications; 37 (52.1%) taking anticholinergics
 

19.9 (3.9)
 

49 of 71
 

Not specified
 

Date in the table, in some cases, are reported only for those participants who completed the interventions.

AChEI: anti‐cholinesterase inhibitor.

AD: Alzheimer's disease.

BBA: Big Brain Academy.

CELP: computerised errorless learning‐based memory training programme.

CT: cognitive traininng.

IPP: Integrated Psychostimulation Program.

LSS: lexical‐semantic simulation.

TELP: therapist‐led errorless programme.

VR: virtual reality.

Open in table viewer
Table 2. Summary of duration of interventions and timing of assessments

Study

Duration (weeks)

Session frequency (per week)

Total number of sessions

Session duration (minutes)

Total direct intervention (minutes)

Total direct intervention (hours)

Session format

Adherence rates

Fidelity measures

Beck 1988

6 (cognitive training)

3

18

Approx. 35

Approx. 630

Approx. 10.5

Individual, with a research assistant

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA

Heiss 1993

24 (cognitive training)

2

48

60

2880

48

Individual

Not reported

Not reported

24 (social support)

1

24

60

1440

24

Individual

Not reported

Not reported

24 (cognitive training+pyritinol)

2

48

60

2880

48

Individual

Not reported

Not reported

24 (cognitive training+phosphatidylserine)

2

48

60

2880

48

Individual

Not reported

Not reported

Quayhagen 1995

12 (cognitive training)

6

72

60

4320

72

Individual

Not reported

Caregiver and care recipient were trained together in programme implementation techniques. Return demonstrations by caregivers were required to validate training

NA (passive control)

NA

NA

NA

NA

NA

NA

NA

NA

12 (active control)

Not reported

Not reported

Not reported

Not reported

Not reported

Not reported

Not reported

Caregiver and care recipient were trained together in programme implementation techniques. Return demonstrations by caregivers were required to validate training

de Vreese 1998

NA (cognitive training)

NA

NA

NA

NA

NA

NA

NA

NA

12 (cognitive training+ChE‐I, after 12 weeks on drug)

2

24

45

1080

18

Individual

Not reported

Not reported

12 (placebo drug)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

12 (AChE‐I, after 12 weeks on drug)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

Quayhagen 2000

8 (cognitive training)

1

8

90

720

12

Individual, with help from caregiver

Not reported

Ongoing monitoring of personnel performance to ensure uniformity and consistency of administration of assessments or interventions

8 (dyadic counselling)

1

8

90

720

12

Dyad

Not reported

Ongoing monitoring of personnel performance to ensure uniformity and consistency of administration of assessments or interventions

8 (seminar groups)

1

8

90

720

12

Group

Not reported

Ongoing monitoring of personnel performance to ensure uniformity and consistency of administration of assessments or interventions

8 (daycare)

7

8

240

1920

32

Group

Not reported

Ongoing monitoring of personnel performance to ensure uniformity and consistency of administration of assessments or interventions

NA (wait‐list control)

NA

NA

NA

NA

NA

NA

NA

NA

Davis 2001

5 (cognitive training)

1

5

60

300

5

Individual

Not reported

Not reported

5 (control)

1

5

60

300

5

Individual

Not reported

Not reported

Koltai 2001

5 (cognitive training ‐ group)

1

5

60

300

5

Group

Not reported

Not reported

6 (cognitive training ‐ individual)

1

6

Not reported

Not reported

Not reported

Individual

Not reported

Not reported

NA (wait‐list control)

NA

NA

NA

NA

NA

NA

NA

NA

Cahn‐Weiner 2003

6 (cognitive training)

1

6

Not reported

Not reported

Not reported

Group, with a clinical neuropsychologist

1 participant did not complete the first session, and 2 participants did not complete the fourth session

"All sessions were identical for all participants, with the memory group instructor relying on a trainer's manual with scripts for how to present the information"

6 (control)

1

6

45

270

4.5

Group, with a clinical neuropsychologist

4 participants missed 1 session, and 1 participant missed 2 sessions

Not reported

Galante 2007

4 (cognitive training)

3

12

60

720

12

Individual, with a neuropsychologist

Not reported

Not reported

4 (control)

3

12

60

720

12

Individual, with a neuropsychologist

Not reported

Not reported

Neely 2009

8 (cognitive training ‐ collaborative intervention)

1

8

30 to 40

Approx. 280

Approx. 4.5

Dyads, with a research assistant

Not reported

Not reported

8 (cognitive training ‐ individual intervention)

1

8

30 to 40

Approx. 280

Approx. 4.5

Individual, with a research assistant

Not reported

Not reported

NA (control group)

NA

NA

NA

NA

NA

NA

NA

NA

Kawashima 2005

24 (cognitive training)

2 to 6

48 to 144

Approx. 20

960 to 2880

16 to 48

Individual, with the possibility to ask staff members for advice

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

Boller 2011

2 (cognitive training ‐ recollection)

12

24

60

1440

24

Not reported

Not reported

Not reported

2 (cognitive training ‐ recognition)

12

24

60

1440

24

Not reported

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA

Fernández‐Calvo 2011

12 (cognitive training ‐ BBA)

3

36

60

2160

36

Individual, with an OT and a psychologist

Not reported

Not reported

12 (cognitive training ‐ IPP)

3

36

60

2160

36

Individual, with an OT and a psychologist

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA

Goudour 2011

12 (cognitive training)

1

12

50

600

10

Individual, with a neuropsychologist.

Not reported

Not reported

12 (control)

1

12

50

600

10

Individual, with a clinical psychologist.

Not reported

Not reported

Jelcic 2012

12 (cognitive training)

2

24

60

1440

24

Group, provided by a neuropsychologist

Not reported

Not reported

12 (control)

2

24

60

1440

24

Group, provided by a neuropsychologist

Not reported

Not reported

Bergamaschi 2013

20 (cognitive training)

5

100

120

12000

200

Group, supervised by a neuropsychologist

Not reported

Not reported

20 (control)

Presumed to be 5

Not reported

Not reported

Not reported

Not reported

Group

Not reported

Not reported

Lee 2013

6 (cognitive training ‐ CELP)

2

12

30

360

6

Individual, with a therapist

Not reported

Not reported

6 (cognitive training ‐ TELP)

2

12

30

360

6

Individual, with a therapist

Not reported

Not reported

6 (active control)

2

12

30

360

6

Not reported

Not reported

Not reported

Mapelli 2013

8 (cognitive training)

5

40

60

2400

40

With a therapist

Not reported

Not reported

8 (control ‐ occupational therapy)

5

40

60

2400

40

Not reported

Not reported

Not reported

NA (control ‐ usual care)

NA

NA

NA

NA

NA

NA

NA

NA

Jelcic 2014

12 (cognitive training ‐ LSS‐tele)

2

24

60

1440

24

Small groups, provided by a therapist

Not reported

Not reported

12 (cognitive training ‐ LSS‐direct)

2

24

60

1440

24

Small groups, provided by a therapist

Not reported

Not reported

12 (control)

2

24

60

1440

24

Small groups, provided by a therapist

Not reported

Not reported

Quintana Hernandez 2014

104 (cognitive training)

3 (IPP)

288

90

25920

432

Group, with a clinical psychologist

Not reported

Not reported

104 (muscular relaxation)

3

288

90

25920

432

Group, with a clinical psychologist

Not reported

Not reported

104 (mindfulness)

3

288

90

25920

432

Group, with a clinical psychologist

Not reported

Not reported

NA (passive control)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

Kim 2015

8 (cognitive training)

1

8

60

480

8

Individual and in a group

Not reported

Not reported

8 (control)

1

8

60

480

8

Not reported

Not reported

Not reported

Amieva 2016

96 (cognitive training)

1 (during the first 3 months); 1 every 6 weeks (for the next 21 months)

15

90

1350

22.5

Groups

Not reported

Manual detailing the guidelines of each intervention was provided. Standardised procedures to guarantee homogeneity. Professional visits to therapists to ensure that interventions were applied in accordance with protocol

NA (control ‐ usual care)

NA

NA

NA

NA

NA

NA

NA

NA

96 (reminiscence therapy)

1 (during the first 3 months); 1 every 6 weeks (for the next 21 months)

15

90

1350

22.5

Groups

Not reported

Manual detailing the guidelines of each intervention was provided. Standardised procedures to guarantee homogeneity. Professional visits to therapists to ensure that interventions were applied in accordance with protocol

96 (cognitive rehabilitation)

1 (during the first 3 months); 1 every 6 weeks (for the next 21 months)

15

90

1350

22.5

Individual

Not reported

Manual detailing the guidelines of each intervention was provided. Standardised procedures to guarantee homogeneity. Professional visits to therapists to ensure that interventions were applied in accordance with protocol

Cavallo 2016

12 (cognitive training)

3

36

30

1080

18

Individual, with a neuropsychologist

Not reported

Not reported

12 (control)

3

36

30

1080

18

Individual, with a neuropsychologist

Not reported

Not reported

Kao 2016

6 (cognitive training ‐ spaced retrieval)

5

30

40

1200

20

With a trainer

Not reported

Not reported

6 (cognitive training ‐ spaced retrieval+Montessori activities)

5

30

40

1200

20

With a trainer

Not reported

Not reported

na (control)

NA

NA

NA

NA

NA

NA

NA

NA

Barban 2016

12 (cognitive training)

2

24

60

1440

24

Small groups, provided by a cognitive therapist

Not reported

Not reported

12 (control)

NA

NA

NA

NA

NA

NA

NA

NA

Giuli 2016

10 (cognitive training)

1

10

45

450

7.5

Individually, with homewrok exercises with support of a caregiver

Not reported

Not reported

10 (control)

1

10

45

450

7.5

Not reported

Not reported

Not reported

Venturelli 2016

12 (cognitive training)

5

60

60

3600

60

Performed in collaboration with patients’ caregivers

85±12% in the CT group

Not reported

12 (aerobic exercise)

5

60

60

3600

60

Performed in collaboration with patients’ caregivers

78±8% in the AE group

Not reported

12 (aerobic exercise+cognitive training)

5

60

60

3600

60

Performed in collaboration with patients’ caregivers

75±14% in the AE+CT group

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA

Tsantali 2017

16 (cognitive training)

3

48

90

4320

72

Individual with licensed psychologist

Not reported

Not reported

16 (cognitive stimulation)

3

48

90

4320

72

Individual with licensed psychologist

Not reported

Not reported

16 (control)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

Brueggen 2017

12 (cognitive training)

5

60

Approx. 15

Approx. 900

Approx. 15

Individual homework, with 1 meeting per month

100%

Not reported

12 (cognitive rehabilitation)

2

24

60

1440

24

Small group guided by a psychologist and an occupational therapist

100% (including only the 8 participants who completed the study and were, therefore, analysed)

Intervention was based on the CORDIAL programme, via a manual‐guided approach

Giovagnoli 2017

12 (cognitive training)

2

24

45

1080

18

Small groups of 3 participants, guided by a neuropsychologist

Not reported

CT was co‐ordinated by a neuropsychologist using defined materials and procedures

12 (music therapy)

2

24

45

1080

18

Small groups of 3 participants, guided by a music therapist

Not reported

Active music therapy was provided by a music therapist. Sessions were videotaped and evaluated via a structured assessment

12 (neuroeducation)

2

24

45

1080

18

Small groups of 3 participants, co‐ordinated by a neurologist

Not reported

Not reported

Serino 2017

3‐4 (VR group ‐ AD)

3

10

20

200

3.3

Individual with a neuropsychologist

Not reported

Not reported

3‐4 (VR group ‐ normal ageing)

3

10

20

200

3.3

Individual with a neuropsychologist

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

Underwent traditional cognitive rehabilitative activities with the neuropsychological staff

NA

NA

Trebbastoni 2018

24 (cognitive training)

2

48

75

3600

60

Group

11% (6 participants) attended less than 80% of sessions of the first period of the study (from T0 to T1).
In the second period, 72.9% attended more than 95% of sessions, 10,4% attended 90% to 95%, 4.2% attended 85% to 89%, and 12.5% attended 80% to 84%

Study authors reported high adherence to a strict protocol

NA

NA

NA

NA

NA

NA

NA

NA

NA

Kallio 2018

12 (cognitive training)

2

24

45

1080

18

Group/individual when required
 

Mean attendance at 22 (92%) sessions
 

CT was administered by trained psychology students under the supervision of an experienced neuropsychologist

 

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA
 

AChEI: anti‐cholinesterase inhibitor.

AD: Alzheimer's disease.

BBA: Big Brain Academy.

CELP: computerised errorless learning‐based memory training programme.

ChEI: cholinesterase inhibitor.

CT: cognitive traininng.

IPP: Integrated Psychostimulation Program.

LSS: lexical‐semantic simulation.

NA: not applicable.

TELP: therapist‐led errorless programme.

VR: virtual reality.

General characteristics of participants 

Participants in all trials had a diagnosis of mild to moderate dementia according to the published paper. Diagnosis was based exclusively on NINCDS‐ADRDA criteria in 12 of the included trials, whereas six studies used either NINCDS‐ADRDA or DSM‐IV criteria, and one study used either NINCDS‐ADRDA or Milan Overall Dementia Scale (MODS) criteria. In four studies, diagnoses were supported by scores on the Mini Mental State Examination (MMSE) test alone, and one study used MMSE in combination with the Global Deterioration Scale (GDS). Two studies used DSM‐IV alone, three used the Clinical Dementia Rating Scale (CDR) alone, and one used the Chinese version of the Dementia Rating Scale (DRS) alone. Two studies used the DRS in combination with the GDS, and one study used physician judgement as the basis for diagnosis. In almost all trials, the presumed aetiology was AD, but other aetiologies were suspected in some studies: probable mixed dementia (Beck 1988); cardiovascular dementia or Parkinson's disease (Quayhagen 2000); vascular dementia (Neely 2009); and Parkinson's disease, vascular dementia, Lewy body dementia, or unknown dementia (Kallio 2018). With the exception of a small number of studies in which participants were recruited from hospital or nursing home facilities (Beck 1988; Cavallo 2016; Kawashima 2005; Mapelli 2013; Venturelli 2016), participants generally resided in the community. Severity of dementia among participants residing in a nursing home environment may have been somewhat greater, with MMSE scores ranging between 15 and 20 in Beck 1988, between 7 and 30 in Kawashima 2005, between 14 and 24 in Mapelli 2013, and between 10 and 15 in Venturelli 2016.

In two studies, the mean age of participants was greater than 65, but less than 70 years (Heiss 1993; Goudour 2011). In 19 of the included studies, the mean age of participants was between 70 and 80 years (Cavallo 2016; Quayhagen 1995; Tsantali 2017). In ten of the included trials, the mean age of participants was greater than 80 years (Boller 2011; Kawashima 2005; Kallio 2018). Two studies did not report the mean age of participants although, in both of them, they were 50 years and above (Brueggen 2017; Lee 2013)

General characteristics of experimental interventions

All studies included at least one condition that met our criteria for CT. In six studies, two conditions met our criteria for CT (Boller 2011; Fernández‐Calvo 2011; Jelcic 2014; Koltai 2001; Lee 2013; Neely 2009), and for these studies, data from the two conditions were combined as specified in the protocol to form a single experimental condition. Of a total of 39 CT interventions, 26 were classified as multi‐domain interventions and 13 as single‐domain interventions (Boller 2011; Cahn‐Weiner 2003; Davis 2001; Goudour 2011; Jelcic 2012; Jelcic 2014; Kao 2016; Lee 2013; Neely 2009). We classified most experimental interventions as 'straight CT', but we classified 13 experimental interventions as 'augmented CT' due to the inclusion of additional elements, usually associated with reality orientation, cognitive stimulation, or cognitive rehabilitation, as was the case with de Vreese 1998 or Davis 2001, Mapelli 2013 or Kim 2015, for example. We classified 23 of the 39 experimental interventions as primarily individual training (although in some cases, participants could receive some assistance from their caregivers) and 11 as group training. Two experimental conditions involved a combination of group and individual training (Kallio 2018; Kim 2015), and one experimental treatment involved dyads (Neely 2009). The remaining studies provided insufficient detail to show whether participants in the experimental conditions were trained individually or in a group (Boller 2011; Kao 2016).

General characteristics of comparison conditions

In seven studies, two conditions met our criteria for a comparison condition (Brueggen 2017; de Vreese 1998; Giovagnoli 2017; Kao 2016; Mapelli 2013; Venturelli 2016; Tsantali 2017). In a further two studies (Amieva 2016; Quintana Hernandez 2014), three conditions met our criteria for comparison conditions, and in one study (Quayhagen 2000), four conditions could be classified as comparison conditions. We classified 17 of the comparison conditions as passive controls (involving a wait‐list condition, a no‐contact condition, placebo medication, or usual care (i.e. continuing with usual activities of the nursing home or hospital, or receiving conventional medical care)) and 14 as active controls (including social support groups, activities similar to those in the experimental condition but with a passive approach, unstructured conversation or discussion, educational information, semi‐structured interviews, clinical support, unstructured or non‐specific cognitive activity, and other non‐specific activities). We considered that 15 interventions met our criteria for an alternative treatment. These included a new medication (de Vreese 1998); dyadic counselling, dual supportive seminar groups, and early‐stage daycare programmes (Quayhagen 2000); occupational therapy (Mapelli 2013); mindfulness and muscular relaxation (Quintana Hernandez 2014); reminiscence therapy and cognitive rehabilitation (Amieva 2016; Brueggen 2017); and spaced retrieval combined with Montessori activities (Kao 2016), aerobic exercise (Venturelli 2016), cognitive stimulation (Tsantali 2017), and music therapy and neuroeducation (Giovagnoli 2017).

Intervention dose and duration

The duration of interventions ranged from two weeks in Boller 2011 to approximately 104 weeks in Quintana Hernandez 2014. In seven of the 33 studies, the intervention lasted three months or longer (Amieva 2016; Bergamaschi 2013; Heiss 1993; Kawashima 2005; Quintana Hernandez 2014; Trebbastoni 2018; Tsantali 2017). In nine studies, researchers delivered the intervention in more than three sessions per week (Bergamaschi 2013; Boller 2011; Brueggen 2017; Kao 2016; Kawashima 2005; Mapelli 2013; Quayhagen 1995; Quintana Hernandez 2014; Venturelli 2016).

Excluded studies

We have summarised the characteristics of excluded studies in the Characteristics of excluded studies table.

Risk of bias in included studies

We have summarised risk of bias for individual studies, along with a justification for our ratings, in the Characteristics of included studies tables. We have summarised risk of bias for specific domains across studies in Figure 2 and Figure 3.

Figure 2
Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Figure 3
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Allocation

Although all studies are described as randomised trials, many studies provided insufficient detail regarding the randomisation procedure to determine whether the sequence was indeed random; accordingly we rated these as having unclear risk of bias. We rated two studies as having high risk of selection bias, generating the sequence in a manner that was unlikely to be truly random (Galante 2007; Jelcic 2014). We rated studies in which a remote, computerised randomisation method was carried out as low risk in relation to allocation concealment, as this is intrinsic to the method (e.g. Amieva 2016; Kallio 2018). However, we assumed that allocation was not concealed in studies that generated the sequence in a manner that did not guarantee allocation concealment or that provided insufficient detail concerning the randomisation procedure, and did not state explicitly that allocation was concealed (e.g. Beck 1988; Kawashima 2005).

Blinding

In most studies, post‐intervention assessments were performed by research staff, who were unaware of the condition to which participants were assigned, although a small number of studies provided insufficient detail to ensure that this was done (Kawashima 2005; Quayhagen 1995; Quintana Hernandez 2014). However, in approximately 25% of trials (Barban 2016; Beck 1988; Boller 2011; Brueggen 2017; Giuli 2016; Heiss 1993; Koltai 2001; Neely 2009; Serino 2017), unmasked personnel completed outcome assessments, leading to increased risk of detection bias. In relation to performance bias, because blinding of those delivering the intervention typically is not possible in studies of CT, we focused our assessment of risk on the extent to which participants were blinded to whether they were assigned to an experimental or control intervention. This is not possible in studies that included only a passive (e.g. treatment as usual) control condition; we therefore rated these studies as having high risk of performance bias. We rated studies that used an active control or an alternative treatment as having unclear risk of performance bias if no mention was made of an attempt to mask whether the allocated condition was an experimental or control intervention. We rated approximately 90% of studies as having high or unclear risk of performance bias.

Incomplete outcome data

In approximately 50% of the included studies, we found no evidence of attrition bias; however, we judged about half of the remaining studies to have unclear risk (e.g. Giovagnoli 2017; Quayhagen 2000), and we judged half to be at high risk of bias due to attrition (e.g. de Vreese 1998; Tsantali 2017).

Selective reporting

In most cases, studies seem to have reported all outcomes, or study authors provided them in the required format upon request. We sought information from trial registries to determine whether all pre‐specified outcomes were reported, but we found no published protocols for any of the included studies.

Effects of interventions

See: Summary of findings for the main comparison Cognitive training compared to control immediately post intervention for people with mild to moderate dementia; Summary of findings 2 Cognitive training compared to control in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia; Summary of findings 3 Cognitive training compared to alternative treatment immediately post intervention for people with mild to moderate dementia; Summary of findings 4 Cognitive training compared to alternative treatment in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

We summarised main outcomes when CT was compared with control interventions at end of treatment in summary of findings Table for the main comparison.

We summarised main outcomes when CT was compared with control interventions in the medium term in summary of findings Table 2.

We summarised main outcomes when CT was compared with alternative treatments at end of treatment in summary of findings Table 3.

We summarised main outcomes when CT was compared with alternative treatments in the medium term in summary of findings Table 4.

Participant outcomes

Global cognition (composite outcome measure) at end of treatment (primary outcome) and in the medium term (secondary outcome)
Comparison with control

We found a small to moderate effect favouring CT relative to a control condition on the primary outcome, namely, global cognition measured with a composite cognitive score at end of training (standardised mean difference (SMD) 0.42, 95% confidence interval (CI) 0.23 to 0.61; 27 trials; 1389 participants; Analysis 1.1; Figure 4). Our certainty in this finding is moderate due to heterogeneity in effect estimates, which was not explained by planned subgroup analyses. We did not detect clear evidence of publication bias when examining the funnel plot in Figure 5. We performed a more conservative sensitivity analysis in which we assumed no correlation between observations before and after the intervention and still found moderate‐quality evidence of a small beneficial effect of CT relative to a control on global cognition at end of treatment (SMD 0.24, 95% CI 0.12 to 0.36; Analysis 1.2).

Figure 4
Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.1 Change in a global measure of cognition (composite).

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.1 Change in a global measure of cognition (composite).

Figure 5
Funnel plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.1 Change in a global measure of cognition (composite).

Funnel plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.1 Change in a global measure of cognition (composite).

We were uncertain whether CT had an effect relative to a control condition on a composite measure of global cognition in the medium term (i.e. between 3 and 12 months post treatment) due to the very low quality of evidence, both in our main analysis (SMD 0.65, 95% CI 0.11 to 1.2, 8 trials; 387 participants; Analysis 2.1) and in a sensitivity analysis in which we assumed no correlation between observations before and after the intervention (SMD 0.40, 95% CI 0.09 to 0.71; Analysis 2.2). Quality concerns were related to risk of bias, heterogeneity, and imprecision. 

Comparison with an alternative treatment

In comparison with an alternative treatment, we found no clear evidence of an effect of CT on a global measure of cognition at end of treatment, but the quality of evidence for this finding is low due to very serious imprecision (SMD 0.21, 95% CI ‐0.23 to 0.64; 7 trials; 769 participants; Analysis 3.1; Figure 6). In a more conservative sensitivity analysis, assuming zero correlation between observations before and after the intervention, we found there may be little or no effect of CT (SMD ‐0.03, 95% CI ‐0.23 to 0.17; Analysis 3.2) on a composite global cognition score at end of training. The quality of evidence related to this outcome is also low.

Figure 6
Forest plot of comparison: 3 Cognitive training vs alternative treatment immediately post intervention, outcome: 3.1 Change in a global measure of cognition (composite).

Forest plot of comparison: 3 Cognitive training vs alternative treatment immediately post intervention, outcome: 3.1 Change in a global measure of cognition (composite).

In the medium term, we were unable to determine whether CT was associated with any gains in global cognition relative to an alternative treatment because of the very low quality of evidence (SMD 1.31, 95% CI ‐1.03 to 3.65; 2 studies; 73 participants; Analysis 4.1Analysis 4.2).

Global cognition (screening measures) at end of treatment and in the medium term (secondary outcomes)
Comparison with control

Findings were similar when global cognition was assessed using a screening measure, typically the MMSE (although nine studies used another measure as well as the MMSE, including the Alzheimer's Disease Assessment Scale ‐ cognitive subscale (ADAS‐Cog), the Milan Overall Dementia Scale (MODA), the Cambridge Cognitive Assessment (CAMCOG), and the complete neuropsychological battery (ENB‐2), and one study used only the ADAS‐Cog). We found low‐quality evidence suggesting a moderate effect of CT on global cognition at end of training (SMD 0.65, 95% CI 0.26 to 1.05; 20 trials; 1288 participants; Analysis 1.3; Figure 7) and a smaller but still beneficial effect in our more conservative sensitivity analysis (SMD 0.27, 95% CI 0.04 to 0.50; Analysis 1.4).

Figure 7
Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.3 Change in a global measure of cognition.

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.3 Change in a global measure of cognition.

We are unable to determine whether there is any effect on global cognition assessed with screening measures in the medium term due to the very low quality of evidence, including following a sensitivity analysis (6 trials; 387 participants; Analysis 2.3Analysis 2.4). Quality concerns were related to risk of bias, heterogeneity, and imprecision.

Comparison with an alternative treatment

We are uncertain of any effect of CT on a global measure of cognition when compared to an alternative treatment immediately after the intervention due to the very low quality of evidence (SMD 0.16, 95% CI ‐0.28 to 0.60; 7 trials; 724 participants; Analysis 3.3). This was also true in the medium term (SMD 3.20, 95% CI ‐2.89 to 9.29; 2 trials; 73 participants; Analysis 4.3).

Subgroup analyses

To explore the sources of heterogeneity in our main comparison for global cognition, we performed several pre‐specified subgroup analyses, including type of control condition (see Analysis 10.3), type of CT (see Analysis 8.3; Analysis 9.3), dose delivered (frequency and duration; see Analysis 6.3; Analysis 7.3), and risk of bias (see Analysis 5.3). We found no significant differences between subgroups in any of the subgroup analyses in relation to global cognition, although we found non‐significant trends suggesting that trials in which the intervention was delivered at a frequency greater than three times per week were associated with larger effects than trials in which the intervention was delivered up to three times per week (Analysis 6.3), and that traditional CT trials were associated with larger effect sizes than 'augmented' CT trials (Analysis 8.1).

Clinical disease severity at end of treatment (secondary outcome)
Comparison with control

We found a large effect of CT relative to a control condition on the secondary outcome of clinical disease severity at end of treatment (SMD 1.07, 95% CI 0.59 to 1.55; 6 trials; 215 participants; Analysis 1.5). However, owing to concerns regarding heterogeneity and imprecision, our certainty in the accuracy of the estimate is low.

Comparison with an alternative treatment

When compared with an alternative treatment, we found no evidence of an effect of CT on clinical disease severity, and the quality of the evidence was low due to very serious imprecision (SMD 0.15, 95% CI ‐0.33 to 0.63; 3 trials; 131 participants; Analysis 3.5).

Clinical disease severity in the medium term (primary outcome)
Comparison with control

We were unable to determine whether there is an effect of CT relative to a control intervention on the primary outcome of clinical disease severity in the medium term (3 to 12 months post treatment), as the quality of the evidence is very low due to concerns regarding risk of bias and imprecision (SMD 0.55, 95% CI 0.12 to 0.98; 2 trials; 98 participants; Analysis 2.5Figure 8). We performed a sensitivity analysis in which a conservative assumption of no correlation between observations before and after the intervention was applied to the data, and we were again unable to determine whether there was any effect of CT relative to a control condition on clinical disease severity in the medium term due to the very low quality of evidence (SMD 0.28, 95% CI ‐0.14 to 0.71; Analysis 2.6).

Figure 8
Forest plot of comparison: 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), outcome: 2.5 Change in disease progression.

Forest plot of comparison: 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), outcome: 2.5 Change in disease progression.

Comparison with an alternative treatment

None of the included studies measured this outcome in the medium term.

Specific cognitive domains (secondary outcomes)
Comparison with control

Results comparing effects CT versus a control condition at end of treatment on specific cognitive domains (secondary outcomes) are depicted in Analysis 1.6Analysis 1.7Analysis 1.8Analysis 1.9Analysis 1.10Analysis 1.11Analysis 1.12Analysis 1.13 and Figure 9. CT showed a positive effect in immediate and delayed memory, attention and working memory, language (naming), executive functions, and verbal category fluency immediately after the intervention. However, with the exception of findings regarding category fluency (high certainty), our certainty in findings concerning specific cognitive domains was generally very low to low. As can also be seen in Analysis 2.7Analysis 2.8Analysis 2.9Analysis 2.10Analysis 2.11Analysis 2.12Analysis 2.13 and Analysis 2.14, gains in some of the specific cognitive domains (delayed memory, naming, executive functions, and verbal category fluency) were maintained in the medium term. However, again, with the exception of category fluency scores (high certainty), our certainty in these findings ranges from low to very low.

We performed pre‐specified subgroup analyses to explore effects of sources of heterogeneity in the comparison of CT versus control interventions on scores in specific cognitive domains, including high risk of bias studies versus lower risk of bias studies, type of CT (traditional vs augmented), type of domain (multi‐domain vs single domain), and type of control group (passive vs active). Subgroup analyses suggest that the intervention dose moderated effects of CT on verbal letter fluency (Chi² = 3.96, df = 1, P = 0.05), and larger effects were associated with interventions delivered more than three times per week (SMD 1.0, 95% CI 0.09 to 1.92; 3 trials; 84 participants) relative to interventions delivered up to three times per week (SMD 0.05, 95% CI ‐0.13 to 0.24; 9 trials; 460 participants; Analysis 6.9; Figure 10). In addition, subgroup analyses suggest that type of CT moderated effects on verbal category fluency (Chi² = 4.81, df = 1, P = 0.03), and multi‐domain training was associated with larger effects (SMD 0.70, 95% CI 0.38 to 1.02; 6 trials; 371 participants) than single‐domain training (SMD 0.14, 95% CI ‐0.25 to 0.52; 3 trials; 104 participants; Analysis 9.12; Figure 11). We found no other explanations of heterogeneity in other subgroup analyses.

Figure 9
Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.6 Change in delayed memory.

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.6 Change in delayed memory.

Figure 10
Forest plot of comparison: 6 Cognitive training vs control immediately post intervention ‐ intervention dose, outcome: 6.9 Change in verbal letter fluency.

Forest plot of comparison: 6 Cognitive training vs control immediately post intervention ‐ intervention dose, outcome: 6.9 Change in verbal letter fluency.

Figure 11
Forest plot of comparison: 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), outcome: 9.12 Change in verbal category fluency.

Forest plot of comparison: 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), outcome: 9.12 Change in verbal category fluency.

Comparison with an alternative treatment

Results comparing effects of CT versus an alternative treatment at end of treatment on specific cognitive domains are depicted in Analysis 3.6Analysis 3.7Analysis 3.8Analysis 3.9Analysis 3.10Analysis 3.11Analysis 3.12 and Analysis 3.13. Due to the very low quality of evidence, we could not determine whether CT is associated with any benefit for specific cognitive domains compared with an alternative treatment at the end of the intervention. Results for comparison of CT versus an alternative treatment in the medium term are depicted in Analysis 4.6Analysis 4.7Analysis 4.8Analysis 4.9Analysis 4.10Analysis 4.11Analysis 4.12 and Analysis 4.13. As can be seen, with the exception of immediate and delayed memory, other specific cognitive domains were evaluated by a single study; therefore we could not perform meta‐analyses. The quality of evidence in relation to all of these outcomes was low to very low, so we are unable to determine whether, relative to an alternative treatment, CT is associated with any gains in specific cognitive domains in the medium term.

Meta cognition ‐ self‐reported (secondary outcome)
Comparison with control

We found no evidence that CT had an effect on self‐rated cognitive ability immediately post treatment (SMD 0.12, 95% CI ‐0.87 to 1.12; 2 trials; 41 participants; Analysis 1.14; Analysis 2.15). However, the quality of evidence was low, and the findings were very imprecise. Data for this outcome in the medium term were available from only one trial (Lee 2013), in which participants in the experimental condition (which combined data from two experimental conditions ‐ a computerised version and a non‐computerised version of the training) reported fewer difficulties related to prospective memory following treatment relative to control. However, this is a very small trial (n = 19), which we rated to be at high risk of attrition bias due to incomplete outcome data and at high risk of selection bias due to lack of allocation concealment. Given the subjective nature of the outcome, and use of a 'no treatment' control condition, our certainty in this finding is very low. Therefore, we are unable to determine whether CT is associated with any gains in meta cognition in the medium term relative to a control treatment.

Comparison with an alternative treatment

Data concerning this outcome were not available in the comparison of CT versus an alternative treatment in the immediate or medium term.

Meta cognition ‐ informant‐reported (secondary outcome)
Comparison with control

We are unable to determine whether relative to a control condition, CT had an effect on informant‐rated cognitive ability immediately post training due to very low quality of the evidence (SMD ‐0.01, 95% CI ‐1.29 to 1.26; 2 trials; 56 participants; Analysis 1.15). In the medium term, a single study found no evidence of an effect of CT on informant‐rated cognition in the medium term (SMD ‐0.06, 95% CI ‐0.73 to 0.62; Analysis 2.16), but the quality of the evidence was low (Cahn‐Weiner 2003).

Comparison with an alternative treatment

No studies contributed to this outcome when comparing CT versus alternative treatments in the immediate or medium term.

Mood (secondary outcome)
Comparison with control

We are unable to determine whether relative to a control condition, CT had an effect on participants' mood, as reflected on measures of depression, because the quality of the evidence was very low due to concerns related to inconsistency and imprecision (SMD 0.72, 95% CI ‐0.10 to 1.54; 8 trials; 577 participants; Analysis 1.16, Figure 12). We found no evidence of an effect of CT over a control condition in the medium term. The quality of evidence was low due to very serious imprecision; thus, our results were inconclusive (i.e. between 3 and 12 months post treatment; SMD 0.21, 95% CI ‐0.54 to 0.96; 2 trials; 30 participants; Analysis 2.17). We performed pre‐specified subgroup analyses to explore the sources of heterogeneity in participants’ mood when CT was compare with control, including type of control condition and type of CT (traditional vs augmented). The test for subgroup differences could not explain heterogeneity in traditional CT versus augmented CT (P = 0.64), nor in passive control versus active control (P = 0.71) (Analysis 8.15Analysis 10.15).

Figure 12
Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.16 Change in participants' mood.

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.16 Change in participants' mood.

Comparison with an alternative treatment

When compared with an alternative treatment, we found that CT probably had little or no effect on participants’ mood immediately post treatment; we are moderately certain of this finding (SMD ‐0.11, 95% CI ‐0.29 to 0.07; 3 trials; 543 participants; Analysis 3.16). Only one study contributed to this same outcome in the medium term (Giovagnoli 2017); therefore we could not perform a meta‐analysis. Results of this study suggest that benefits in the medium term may favour an alternative treatment (SMD ‐0.66, 95% CI ‐1.35 to 0.02). However, due to very serious concerns related to imprecision, the quality of the evidence was low; therefore, the results are inconclusive.

Capacity for activities of daily living (secondary outcome)
Comparison with control

Relative to a control intervention, we found that CT may have little to no effect on capacity for activities of daily living immediately post treatment (SMD 0.12, 95% CI ‐0.11 to 0.35; 10 trials; 687 participants; Analysis 1.17Figure 13); however the quality of the evidence was low due to concerns related to risk of bias and imprecision. Therefore clear evidence is lacking.

Figure 13
Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.17 Change in capacity for activities of daily living.

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.17 Change in capacity for activities of daily living.

We also found no evidence that CT has an effect on activities of daily living in the medium term (SMD 0.22, 95% CI ‐0.5 to 0.94; 3 trials; 64 participants; Analysis 2.18); the quality of evidence was again low due to very serious concerns regarding imprecision. Therefore clear evidence is lacking.

Comparison with an alternative treatment

We are moderately certain that CT, when compared with an alternative treatment, has little or no effect on participants' capacity for activities of daily living at end of treatment (SMD ‐0.25, 95% CI ‐0.43 to ‐0.07; 3 trials; 525 participants; Analysis 3.17). No studies evaluated this outcome in the medium term.

General health and quality of life (secondary outcome)
Comparison with control

Because the quality of evidence was very low, we are unable to determine whether, relative to a control condition, CT had an effect on general health and quality of life immediately post intervention (SMD ‐0.04, 95% CI ‐0.38 to 0.29; 5 trials; 630 participants; Analysis 1.18). In the medium term, only one study contributed to this outcome; therefore, we could not perform a meta‐analysis (Kallio 2018). This study found no evidence of any CT relative to a control condition (SMD ‐0.02, 95% CI ‐0.39 to 0.35; Analysis 2.19), but the quality of the evidence was low due to very serious imprecision.

Comparison with an alternative treatment

In comparison with an alternative treatment, the quality of the evidence was low. We found that an alternative treatment may be favoured, but these results were imprecise, so there could be little or no effect of CT immediately post intervention (SMD ‐0.49, 95% CI ‐1 to 0.02; 4 trials; 631 participants; Analysis 3.18). Only one study contributed to this outcome in the medium term, finding no evidence of a positive effect of CT relative to alternative treatment (SMD 0.33, 95% CI ‐0.34 to 1; Analysis 4.18), but the quality of evidence was low, so the results are inconclusive (Giovagnoli 2017).

Behavioural and psychological symptoms of dementia (secondary outcome)
Comparison with control

The quality of the evidence was very low due to serious concerns related to heterogeneity and imprecision, so we are unable to determine whether, relative to a control treatment, CT had an effect on behavioural and psychological symptoms of dementia immediately post intervention (SMD 0.44, 95% CI ‐0.34 to 1.22; 6 trials; 493 participants).

In the medium term, only one study contributed to this outcome and found no evidence of an effect of CT on general health and quality of life (SMD ‐1.34, 95% CI ‐2.75 to 0.07; 1 trial; 11 participants; Analysis 2.20) (Galante 2007). However, we have low certainty in this result.

Comparison with an alternative treatment

We found moderate‐quality evidence showing that CT probably has no effect relative to an alternative treatment immediately post intervention (SMD ‐0.11, 95% CI ‐0.27 to 0.06; 3 studies; 672 participants; Analysis 3.19). No trials compared CT versus an alternative treatment on this outcome in the medium term.

Participant burden (retention rates at end of treatment) (secondary outcome)

Meta‐analyses of participant retention rates at end of treatment showed that participants receiving CT were not more likely to discontinue participating in the trial relative to participants receiving a control (odds ratio (OR) 0.73, 95% CI 0.37 to 1.43; 17 trials; 1282 participants; Analysis 1.20Figure 14) or an alternative treatment (OR 0.78, 95% CI 0.24 to 2.57; 4 trials; 639 participants; Analysis 3.20), but our certainty in these findings is very low to low due to imprecision; therefore, our results are inconclusive.

Figure 14
Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.20 Participant burden (retention rates).

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.20 Participant burden (retention rates).

Caregiver outcomes

Comparison with control

Results concerning caregiver outcomes are depicted in Analysis 1.21Analysis 1.22Analysis 1.23Analysis 3.21Analysis 3.22Analysis 3.23 and Figure 15. The quality of evidence in relation to quality of life of the caregiver immediately at the end of treatment was low, and we found no evidence of any effects of CT relative to a control condition (SMD 0.16, 95% CI ‐0.50 to 0.83; 1 trial; 36 participants; Analysis 1.22). We also found moderate‐quality evidence showing that CT was not associated with lower burden of care at end of treatment relative to a control treatment (SMD ‐0.11, 95% CI ‐0.36 to 0.15; 2 trials; 405 participants; Analysis 1.21). One study found a positive effect of CT on caregiver mood at end of treatment relative to control (SMD 0.98, 95% CI 0.27 to 1.68; 1 trial; 36 participants; Analysis 1.23) (Quayhagen 2000). We have moderate certainty in this finding.

Figure 15
Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.23 Change in mood and well‐being (CAREGIVER).

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.23 Change in mood and well‐being (CAREGIVER).

Comparison with an alternative treatment

Based on one study (Quayhagen 2000), we found moderate‐quality evidence of a positive effect of CT on caregiver mood at end of treatment relative to alternative treatment (SMD 1.5, 95% CI 0.96 to 2.04; 1 trial; 88 participants; Analysis 3.23). No available studies evaluated caregiver outcomes in the medium term.
 

Discussion

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Summary of main results

The aim of the current review was to evaluate current evidence regarding effects of cognitive training (CT) interventions on several key outcomes for people with mild to moderate dementia; we found 33 studies that met our inclusion criteria. We carried out separate comparisons of CT versus a control intervention (passive or active) and CT versus an alternative treatment. Key findings of this review are that CT probably has small to moderate positive effects on global cognition, as well as on the specific cognitive domain of verbal semantic fluency immediately after treatment, and these gains may be maintained in the medium term when compared with a passive or active control intervention. Although improvements at the end of treatment were found in several other cognitive domains or processes, the quality of evidence was generally low, so our certainty in these findings is low. Beyond cognition, CT may be associated with slower clinical progression immediately following treatment and in the medium term, but again, we are very uncertain of this finding. We found no evidence of increased participant burden associated with CT (as reflected in discontinuation rates). We carried out several prespecified subgroup analyses to explore potential effect modifiers but found that none were significant.

In contrast, we found no strong evidence of any benefit associated with CT relative to other treatments in relation to our primary outcomes of global cognition at end of treatment and clinical disease severity in the medium term, but our certainty in many of these findings is low. We also found no benefit associated with CT in relation to any of the secondary outcomes included in this review, and in fact, alternative treatments may have been favoured in relation to participants' mood, behavioural and psychological symptoms, or capacity for activities of daily living, but findings were imprecise and our confidence in them is low.

Overall completeness and applicability of evidence

Numbers and sources of studies that met review criteria

The current review included 33 randomised controlled trials (RCTs) with a total of 1924 participants, making it the largest systematic review on this topic to date. Eighteen studies, i.e. more than half of the total included studies, were published since 2013, when a previous Cochrane Review that covered CT studies and included only 10 studies was published (Bahar‐Fuchs 2013). The large number of studies published in recent years was somewhat unexpected, given that in recent years, the focus of many intervention trials has shifted to the pre‐dementia phase of mild cognitive impairment (MCI) and cognitively unimpaired older adults at risk of dementia. In addition, previous reviews, including Cochrane and other reviews (e.g. Hill 2017; Oltra‐Cucarella 2016), generally found little evidence to support CT for people with dementia. Against this context, the increasing number of trials of CT for people with dementia was surprising, but the availability of a relatively large number of studies generally strengthens our confidence in the findings of this current review. The included studies were conducted in over 12 countries, and in the current review, we did not restrict inclusion to studies published in English. It is worth noting, however, that a vast majority of studies, particularly those published in recent years, were conducted in European countries, and 11 of those were conducted in Italy alone. We found no eligible studies that were conducted in English‐speaking countries such as the UK, Canada, or Australia, and all included studies that were conducted in the USA were included in previous reviews preceding 2013. The reasons for this trend are not clear, but the extent to which findings of the current review are applicable to individuals in other countries is not completely clear.

Issues related to definition and scope of interventions

Although we classified all experimental interventions in the included studies as CT, interventions nevertheless were clinically heterogeneous, with some delivered through paper and pencil and others via computerised platforms, some targeting single cognitive domains and others multiple domains simultaneously, and some focusing primarily on drill and practice while others employed a range of learning and performance strategies. The settings and doses at which the interventions were delivered were also diverse, with some delivered at home and others in community settings including daycare and hospital settings, and some delivered one or two times per week and others as many as five times per week. It is therefore more appropriate to think of the interventions included in the current review as consisting of a class or family of interventions with some shared features and, accordingly, that the interventions do not measure the exact same effect; this is reflected in our decision to conduct a random‐effects meta‐analysis, which is more suitable under these circumstances (Deeks 2017). Although observed clinical heterogeneity is most likely responsible for some of the observed statistical heterogeneity in effect estimates from individual trials, our pre‐specified subgroup analyses, carried out in cases where we found at least moderate heterogeneity and a sufficient number of available trials, did not reveal strong evidence of differences that would justify separate meta‐analyses for different subgroups.

Outcomes and measures

Our review focused on a large number of primary and secondary outcomes for the person with dementia and for their caregivers, and we made a distinction between outcomes immediately post intervention and outcomes reported in the medium term (3 to 12 months post treatment). Across studies, outcomes were evaluated with over 200 measures; however, in many cases, a given measure was counted multiple times owing to minor differences in naming across countries or in versions of the instrument, or the provision of insufficient detail to determine which exact measure was used. When studies provided individual subtest scores from test batteries or global indices, we counted each subtest as a measure. In some cases, studies used unpublished tests developed for the purpose of that particular study. In many cases, it was difficult to classify cognitive measures into a single cognitive domain; many other studies used multiple measures of the same cognitive outcome domain, and we followed our pre‐specified plan (see Unit of analysis issues under Methods) in selecting measures for meta‐analysis. Although we acknowledge that this method has limitations and may have not always resulted in an optimal assessment of a given cognitive domain, we adopted the procedure to reduce the likelihood of bias introduced by selecting a measure on the basis of effect size.

Our first primary outcome ‐ change in global (composite) cognitive ability immediately post treatment ‐ was evaluated by 33 studies with a total of 1914 participants. In contrast, our second primary outcome ‐ change in disease progression in the medium term, an outcome that may be of greater importance to people with dementia and decision‐makers ‐ was evaluated in only two studies with a total of 98 participants, using a dementia severity rating scale. Although researchers found a moderate effect of CT relative to control treatment in relation to change in clinical disease severity, our certainty in this finding is very low. Many other important outcomes (e.g. change in caregiver mood, burden, or quality of life in the medium term) were evaluated by a single study so that no meta‐analysis could be performed; other outcomes (e.g. changes in behavioural and psychological symptoms in the medium term, change in caregiver mood post treatment) were evaluated by a very small number of studies, or were not evaluated at all. It is important to note that although we were able to perform a meta‐analysis based on large numbers of studies and participants for the primary outcome of global cognition, and despite our findings suggesting at least a small to moderate effect of CT relative to control treatments, the extent to which observed cognitive benefits are clinically meaningful remains unclear. Indeed, we found no evidence that CT leads to changes in people's capacity to perform activities of daily living immediately post treatment or in the medium term, although the quality of the evidence was low and findings are therefore inconclusive.

Intervention fidelity and participant adherence

Adherence to a prescribed intervention protocol is frequently a barrier for lifestyle interventions, particularly unsupervised, self‐delivered, home‐based interventions, and interpretation of the actual effects of interventions may be biased in the context of suboptimal adherence. However, reference to intervention adherence was made only by a small number of mostly recent studies (Amieva 2016; Brueggen 2017; Cahn‐Weiner 2003; Giovagnoli 2017; Kallio 2018; Trebbastoni 2018), and none of these prospectively defined 'adherence'. It is therefore difficult to know how similar or dissimilar adherences rates in different studies were, and to what extent effect estimates from individual studies were affected by issues of adherence. Similarly, with the exception of a small number of studies (Amieva 2016; Brueggen 2017; Cahn‐Weiner 2003; Giovagnoli 2017), no study made reference to taking steps associated with assessing or monitoring the fidelity with which an intervention was delivered, including whether or not any changes to the intervention protocol were made after recruitment commenced, whether a manualised intervention protocol was followed, or whether those delivering the intervention underwent specific training. Lack of adequate measures to ensure fidelity has implications for the replicability of behavioural intervention studies; it is therefore more difficult to know whether findings from a trial observed in one context are likely to be seen when the intervention is applied in another context.

Quality of the evidence

We used the GRADE approach to evaluate our confidence in study findings in relation to the main outcomes of this review, with grading incorporating the risk of bias in included studies, inconsistency and imprecision in the results, directness of the evidence, and publication bias (GRADE Handbook; GRADEpro GDT). In comparing CT with a control intervention, from the large number of outcomes assessed, we are highly confident only in our findings in relation to a single outcome immediately after treatment, namely, verbal category fluency. Our confidence in trial findings was moderate for several other outcomes immediately following the intervention, including our primary outcome of global cognition as measured by a composite score, as well as caregiver outcomes of burden of care and mood and well‐being. Our certainty in the findings of other outcomes, including our second primary outcome of clinical progression in the medium term, was very low. When CT was compared with an alternative treatment, we have moderate confidence in relation to our findings on change in participant mood, behavioural and psychological symptoms, and capacity for activities of daily living, as well as caregiver mood and well‐being at end of treatment. Our confidence in our findings on all other assessed outcomes at end of treatment and in the medium term is low or very low.

Risk of bias

Although we rated most studies as having high risk of bias in at least two domains, our approach to the classification of studies into 'high' and 'low' risk of bias for the purposes of subgroup analyses and grading of the evidence was relatively lenient and led to only seven studies rated as 'high‐risk' studies. However, with the exception of 'immediate memory' in our primary comparison (CT vs control intervention immediately post intervention), in which studies classified as 'high risk' were associated with smaller pooled effect estimates relative to 'low‐risk' studies, risk of bias did not seem to account for much of the heterogeneity in effect estimates. We pre‐defined 'high‐risk' studies in this review as studies that were rated as having 'high risk' on at least two critical domains. For our purposes, we defined critical domains as randomisation, blinding of outcome assessment, incomplete outcome data, and selective reporting. We acknowledge the importance of allocation concealment and blinding of participants and personnel. However, allocation concealment is rarely reported in CT trials to date, and most studies would be classified as having high risk if we classified this as a 'critical domain'. Similarly, blinding of those delivering the interventions is typically not possible in trials of this nature, and blinding of participants can be attempted only in trials with active control or alternative treatment.

Inconsistency

In relation to our primary outcomes, we downgraded 1 point evidence of our findings on global cognition for serious concerns regarding inconsistency when CT was compared to a control group immediately after the intervention, but we did not find these issues when CT was compared to an alternative treatment. For disease progression in the medium term, we again found no issues related to inconsistency. For most other outcomes, we rated inconsistency as not serious, typically due to relatively small heterogeneity or moderate heterogeneity, which was explained at least in part by at least one of the subgroup analyses. However, in many cases, we rated inconsistency as serious or very serious. For eight of the outcomes included in our primary comparison, we found very high heterogeneity in effect estimates (I² > 80%) and heterogeneity that was not generally well explained by any of the prognostic features included in our subgroup analyses.

Indirectness

Overall, outcomes evaluated in these studies and the measures used to assess them seem to be well mapped to our PICO question, so we did not downgrade the evidence in relation to any assessed outcomes for indirectness. Although measures of cognition and cognitive test scores do not directly correspond with quality of performance of daily activities, cognitive scores based on psychometric evaluation are considered a true reflection of one's objective cognitive abilities. Similarly, in measuring clinical disease status, most studies that reported this outcome did so with widely used clinical staging measures such as the Clinical Dementia Rating Scale (e.g. Mapelli 2013) or the Rapid Disability Rating Scale (e.g. Quintana Hernandez 2014), while none of the included studies used possibly more direct indications of clinical progression, such as admission to residential care. Unlike changes in mood, cognition, or behavioural symptoms, clinical disease progression is a longer‐term outcome, in the context of mild dementia in particular, and assessment of this outcome requires large, adequately powered trials providing long‐term follow‐up.

Imprecision

For our primary comparison (CT vs control at end of treatment), we had no major concerns related to imprecision in the effect estimate of our primary outcome, namely, global cognition. However, we had serious or very serious concerns in relation to imprecision regarding most secondary outcomes, including all non‐cognitive outcomes and several specific cognitive domains. These concerns were mainly due to large confidence intervals of effect estimates that included potentially meaningful effects, no effects, and effects favouring the control condition. In our additional comparisons (CT vs control in the medium term, and CT vs alternative treatment at end of treatment and in the medium term), we found that imprecision was a serious or a very serious concern in relation to all outcomes, including our primary outcome of clinical progression in the medium term. For these additional comparisons, imprecision was a concern due to the much smaller number of participants on which many of the effect estimates were based, as well as the large confidence intervals of these estimates. Hence, in relation to many outcomes of interest, we found that primary studies sometimes disagreed not only on the size, but also on the direction, of effects of CT.

Publication bias

Our search results suggested that several trials registered in recent years and interventions undertaken as part of student research projects might never have been published, raising some concern about positive publication bias. However, with the exception of a few outcomes (e.g. change in immediate and delayed memory, verbal letter fluency, executive function at end of treatment), we could not ascertain the presence of publication bias with much confidence on the basis of visual inspection of funnel plots for each outcome. In addition, asymmetry in funnel plots may be caused by factors other than publication bias, so we decided to take a conservative approach; we downgraded the evidence for suspected publication bias only in cases in which asymmetry in the funnel plot was reasonably evident, and a minimum of 10 studies had assessed the relevant outcome. Our approach may have resulted in an underestimation of the true extent of concerns related to the presence of publication bias.

Potential biases in the review process

We conducted a thorough search for articles and performed a rigorous screening procedure and risk of bias assessments, conducted independently by two review authors, with disagreements resolved by a third reviewer. Similarly, grading of the evidence was also completed by two of the review authors, who resolved disagreements by discussion until consensus was reached. The review team includes researchers at all stages of their professional career and with various levels of dementia‐specific expertise, further reducing the likelihood of systematic bias in the review process. None of the included studies were conducted by one of the review authors, and no conflicts of interest have been identified. Although unlikely, we cannot rule out the possibility that difficulties associated with forming an accurate judgement in relation to some areas of potential bias might have led to a systematic overestimation (e.g. risk of selection bias due to lack of allocation concealment) or underestimation (e.g. publication bias) of the actual risk of bias.

Agreements and disagreements with other studies or reviews

In recent years, numerous systematic reviews with and without meta‐analyses of cognition‐oriented treatments for older adults with and without dementia have been completed, and we have recently reviewed this large body of work (Malmberg Gavelin). Of particular relevance to the current review are several recent reviews focused on CT for persons with dementia, including Alves 2013, Bahar‐Fuchs 2013, Huntley 2015, Folkerts 2017, and Hill 2017. Alves and colleagues conducted a systematic review with a meta‐analysis on four studies that met their inclusion criteria (three of which were included in the present review; Cahn‐Weiner 2003Davis 2001Heiss 1993). Closer inspection suggested that the fourth study included in that review was of cognitive stimulation therapy and therefore would not meet criteria for the current review. Alves found that the intervention was beneficial, relative to a control intervention, only in relation to global cognition at end of treatment, as reflected in the Mini Mental State Examination (MMSE). Although the effect was large, the meta‐analysis was based on only three studies (one of which was the cognitive stimulation study) and 104 participants, so precision was likely low. The other estimates were generally based on one or two studies only, so the conclusions drawn were naturally very limited. More recently, the Huntley 2015 systematic review conducted a meta‐analysis of cognition‐oriented treatment trials for people with dementia and provided separate effect estimates for global cognition from four studies classified as CT (all of which were included in the present review) and seven studies classified as mixed CT and stimulation (three of which were included in the current review and coded as 'augmented CT'). Based on three studies, those review authors did not find strong evidence of an effect of CT relative to an active control condition on global cognition, as reflected on the MMSE (standardised mean difference (SMD) 0.22, 95% confidence interval (CI) ‐0.74 to 1.18). Findings also suggested there were no benefits of mixed CT and stimulation on global cognition, whether compared with a passive (SMD 0.44, 95% CI ‐0.56 to 1.46) or an active control treatment (SMD 0.25, 95% CI ‐0.18 to 0.68). In contrast, in the current review, change in global cognition as reflected by a composite score and on the basis of a screening measure (such as the MMSE) was greater at end of treatment in the CT group relative to the control condition, based on 20 studies, and effect estimates were similar in magnitude when active (k = 8; SMD 0.61) and passive (k = 12; SMD 0.69) control conditions were directly contrasted. It is interesting to note that results of the current review show a trend suggesting that although 'traditional' CT (k = 13) is associated with large effect relative to control treatment (SMD 0.83, 95% CI 0.30 to 1.39), 'augmented' CT (k = 7) is associated with a relatively small effect estimate (SMD 0.25, 95% CI ‐0.21 to 0.70), and differences between the two subgroups approached significance (Chi² = 2.68, df = 1, P = 0.10). Folkerts 2017 recently reported a systematic review with meta‐analysis of cognition‐oriented treatments for people with dementia living in residential care; six trials were classified as CT, two of which contributed data for meta‐analysis (both studies ‐ Kawashima 2005; Mapelli 2013 ‐ are included in the current review). On the basis of these two studies with 47 participants, these review authors found that CT was superior to passive control treatment in relation to global cognition (SMD 1.16, 95% CI 0.52 to 1.79) ‐ a finding that is likely to be very imprecise due to the small number of participants on which it is based, but that is nonetheless in agreement with the findings of the current review. Finally, Hill 2017, a comprehensive systematic review, performed meta‐analysis of computerised CT for people with mild cognitive impairment (MCI) and dementia, and reported effects separately for each population. Based on a meta‐analysis of 12 studies with a total of 389 participants, that review found a small effect of CT relative to a control treatment on global cognition at end of treatment (SMD 0.26, 95% CI 0.01 to 0.52) but found no effects in other cognitive domains.

Study flow diagram.
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Figure 1

Study flow diagram.

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Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
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Figure 2

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

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Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
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Figure 3

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

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Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.1 Change in a global measure of cognition (composite).
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Figure 4

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.1 Change in a global measure of cognition (composite).

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Funnel plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.1 Change in a global measure of cognition (composite).
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Figure 5

Funnel plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.1 Change in a global measure of cognition (composite).

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Forest plot of comparison: 3 Cognitive training vs alternative treatment immediately post intervention, outcome: 3.1 Change in a global measure of cognition (composite).
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Figure 6

Forest plot of comparison: 3 Cognitive training vs alternative treatment immediately post intervention, outcome: 3.1 Change in a global measure of cognition (composite).

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Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.3 Change in a global measure of cognition.
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Figure 7

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.3 Change in a global measure of cognition.

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Forest plot of comparison: 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), outcome: 2.5 Change in disease progression.
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Figure 8

Forest plot of comparison: 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), outcome: 2.5 Change in disease progression.

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Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.6 Change in delayed memory.
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Figure 9

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.6 Change in delayed memory.

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Forest plot of comparison: 6 Cognitive training vs control immediately post intervention ‐ intervention dose, outcome: 6.9 Change in verbal letter fluency.
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Figure 10

Forest plot of comparison: 6 Cognitive training vs control immediately post intervention ‐ intervention dose, outcome: 6.9 Change in verbal letter fluency.

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Forest plot of comparison: 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), outcome: 9.12 Change in verbal category fluency.
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Figure 11

Forest plot of comparison: 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), outcome: 9.12 Change in verbal category fluency.

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Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.16 Change in participants' mood.
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Figure 12

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.16 Change in participants' mood.

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Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.17 Change in capacity for activities of daily living.
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Figure 13

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.17 Change in capacity for activities of daily living.

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Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.20 Participant burden (retention rates).
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Figure 14

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.20 Participant burden (retention rates).

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Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.23 Change in mood and well‐being (CAREGIVER).
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Figure 15

Forest plot of comparison: 1 Cognitive training vs control immediately post intervention, outcome: 1.23 Change in mood and well‐being (CAREGIVER).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 1 Change in a global measure of cognition (composite).
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Analysis 1.1

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 1 Change in a global measure of cognition (composite).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 2 Change in a global measure of cognition (composite)_zero correlation.
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Analysis 1.2

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 2 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 3 Change in a global measure of cognition.
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Analysis 1.3

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 3 Change in a global measure of cognition.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 4 Change in a global measure of cognition_zero correlation.
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Analysis 1.4

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 4 Change in a global measure of cognition_zero correlation.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 5 Change in disease progression.
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Analysis 1.5

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 5 Change in disease progression.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 6 Change in delayed memory.
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Analysis 1.6

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 6 Change in delayed memory.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 7 Change in immediate memory.
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Analysis 1.7

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 7 Change in immediate memory.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 8 Change in attention and working memory.
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Analysis 1.8

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 8 Change in attention and working memory.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 9 Change in language (naming).
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Analysis 1.9

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 9 Change in language (naming).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 10 Change in verbal letter fluency.
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Analysis 1.10

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 10 Change in verbal letter fluency.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 11 Change in verbal category fluency.
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Analysis 1.11

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 11 Change in verbal category fluency.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 12 Change in executive function.
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Analysis 1.12

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 12 Change in executive function.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 13 Change in speed of information processing.
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Analysis 1.13

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 13 Change in speed of information processing.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 14 Change in meta cognition (self‐reported).
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Analysis 1.14

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 14 Change in meta cognition (self‐reported).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 15 Change in meta cognition (informant‐reported).
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Analysis 1.15

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 15 Change in meta cognition (informant‐reported).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 16 Change in participants' mood.
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Analysis 1.16

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 16 Change in participants' mood.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 17 Change in capacity for activities of daily living.
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Analysis 1.17

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 17 Change in capacity for activities of daily living.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 18 Change in general health and quality of life.
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Analysis 1.18

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 18 Change in general health and quality of life.

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 19 Change in behavioural and psychological symptoms of dementia (BPSD).
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Analysis 1.19

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 19 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 20 Participant burden (retention rates).
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Analysis 1.20

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 20 Participant burden (retention rates).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 21 Change in burden of care (CAREGIVER).
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Analysis 1.21

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 21 Change in burden of care (CAREGIVER).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 22 Change in quality of life (CAREGIVER).
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Analysis 1.22

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 22 Change in quality of life (CAREGIVER).

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Comparison 1 Cognitive training vs control immediately post intervention, Outcome 23 Change in mood and well‐being (CAREGIVER).
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Analysis 1.23

Comparison 1 Cognitive training vs control immediately post intervention, Outcome 23 Change in mood and well‐being (CAREGIVER).

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 1 Change in a global measure of cognition (composite).
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Analysis 2.1

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 1 Change in a global measure of cognition (composite).

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 2 Change in a global measure of cognition (composite)_zero correlation.
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Analysis 2.2

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 2 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 3 Change in a global measure of cognition.
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Analysis 2.3

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 3 Change in a global measure of cognition.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 4 Change in a global measure of cognition (zero correlation).
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Analysis 2.4

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 4 Change in a global measure of cognition (zero correlation).

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 5 Change in disease progression.
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Analysis 2.5

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 5 Change in disease progression.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 6 Change in disease progression (zero correlation).
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Analysis 2.6

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 6 Change in disease progression (zero correlation).

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 7 Change in delayed memory.
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Analysis 2.7

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 7 Change in delayed memory.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 8 Change in immediate memory.
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Analysis 2.8

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 8 Change in immediate memory.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 9 Change in attention and working memory.
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Analysis 2.9

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 9 Change in attention and working memory.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 10 Change in language (naming).
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Analysis 2.10

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 10 Change in language (naming).

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 11 Change in verbal letter fluency.
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Analysis 2.11

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 11 Change in verbal letter fluency.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 12 Change in verbal category fluency.
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Analysis 2.12

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 12 Change in verbal category fluency.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 13 Change in executive function.
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Analysis 2.13

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 13 Change in executive function.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 14 Change in speed of information processing.
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Analysis 2.14

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 14 Change in speed of information processing.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 15 Change in meta cognition (self‐reported).
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Analysis 2.15

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 15 Change in meta cognition (self‐reported).

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 16 Change in meta cognition (informant‐reported).
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Analysis 2.16

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 16 Change in meta cognition (informant‐reported).

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 17 Change in participants' mood.
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Analysis 2.17

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 17 Change in participants' mood.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 18 Change in capacity for activities of daily living.
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Analysis 2.18

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 18 Change in capacity for activities of daily living.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 19 Change in general health and quality of life.
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Analysis 2.19

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 19 Change in general health and quality of life.

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Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 20 Change in behavioural and psychological symptoms of dementia (BPSD).
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Analysis 2.20

Comparison 2 Cognitive training vs control in the medium term (3 to 12 months post intervention), Outcome 20 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 1 Change in a global measure of cognition (composite).
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Analysis 3.1

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 1 Change in a global measure of cognition (composite).

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 2 Change in a global measure of cognition (composite)_zero correlation.
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Analysis 3.2

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 2 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 3 Change in a global measure of cognition.
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Analysis 3.3

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 3 Change in a global measure of cognition.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 4 Change in a global measure of cognition_zero correlation.
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Analysis 3.4

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 4 Change in a global measure of cognition_zero correlation.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 5 Change in disease progression.
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Analysis 3.5

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 5 Change in disease progression.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 6 Change in delayed memory.
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Analysis 3.6

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 6 Change in delayed memory.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 7 Change in immediate memory.
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Analysis 3.7

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 7 Change in immediate memory.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 8 Change in attention and working memory.
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Analysis 3.8

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 8 Change in attention and working memory.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 9 Change in language (naming).
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Analysis 3.9

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 9 Change in language (naming).

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 10 Change in verbal letter fluency.
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Analysis 3.10

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 10 Change in verbal letter fluency.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 11 Change in verbal category fluency.
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Analysis 3.11

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 11 Change in verbal category fluency.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 12 Change in executive function.
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Analysis 3.12

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 12 Change in executive function.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 13 Change in speed of information processing.
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Analysis 3.13

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 13 Change in speed of information processing.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 16 Change in participants' mood.
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Analysis 3.16

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 16 Change in participants' mood.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 17 Change in capacity for activities of daily living.
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Analysis 3.17

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 17 Change in capacity for activities of daily living.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 18 Change in general health and quality of life.
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Analysis 3.18

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 18 Change in general health and quality of life.

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 19 Change in behavioural and psychological symptoms of dementia (BPSD).
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Analysis 3.19

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 19 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 20 Participant burden (retention rates).
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Analysis 3.20

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 20 Participant burden (retention rates).

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 21 Change in burden of care (CAREGIVER).
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Analysis 3.21

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 21 Change in burden of care (CAREGIVER).

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 22 Change in quality of life (CAREGIVER).
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Analysis 3.22

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 22 Change in quality of life (CAREGIVER).

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Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 23 Change in mood and well‐being (CAREGIVER).
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Analysis 3.23

Comparison 3 Cognitive training vs alternative treatment immediately post intervention, Outcome 23 Change in mood and well‐being (CAREGIVER).

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 1 Change in a global measure of cognition (composite).
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Analysis 4.1

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 1 Change in a global measure of cognition (composite).

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 2 Change in a global measure of cognition (composite)_zero correlation.
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Analysis 4.2

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 2 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 3 Change in a global measure of cognition.
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Analysis 4.3

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 3 Change in a global measure of cognition.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 4.6

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 6 Change in delayed memory.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 7 Change in immediate memory.
Figures and Tables -
Analysis 4.7

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 7 Change in immediate memory.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 8 Change in attention and working memory.
Figures and Tables -
Analysis 4.8

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 8 Change in attention and working memory.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 9 Change in language (naming).
Figures and Tables -
Analysis 4.9

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 9 Change in language (naming).

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 10 Change in verbal letter fluency.
Figures and Tables -
Analysis 4.10

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 10 Change in verbal letter fluency.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 11 Change in verbal category fluency.
Figures and Tables -
Analysis 4.11

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 11 Change in verbal category fluency.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 12 Change in executive function.
Figures and Tables -
Analysis 4.12

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 12 Change in executive function.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 13 Change in speed of information processing.
Figures and Tables -
Analysis 4.13

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 13 Change in speed of information processing.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 16 Change in participants' mood.
Figures and Tables -
Analysis 4.16

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 16 Change in participants' mood.

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Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 18 Change in general health and quality of life.
Figures and Tables -
Analysis 4.18

Comparison 4 Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention), Outcome 18 Change in general health and quality of life.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 5.1

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 1 Change in a global measure of cognition.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 2 Change in a global measure of cognition_zero correlation.
Figures and Tables -
Analysis 5.2

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 2 Change in a global measure of cognition_zero correlation.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 5.3

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 3 Change in a global measure of cognition (composite).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 5.4

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 5 Change in immediate memory.
Figures and Tables -
Analysis 5.5

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 5 Change in immediate memory.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 5.6

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 6 Change in delayed memory.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 7 Change in attention and working memory.
Figures and Tables -
Analysis 5.7

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 7 Change in attention and working memory.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 8 Change in language (naming).
Figures and Tables -
Analysis 5.8

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 8 Change in language (naming).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 9 Change in verbal letter fluency.
Figures and Tables -
Analysis 5.9

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 9 Change in verbal letter fluency.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 10 Change in speed of information processing.
Figures and Tables -
Analysis 5.10

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 10 Change in speed of information processing.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 11 Change in executive function.
Figures and Tables -
Analysis 5.11

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 11 Change in executive function.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 12 Change in verbal category fluency.
Figures and Tables -
Analysis 5.12

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 12 Change in verbal category fluency.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 13 Change in meta cognition (self‐reported).
Figures and Tables -
Analysis 5.13

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 13 Change in meta cognition (self‐reported).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 14 Change in meta cognition (informant‐reported).
Figures and Tables -
Analysis 5.14

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 14 Change in meta cognition (informant‐reported).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 15 Change in participants' mood.
Figures and Tables -
Analysis 5.15

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 15 Change in participants' mood.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 16 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 5.16

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 16 Change in capacity for activities of daily living.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 17 Change in general health and quality of life.
Figures and Tables -
Analysis 5.17

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 17 Change in general health and quality of life.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 5.18

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 19 Change in disease progression.
Figures and Tables -
Analysis 5.19

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 19 Change in disease progression.

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 20 Change in burden of care (CAREGIVER).
Figures and Tables -
Analysis 5.20

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 20 Change in burden of care (CAREGIVER).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 21 Change in quality of life (CAREGIVER).
Figures and Tables -
Analysis 5.21

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 21 Change in quality of life (CAREGIVER).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 22 Change in mood and well‐being (CAREGIVER).
Figures and Tables -
Analysis 5.22

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 22 Change in mood and well‐being (CAREGIVER).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 23 Participant burden (retention rates).
Figures and Tables -
Analysis 5.23

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 23 Participant burden (retention rates).

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Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 24 Change in general health and quality of life.
Figures and Tables -
Analysis 5.24

Comparison 5 Cognitive training vs control immediately post intervention ‐ risk of bias, Outcome 24 Change in general health and quality of life.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 6.1

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 1 Change in a global measure of cognition.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 2 Change in a global measure of cognition_zero correlation.
Figures and Tables -
Analysis 6.2

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 2 Change in a global measure of cognition_zero correlation.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 6.3

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 3 Change in a global measure of cognition (composite).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 6.4

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 5 Change in immediate memory.
Figures and Tables -
Analysis 6.5

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 5 Change in immediate memory.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 6.6

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 6 Change in delayed memory.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 7 Change in attention and working memory.
Figures and Tables -
Analysis 6.7

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 7 Change in attention and working memory.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 8 Change in language (naming).
Figures and Tables -
Analysis 6.8

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 8 Change in language (naming).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 9 Change in verbal letter fluency.
Figures and Tables -
Analysis 6.9

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 9 Change in verbal letter fluency.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 10 Change in speed of information processing.
Figures and Tables -
Analysis 6.10

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 10 Change in speed of information processing.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 11 Change in executive function.
Figures and Tables -
Analysis 6.11

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 11 Change in executive function.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 12 Change in verbal category fluency.
Figures and Tables -
Analysis 6.12

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 12 Change in verbal category fluency.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 13 Change in meta cognition (self‐reported).
Figures and Tables -
Analysis 6.13

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 13 Change in meta cognition (self‐reported).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 14 Change in meta cognition (informant‐reported).
Figures and Tables -
Analysis 6.14

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 14 Change in meta cognition (informant‐reported).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 15 Change in participants' mood.
Figures and Tables -
Analysis 6.15

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 15 Change in participants' mood.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 16 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 6.16

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 16 Change in capacity for activities of daily living.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 17 Change in disease progression.
Figures and Tables -
Analysis 6.17

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 17 Change in disease progression.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 6.18

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 19 Change in attention and working memory.
Figures and Tables -
Analysis 6.19

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 19 Change in attention and working memory.

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 20 Change in burden of care (CAREGIVER).
Figures and Tables -
Analysis 6.20

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 20 Change in burden of care (CAREGIVER).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 21 Change in quality of life (CAREGIVER).
Figures and Tables -
Analysis 6.21

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 21 Change in quality of life (CAREGIVER).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 22 Change in mood and well‐being (CAREGIVER).
Figures and Tables -
Analysis 6.22

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 22 Change in mood and well‐being (CAREGIVER).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 23 Participant burden (retention rates).
Figures and Tables -
Analysis 6.23

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 23 Participant burden (retention rates).

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Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 24 Change in general health and quality of life.
Figures and Tables -
Analysis 6.24

Comparison 6 Cognitive training vs control immediately post intervention ‐ intervention dose, Outcome 24 Change in general health and quality of life.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 7.1

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 1 Change in a global measure of cognition.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 2 Change in a global measure of cognition_zero correlation.
Figures and Tables -
Analysis 7.2

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 2 Change in a global measure of cognition_zero correlation.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 7.3

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 3 Change in a global measure of cognition (composite).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 7.4

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 5 Change in immediate memory.
Figures and Tables -
Analysis 7.5

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 5 Change in immediate memory.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 7.6

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 6 Change in delayed memory.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 7 Change in attention and working memory.
Figures and Tables -
Analysis 7.7

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 7 Change in attention and working memory.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 8 Change in language (naming).
Figures and Tables -
Analysis 7.8

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 8 Change in language (naming).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 9 Change in verbal letter fluency.
Figures and Tables -
Analysis 7.9

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 9 Change in verbal letter fluency.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 10 Change in speed of information processing.
Figures and Tables -
Analysis 7.10

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 10 Change in speed of information processing.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 11 Change in executive function.
Figures and Tables -
Analysis 7.11

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 11 Change in executive function.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 12 Change in verbal category fluency.
Figures and Tables -
Analysis 7.12

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 12 Change in verbal category fluency.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 13 Change in meta cognition (self‐reported).
Figures and Tables -
Analysis 7.13

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 13 Change in meta cognition (self‐reported).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 14 Change in meta cognition (informant‐reported).
Figures and Tables -
Analysis 7.14

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 14 Change in meta cognition (informant‐reported).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 15 Change in participants' mood.
Figures and Tables -
Analysis 7.15

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 15 Change in participants' mood.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 16 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 7.16

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 16 Change in capacity for activities of daily living.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 17 Change in disease progression.
Figures and Tables -
Analysis 7.17

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 17 Change in disease progression.

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 7.18

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 19 Participant burden (retention rates).
Figures and Tables -
Analysis 7.19

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 19 Participant burden (retention rates).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 20 Change in burden of care (CAREGIVER).
Figures and Tables -
Analysis 7.20

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 20 Change in burden of care (CAREGIVER).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 21 Change in quality of life (CAREGIVER).
Figures and Tables -
Analysis 7.21

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 21 Change in quality of life (CAREGIVER).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 22 Change in mood and well‐being (CAREGIVER).
Figures and Tables -
Analysis 7.22

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 22 Change in mood and well‐being (CAREGIVER).

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Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 23 Change in general health and quality of life.
Figures and Tables -
Analysis 7.23

Comparison 7 Cognitive training vs control immediately post intervention ‐ intervention duration, Outcome 23 Change in general health and quality of life.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 8.1

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 1 Change in a global measure of cognition.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 2 Change in a global measure of cognition_zero correlation.
Figures and Tables -
Analysis 8.2

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 2 Change in a global measure of cognition_zero correlation.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 8.3

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 3 Change in a global measure of cognition (composite).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 8.4

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 5 Change in immediate memory.
Figures and Tables -
Analysis 8.5

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 5 Change in immediate memory.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 8.6

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 6 Change in delayed memory.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 7 Change in attention and working memory.
Figures and Tables -
Analysis 8.7

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 7 Change in attention and working memory.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 8 Change in language (naming).
Figures and Tables -
Analysis 8.8

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 8 Change in language (naming).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 9 Change in verbal letter fluency.
Figures and Tables -
Analysis 8.9

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 9 Change in verbal letter fluency.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 10 Change in speed of information processing.
Figures and Tables -
Analysis 8.10

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 10 Change in speed of information processing.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 11 Change in executive function.
Figures and Tables -
Analysis 8.11

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 11 Change in executive function.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 12 Change in verbal category fluency.
Figures and Tables -
Analysis 8.12

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 12 Change in verbal category fluency.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 13 Change in meta cognition (self‐reported).
Figures and Tables -
Analysis 8.13

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 13 Change in meta cognition (self‐reported).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 14 Change in meta cognition (informant‐reported).
Figures and Tables -
Analysis 8.14

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 14 Change in meta cognition (informant‐reported).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 15 Change in participants' mood.
Figures and Tables -
Analysis 8.15

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 15 Change in participants' mood.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 16 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 8.16

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 16 Change in capacity for activities of daily living.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 17 Change in disease progression.
Figures and Tables -
Analysis 8.17

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 17 Change in disease progression.

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 8.18

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 19 Participant burden (retention rates).
Figures and Tables -
Analysis 8.19

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 19 Participant burden (retention rates).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 20 Change in burden of care (CAREGIVER).
Figures and Tables -
Analysis 8.20

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 20 Change in burden of care (CAREGIVER).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 21 Change in quality of life (CAREGIVER).
Figures and Tables -
Analysis 8.21

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 21 Change in quality of life (CAREGIVER).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 22 Change in mood and well‐being (CAREGIVER).
Figures and Tables -
Analysis 8.22

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 22 Change in mood and well‐being (CAREGIVER).

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Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 23 Change in general health and quality of life.
Figures and Tables -
Analysis 8.23

Comparison 8 Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 23 Change in general health and quality of life.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 9.1

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 1 Change in a global measure of cognition.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 2 Change in a global measure of cognition_zero correlation.
Figures and Tables -
Analysis 9.2

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 2 Change in a global measure of cognition_zero correlation.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 9.3

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 3 Change in a global measure of cognition (composite).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 9.4

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 5 Change in immediate memory.
Figures and Tables -
Analysis 9.5

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 5 Change in immediate memory.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 9.6

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 6 Change in delayed memory.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 7 Change in attention and working memory.
Figures and Tables -
Analysis 9.7

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 7 Change in attention and working memory.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 8 Change in language (naming).
Figures and Tables -
Analysis 9.8

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 8 Change in language (naming).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 9 Change in verbal letter fluency.
Figures and Tables -
Analysis 9.9

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 9 Change in verbal letter fluency.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 10 Change in speed of information processing.
Figures and Tables -
Analysis 9.10

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 10 Change in speed of information processing.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 11 Change in executive function.
Figures and Tables -
Analysis 9.11

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 11 Change in executive function.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 12 Change in verbal category fluency.
Figures and Tables -
Analysis 9.12

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 12 Change in verbal category fluency.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 13 Change in meta cognition (self‐reported).
Figures and Tables -
Analysis 9.13

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 13 Change in meta cognition (self‐reported).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 14 Change in meta cognition (informant‐reported).
Figures and Tables -
Analysis 9.14

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 14 Change in meta cognition (informant‐reported).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 15 Change in participants' mood.
Figures and Tables -
Analysis 9.15

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 15 Change in participants' mood.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 16 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 9.16

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 16 Change in capacity for activities of daily living.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 17 Change in disease progression.
Figures and Tables -
Analysis 9.17

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 17 Change in disease progression.

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 9.18

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 19 Participant burden (retention rates).
Figures and Tables -
Analysis 9.19

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 19 Participant burden (retention rates).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 20 Change in burden of care (CAREGIVER).
Figures and Tables -
Analysis 9.20

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 20 Change in burden of care (CAREGIVER).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 21 Change in quality of life (CAREGIVER).
Figures and Tables -
Analysis 9.21

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 21 Change in quality of life (CAREGIVER).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 22 Change in mood and well‐being (CAREGIVER).
Figures and Tables -
Analysis 9.22

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 22 Change in mood and well‐being (CAREGIVER).

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Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 23 Change in general health and quality of life.
Figures and Tables -
Analysis 9.23

Comparison 9 Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain), Outcome 23 Change in general health and quality of life.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 10.1

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 1 Change in a global measure of cognition.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 2 Change in a global measure of cognition_zero correlation.
Figures and Tables -
Analysis 10.2

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 2 Change in a global measure of cognition_zero correlation.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 10.3

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 3 Change in a global measure of cognition (composite).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 10.4

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 5 Change in immediate memory.
Figures and Tables -
Analysis 10.5

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 5 Change in immediate memory.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 10.6

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 6 Change in delayed memory.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 7 Change in attention and working memory.
Figures and Tables -
Analysis 10.7

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 7 Change in attention and working memory.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 8 Change in language (naming).
Figures and Tables -
Analysis 10.8

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 8 Change in language (naming).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 9 Change in verbal letter fluency.
Figures and Tables -
Analysis 10.9

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 9 Change in verbal letter fluency.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 10 Change in speed of information processing.
Figures and Tables -
Analysis 10.10

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 10 Change in speed of information processing.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 11 Change in executive function.
Figures and Tables -
Analysis 10.11

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 11 Change in executive function.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 12 Change in verbal category fluency.
Figures and Tables -
Analysis 10.12

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 12 Change in verbal category fluency.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 13 Change in meta cognition (self‐reported).
Figures and Tables -
Analysis 10.13

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 13 Change in meta cognition (self‐reported).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 14 Change in meta cognition (informant‐reported).
Figures and Tables -
Analysis 10.14

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 14 Change in meta cognition (informant‐reported).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 15 Change in participants' mood.
Figures and Tables -
Analysis 10.15

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 15 Change in participants' mood.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 16 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 10.16

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 16 Change in capacity for activities of daily living.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 17 Change in disease progression.
Figures and Tables -
Analysis 10.17

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 17 Change in disease progression.

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 10.18

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 18 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 19 Participant burden (retention rates).
Figures and Tables -
Analysis 10.19

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 19 Participant burden (retention rates).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 20 Change in burden of care (CAREGIVER).
Figures and Tables -
Analysis 10.20

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 20 Change in burden of care (CAREGIVER).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 21 Change in quality of life (CAREGIVER).
Figures and Tables -
Analysis 10.21

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 21 Change in quality of life (CAREGIVER).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 22 Change in mood and well‐being (CAREGIVER).
Figures and Tables -
Analysis 10.22

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 22 Change in mood and well‐being (CAREGIVER).

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Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 23 Change in general health and quality of life.
Figures and Tables -
Analysis 10.23

Comparison 10 Cognitive training vs control immediately post intervention ‐ type of control (passive vs active), Outcome 23 Change in general health and quality of life.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 11.1

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 1 Change in a global measure of cognition.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 2 Change in a global measure of cognition_zero correlation.
Figures and Tables -
Analysis 11.2

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 2 Change in a global measure of cognition_zero correlation.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 11.3

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 3 Change in a global measure of cognition (composite).

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 11.4

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 5 Change in immediate memory.
Figures and Tables -
Analysis 11.5

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 5 Change in immediate memory.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 11.6

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 6 Change in delayed memory.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 7 Change in attention and working memory.
Figures and Tables -
Analysis 11.7

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 7 Change in attention and working memory.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 8 Change in language (naming).
Figures and Tables -
Analysis 11.8

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 8 Change in language (naming).

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 9 Change in verbal letter fluency.
Figures and Tables -
Analysis 11.9

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 9 Change in verbal letter fluency.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 10 Change in verbal category fluency.
Figures and Tables -
Analysis 11.10

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 10 Change in verbal category fluency.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 11 Change in executive function.
Figures and Tables -
Analysis 11.11

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 11 Change in executive function.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 14 Change in participants' mood.
Figures and Tables -
Analysis 11.14

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 14 Change in participants' mood.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 15 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 11.15

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 15 Change in capacity for activities of daily living.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 16 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 11.16

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 16 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 17 Change in disease progression.
Figures and Tables -
Analysis 11.17

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 17 Change in disease progression.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 18 Participant burden (retention rates).
Figures and Tables -
Analysis 11.18

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 18 Participant burden (retention rates).

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 19 Change in mood and well‐being (CAREGIVER).
Figures and Tables -
Analysis 11.19

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 19 Change in mood and well‐being (CAREGIVER).

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 20 Change in burden of care (CAREGIVER).
Figures and Tables -
Analysis 11.20

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 20 Change in burden of care (CAREGIVER).

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 21 Change in quality of life (CAREGIVER).
Figures and Tables -
Analysis 11.21

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 21 Change in quality of life (CAREGIVER).

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 22 Change in speed of information processing.
Figures and Tables -
Analysis 11.22

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 22 Change in speed of information processing.

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Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 23 Change in general health and quality of life.
Figures and Tables -
Analysis 11.23

Comparison 11 Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose, Outcome 23 Change in general health and quality of life.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 12.1

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 1 Change in a global measure of cognition.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 2 Change in a global measure of cognition_zero correlation.
Figures and Tables -
Analysis 12.2

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 2 Change in a global measure of cognition_zero correlation.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 12.3

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 3 Change in a global measure of cognition (composite).

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 12.4

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 5 Change in immediate memory.
Figures and Tables -
Analysis 12.5

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 5 Change in immediate memory.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 6 Change in delayed memory.
Figures and Tables -
Analysis 12.6

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 6 Change in delayed memory.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 7 Change in attention and working memory.
Figures and Tables -
Analysis 12.7

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 7 Change in attention and working memory.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 8 Change in language (naming).
Figures and Tables -
Analysis 12.8

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 8 Change in language (naming).

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 9 Change in verbal letter fluency.
Figures and Tables -
Analysis 12.9

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 9 Change in verbal letter fluency.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 10 Change in verbal category fluency.
Figures and Tables -
Analysis 12.10

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 10 Change in verbal category fluency.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 11 Change in executive function.
Figures and Tables -
Analysis 12.11

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 11 Change in executive function.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 14 Change in participants' mood.
Figures and Tables -
Analysis 12.14

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 14 Change in participants' mood.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 15 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 12.15

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 15 Change in capacity for activities of daily living.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 16 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 12.16

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 16 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 17 Change in disease progression.
Figures and Tables -
Analysis 12.17

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 17 Change in disease progression.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 18 Participant burden (retention rates).
Figures and Tables -
Analysis 12.18

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 18 Participant burden (retention rates).

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 19 Change in mood and well‐being (CAREGIVER).
Figures and Tables -
Analysis 12.19

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 19 Change in mood and well‐being (CAREGIVER).

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 20 Change in burden of care (CAREGIVER).
Figures and Tables -
Analysis 12.20

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 20 Change in burden of care (CAREGIVER).

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 21 Change in quality of life (CAREGIVER).
Figures and Tables -
Analysis 12.21

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 21 Change in quality of life (CAREGIVER).

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 22 Change in speed of information processing.
Figures and Tables -
Analysis 12.22

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 22 Change in speed of information processing.

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Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 23 Change in general health and quality of life.
Figures and Tables -
Analysis 12.23

Comparison 12 Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented), Outcome 23 Change in general health and quality of life.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 1 Change in a global measure of cognition.
Figures and Tables -
Analysis 13.1

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 1 Change in a global measure of cognition.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 2 Change in a global measure of cognition (zero correlation).
Figures and Tables -
Analysis 13.2

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 2 Change in a global measure of cognition (zero correlation).

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 3 Change in a global measure of cognition (composite).
Figures and Tables -
Analysis 13.3

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 3 Change in a global measure of cognition (composite).

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.
Figures and Tables -
Analysis 13.4

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 4 Change in a global measure of cognition (composite)_zero correlation.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 5 Change in disease progression (zero correlation).
Figures and Tables -
Analysis 13.5

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 5 Change in disease progression (zero correlation).

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 6 Change in disease progression.
Figures and Tables -
Analysis 13.6

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 6 Change in disease progression.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 7 Change in immediate memory.
Figures and Tables -
Analysis 13.7

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 7 Change in immediate memory.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 8 Change in delayed memory.
Figures and Tables -
Analysis 13.8

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 8 Change in delayed memory.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 9 Change in language (naming).
Figures and Tables -
Analysis 13.9

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 9 Change in language (naming).

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 10 Change in verbal letter fluency.
Figures and Tables -
Analysis 13.10

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 10 Change in verbal letter fluency.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 11 Change in verbal category fluency.
Figures and Tables -
Analysis 13.11

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 11 Change in verbal category fluency.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 12 Change in attention and working memory.
Figures and Tables -
Analysis 13.12

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 12 Change in attention and working memory.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 13 Change in speed of information processing.
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Analysis 13.13

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 13 Change in speed of information processing.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 14 Change in meta cognition (self‐reported).
Figures and Tables -
Analysis 13.14

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 14 Change in meta cognition (self‐reported).

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 15 Change in meta cognition (informant‐reported).
Figures and Tables -
Analysis 13.15

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 15 Change in meta cognition (informant‐reported).

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 16 Change in capacity for activities of daily living.
Figures and Tables -
Analysis 13.16

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 16 Change in capacity for activities of daily living.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 17 Change in behavioural and psychological symptoms of dementia (BPSD).
Figures and Tables -
Analysis 13.17

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 17 Change in behavioural and psychological symptoms of dementia (BPSD).

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 18 Change in general health and quality of life.
Figures and Tables -
Analysis 13.18

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 18 Change in general health and quality of life.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 19 Change in participants' mood.
Figures and Tables -
Analysis 13.19

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 19 Change in participants' mood.

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Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 23 Change in executive function.
Figures and Tables -
Analysis 13.23

Comparison 13 Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period, Outcome 23 Change in executive function.

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Summary of findings for the main comparison. Cognitive training compared to control immediately post intervention for people with mild to moderate dementia

Cognitive training compared to control immediately post intervention for people with mild to moderate dementia

Patient or population: people with mild to moderate dementia
Setting: Community dwelling or in residential care
Intervention: cognitive training
Comparison: control immediately post intervention

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No. of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with control immediately post intervention

Risk with cognitive training

Change in a global measure of cognition (composite)

Mean change in a global measure of cognition (composite) was 0

SMD 0.42 higher
(0.23 higher to 0.62 higher)

‐

1389
(27 RCTs)

⊕⊕⊕⊝
MODERATEa

Cognitive training probably has a modest effect on global cognition (based on a composite score)

Change in a global measure of cognition

Mean change in a global measure of cognition was 0

SMD 0.65 higher
(0.26 higher to 1.05 higher)

‐

1288
(20 RCTs)

⊕⊕⊝⊝
LOWb

Cognitive training may have a moderate effect on performance in global cognition (based on a screening measure).

Change in delayed memory

Mean change in delayed memory was 0

SMD 0.81 higher
(0.29 higher to 1.32 higher)

‐

543
(11 RCTs)

⊕⊝⊝⊝
VERY LOWb,c

We are unable to determine whether there is any effect on delayed memory due to the very low quality of evidence

Change in participants' mood

Mean change in participants' mood was 0

SMD 0.72 higher
(0.1 lower to 1.54 higher)

‐

577
(8 RCTs)

⊕⊝⊝⊝
VERY LOWb,d

We are unable to determine whether there is any effect on participants' mood due to the very low quality of evidence

Change in capacity for activities of daily living

Mean change in capacity for activities of daily living was 0 SD

SMD 0.12 SD higher
(0.11 lower to 0.35 higher)

‐

687
(10 RCTs)

⊕⊕⊝⊝
LOWd

Cognitive training may not have an effect on capacity for activities of daily living

Participant burden (retention rates)

Study population

OR 0.73
(0.37 to 1.43)

1282
(17 RCTs)

⊕⊕⊝⊝
LOWe

Cognitive training may not be associated with an increase in participant burden as reflected in retention rates

908 per 1000

878 per 1000
(784 to 934)

Change in mood and well‐being (caregiver)

Mean change in mood and well‐being (caregiver) was 0

SMD 0.98 higher
(0.27 higher to 1.68 higher)

‐

36
(1 RCT)

⊕⊕⊕⊝
MODERATEf,g

Cognitive training probably has a large effect on mood and well‐being in the caregiver

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; OR: odds ratio; RCT: randomised controlled trial; SMD: standardised mean difference.

GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

aInconsistency: downgraded 1 point for serious concerns regarding heterogeneity in effect size, which is moderate and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

bInconsistency: downgraded 2 points for very serious concerns regarding heterogeneity in effect size, which is relatively large and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

cPublication bias: downgraded 1 point for strongly suspected publication bias based on visual inspection of the funnel plot, raising the possibility that small negative studies may remain unpublished.

dImprecision: downgraded 1 point for serious concerns related to imprecision because the confidence interval crosses the no treatment threshold.

eImprecision: downgraded 2 points for very serious concerns related to imprecision because the confidence interval includes positive effect, negligible effect, and effect in the direction of the control group.

fRisk of bias: outcome estimation is based on a single study with several limitations related to unclear or high risk of bias in several domains.

gImprecision: downgraded 1 point for serious concerns related to imprecision because the analysis is based on fewer than 400 participants; however the confidence interval does not cross the no effect threshold.

Figures and Tables -
Summary of findings for the main comparison. Cognitive training compared to control immediately post intervention for people with mild to moderate dementia
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Summary of findings 2. Cognitive training compared to control in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

Cognitive training compared to control in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

Patient or population: people with mild to moderate dementia
Setting: Community dwelling or in residential care
Intervention: cognitive training
Comparison: control in the medium term (3 to 12 months post intervention)

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No. of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with control in the medium term (3 to 12 months post intervention)

Risk with cognitive training

Change in a global measure of cognition (composite)

Mean change in a global measure of cognition (composite) was set at 0 SDs

SMD 0.65 higher
(0.11 higher to 1.2 higher)

‐

387
(8 RCTs)

⊕⊝⊝⊝
VERY LOWa,b,c

We are unable to determine whether there is any effect on global cognition (composite) due to the very low quality of evidence

Change on global cognition (screening) (Global cog)

Mean change in global cognition (screening) was set at 0 SDs

SMD 1.33 higher
(0.31 higher to 2.34 higher)

‐

387
(6 RCTs)

⊕⊝⊝⊝
VERY LOWa,d,e

We are unable to determine whether there is any effect on performance in global cognition due to the very low quality of evidence

Change in disease progression

Mean change in disease progression was set at 0 SDs

SMD 0.55 higher
(0.12 higher to 0.98 higher)

‐

98
(3 RCTs)

⊕⊝⊝⊝
VERY LOWa,c

We are unable to determine whether CT slows down disease progression due to the very low quality of evidence

Change in delayed memory

Mean change in delayed memory was set at 0 SDs

SMD 0.97 SD higher
(0.02 higher to 1.92 higher)

‐

253
(4 RCTs)

⊕⊝⊝⊝
VERY LOWa,c,d

We are unable to determine whether there is any effect on performance in delayed memory due to the very low quality of evidence

Change in capacity for activities of daily living

Mean change in capacity for activities of daily living was set at 0 SDs

SMD 0.22 higher
(0.5 lower to 0.94 higher)

‐

64
(3 RCTs)

⊕⊕⊝⊝
LOWc

Cognitive training may not have an effect on capacity for activities of daily living

Change in participants' mood

Mean change in participants' mood was set at 0 SDs

SMD 0.21 higher
(0.54 lower to 0.96 higher)

‐

30
(2 RCTs)

⊕⊕⊝⊝
LOWc

Cognitive training may not have an effect on participants' mood

Change in mood and well‐being (caregiver)

‐

See comment

‐

(0 studies)

‐

No studies have evaluated this outcome in the intermediate term

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; CT: cognitive training; OR: odds ratio; RCT: randomised controlled trial; SD: standard deviation; SMD: standardised mean difference.

GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

aRisk of bias: downgraded 2 points for very serious concerns related to risk of bias: removal of high‐risk studies leads to reasonably large changes in the effect estimate.

bInconsistency: downgraded 1 point for serious concerns regarding heterogeneity in effect size, which is large and statistically significant. However, heterogeneity seems to be partially explained by investigated effect moderators.

cImprecision: downgraded 2 points for very serious concerns related to imprecision because the analysis is based on fewer than 400 participants, and the confidence interval crosses the no effect threshold.

dInconsistency: downgraded 2 points for very serious concerns regarding heterogeneity in effect size, which is relatively large and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

eImprecision: downgraded 1 point for serious concerns related to imprecision because the analysis is based on fewer than 400 participants; however the confidence interval does not cross the no effect threshold.

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Summary of findings 2. Cognitive training compared to control in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia
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Summary of findings 3. Cognitive training compared to alternative treatment immediately post intervention for people with mild to moderate dementia

Cognitive training compared to alternative treatment immediately post intervention for people with mild to moderate dementia

Patient or population: people with mild to moderate dementia
Setting: Community dwelling or in residential care
Intervention: cognitive training
Comparison: alternative treatment immediately post intervention

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No. of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with alternative treatment immediately post intervention

Risk with cognitive training

Change in a global measure of cognition (composite)

Mean change in a global measure of cognition (composite) was 0 SD

SMD 0.21 SD higher
(0.23 lower to 0.64 higher)

‐

769
(7 RCTs)

⊕⊕⊝⊝
LOWa

Cognitive training may not have an effect on global cognition

Change in a global measure of cognition

Mean change in a global measure of cognition was 0

SMD 0.16 higher
(0.28 lower to 0.6 higher)

‐

724
(7 RCTs)

⊕⊝⊝⊝
VERY LOWa,b

We are unable to determine whether there is any effect on global cognition (as measured by a screening tool) due to very low quality of evidence

Change in delayed memory

Mean change in delayed memory was 0

SMD 0.71 higher
(0.33 lower to 1.75 higher)

‐

147
(3 RCTs)

⊕⊝⊝⊝
VERY LOWc,d

We are unable to determine whether there is any effect on performance in delayed memory due to very low quality of the evidence

Change in participants' mood

Mean change in participants' mood was 0

SMD 0.11 lower
(0.29 lower to 0.07 higher)

‐

543
(3 RCTs)

⊕⊕⊕⊝
MODERATEe

Cognitive training probably has no effect on participants' mood

Change in capacity for activities of daily living

Mean change in capacity for activities of daily living was 0

SMD 0.25 lower
(0.43 lower to 0.07 lower)

‐

525
(3 RCTs)

⊕⊕⊕⊝
MODERATEe

Cognitive training probably has no effect on capacity for activities of daily living

Participant burden (retention rates)

Study population

OR 0.78
(0.24 to 2.57)

639
(4 RCTs)

⊕⊝⊝⊝
VERY LOWa,b

We are unable to determine whether cognitive training increases participant burden (as measured by retention rates)

773 per 1000

727 per 1000
(450 to 898)

Change in mood and well‐being (caregiver)

Mean change in mood and well‐being (caregiver) was 0

SMD 1.5 higher
(0.96 higher to 2.04 higher)

‐

88
(1 RCT)

⊕⊕⊕⊝
MODERATEf

Cognitive training probably has a large effect on mood and well‐being in the caregiver

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; OR: odds ratio; RCT: randomised controlled trial; SD: standard deviation; SMD: standardised mean difference.

GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

aImprecision: downgraded 2 points for very serious concerns related to imprecision because the confidence interval includes positive effect, negligible effect, and effect in the direction of the control group.

bInconsistency: downgraded 1 point for serious concerns regarding heterogeneity in effect size, which is moderate and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

cInconsistency: downgraded 2 points for very serious concerns regarding heterogeneity in effect size, which is relatively large and statistically significant. Heterogeneity does not seem to be well explained by investigated effect moderators.

dImprecision: downgraded 2 points for very serious concerns related to imprecision because the analysis is based on fewer than 400 participants, and the confidence interval crosses the no effect threshold.

eImprecision: downgraded 1 point for serious concerns related to imprecision because the sample size includes fewer than 400 participants.

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Summary of findings 3. Cognitive training compared to alternative treatment immediately post intervention for people with mild to moderate dementia
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Summary of findings 4. Cognitive training compared to alternative treatment in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

Cognitive training compared to alternative treatment in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia

Patient or population: people with mild to moderate dementia
Setting: Community dwelling or in residential care
Intervention: cognitive training
Comparison: alternative treatment in the medium term (3 to 12 months post intervention)

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

No. of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with alternative treatment in the medium term (3 to 12 months post intervention)

Risk with cognitive training

Change in a global measure of cognition (composite)

Mean change in a global measure of cognition (composite) was set at 0 SDs

SMD 1.31 SD higher
(1.03 lower to 3.65 higher)

‐

73
(2 RCTs)

⊕⊝⊝⊝
VERY LOW

We are unable to determine whether there is any effect on global cognition (composite) due to very low quality of the evidence

Change in a global measure of cognition

Mean change in a global measure of cognition was set at 0 SDs

SMD 3.2 higher
(2.89 lower to 9.29 higher)

‐

73
(2 RCTs)

⊕⊝⊝⊝
VERY LOW

We are unable to determine whether there is any effect on performance in a screening measure of global cognition due to very low quality of the evidence

Change in disease progression

‐

See comment

‐

(0 studies)

‐

None of the included studies have evaluated this outcome

Change in delayed memory

Mean change in delayed memory was set at 0 SDs

SMD 3.13 higher
(3.57 lower to 9.83 higher)

‐

73
(2 RCTs)

⊕⊝⊝⊝
VERY LOW

We are unable to determine whether there is any effect on performance in delayed memory due to very low quality of the evidence

Change in participants' mood

Mean change in participants' mood was set at 0 SDs

SMD 0.66 lower
(1.35 lower to 0.02 higher)

‐

39
(1 RCT)

⊕⊕⊝⊝
LOWa

Cognitive training may not have an effect on a participants' mood

Change in capacity for activities of daily living

‐

See comment

‐

(0 studies)

‐

None of the included studies have evaluated this outcome

Change in mood and well‐being (caregiver)

‐

See comment

‐

(0 studies)

‐

None of the included studies have evaluated this outcome

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; OR: odds ratio; RCT: randomised controlled trial; SD: standard deviation; SMD: standardised mean difference.

GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

aImprecision: downgraded 2 points for very serious concerns related to imprecision because the confidence interval includes positive effect, negligible effect, and effect in the direction of the control group.

Figures and Tables -
Summary of findings 4. Cognitive training compared to alternative treatment in the medium term (3 to 12 months post intervention) for people with mild to moderate dementia
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Table 1. Summary characteristics of participants in cognitive training and control groups

Study
 

Condition

Sample size (at baseline)

Age, mean (SD),

range

Gender balance (m:f)

Education

Medications (number or proportion on dementia‐related medication)

Baseline MMSE

score

Retention rates

Adverse reactions

Beck 1988

Cognitive training

10

74 (range 68 to 75)

5:5

Attended college = 2

None

Not reported

100%

"many subjects complained of tiring"
 

Control

10

76 (range 70 to 93)

3:7

Attended college = 1

None

Not reported

100%

Not specified

Heiss 1993

Cognitive training

Not reported (18

completed the study)

65.9 (6.28)

9:9

Not reported

None

20.55 (4.42)

Not reported

Not specified

Control (social support)

Not reported (17

completed the study)

66.63 (10.17)

10:7

Not reported

None

20.23 (4.10)

Not reported

Not specified

Control (CT+pyritinol)

17

67.18 (8.51)

Not reported

88.88

Not reported

21.64 (4.55)

Not reported

Not specified

Control (CT+phosphatidylserine)

18

66.74 (6.93)

Not reported

125

Not reported

20.88 (4.73)

Not reported

Not specified

Quayhagen 1995

Cognitive training

25

Not reported

Not reported

Not reported

Not reported

109.8 (12.0) DRS

Not reported

Not specified

Passive control

25

Not reported

Not reported

Not reported

Not reported

109.2 (11.7) DRS

Not reported

Not specified

Active control

28

Not reported

not reported

Not reported

Not reported

110 (12.2) DRS

Not reported

Not specified

de Vreese 1998

Cognitive training

12

NA

NA

NA

NA

NA

NA

NA

Cognitive training+AChE‐I

12

Not reported

Not reported

Not reported

All

17.33 (3.39)

100%

Not specified

Control (placebo drug)

12

Not reported

Not reported

Not reported

All

17.44 (4.67)

100%

Not specified

Control (AChE‐I)

12

Not reported

Not reported

Not reported

All

17 (3.20)

100%

Not specified

Quayhagen 2000

Cognitive training

21

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Passive control

15

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Dyadic counselling control

29

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Seminar groups control

22

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Early‐stage daycare control

16

Not reported

Not reported

Not reported

Not reported

Not assessed

Not reported

Not specified

Davis 2001

Cognitive training

19

68.67 (3.86)

10:9

15.06 (3.86)

5

21.84 (4.03)

100%

Not specified

Control

18

72.56 (7.62)

6:12

12.97 (2.56)

4

22.78 (4.45)

100%

Not specified

Koltai 2001

Cognitive training (group and individual) ‐ shared data

16

72.9 (6.7)

Not reported

15.0 (4.0)

Not reported

22.9 (3.6)

87.5% (missed: 2 participants from group CT)

Not specified

Control

8

73.9 (7.2)

Not reported

15.0 (4.0)

Not reported

26.6 (2.5)

100%

Not specified

Cahn‐Weiner 2003

Cognitive training

19

77. 8 (6.9)

9:8

12.7 (2.1)

All participants: donepezil

24.3 (2.2)

89.4% (missed: 3 participants)

Not specified

Control

20

76.0 (7.7)

5:12

13.1 (3.5)

All participants: donepezil

25.1 (1.7)

85% (missed: 3 participants)

Not specified

Galante 2007

Cognitive training

7

Not reported

Not reported

Not reported

All

22.9 (3.1)

100%

Not specified

Control

5

Not reported

Not reported

Not reported

All

23.1 (1.8)

80% (missed: 1 participant)

Not specified

Neely 2009

Cognitive training

10

74.8 (6.7)

6:4

Not reported

Not reported

22.9 (4.15)

100%

Not specified

Control

10

77.0 (6.6)

6:4

Not reported

Not reported

18.6 (5.7)

90% (missed: 1 participant)

Not specified

Kawashima 2005

Cognitive training

16

85.1 (5.4) (range 76 to 96)

Not reported

Not reported

Not reported

19.9 (7.0)

100%

Not specified

Control

16

86.3 (4.9) (range 78 to 96)

Not reported

Not reported

Not reported

19.6 (5.4)

Not reported

Not specified

Boller 2011

Cognitive training (recollection)

12

81.58

4:8

10.92 (2.94)

Not reported

24 (3.05)

Not reported

Not specified

Cognitive training (recognition)

12

82.67

4:8

12.08 (2.07)

Not reported

24.83 (2.12)

Not reported

Not specified

Control

12

79.33 (3.85)

5:7

11.08 (3.85)

Not reported

25.83 (1.40)

Not reported

Not specified

Fernández‐Calvo 2011

Cognitive training (BBA)

15

75.80 (4.27)

9:6

7.46 (1.84)

All participants on IaCHe

19.33 (2.48)

Not reported

Not specified

Cognitive training (IPP)

15

75.60 (4.55)

8:7

8.40 (2.77)

All participants on IaCHe

20 (2.92)

Not reported

Not specified

Control

15

75.86 (4.15)

8:7

7.26 (3.34)

All participants on IaCHe

20.44 (1.90)

Not reported

Not specified

Goudour 2011

Cognitive training

5

68.8 (10.0)

2:3

9.0 (1.2)

Not reported

20.2 (2.8)

Not reported

Not specified

Control

5

70.0 (5.9)

2:3

9.6 (1.9)

Not reported

20.6 (4.1)

Not reported

Not specified

Jelcic 2012

Cognitive training

20

82.9 (3.6)

2:18

6.7 (2.9)

Not reported

24.4 (2.8)

100%

Not specified

Control

20

81.8 (5.5)

5:15

8.25 (3.6)

Not reported

25 (2.6)

100%

Not specified

Bergamaschi 2013

Cognitive training

16

78.19 (5.50)

Not reported

7.25 (3.24)

All participants: donepezil 5 or 10 mg/d

20.25 (2.95)

Not reported

Not specified

Control

16

77.72 (5.06)

Not reported

5.61 (2.30)

All participants: donepezil 5 or 10 mg/d

21.94 (2.01)

Not reported

Not specified

Lee 2013

Cognitive training (CELP)

6

Not reported

1:6

Nil: 42.8%
< 2 years: 14.3%
3 to 6 years: 28.6%
Secondary: 14.3%
University: 0%

Not reported

15.3 (2.7)

Not reported

Not specified

Cognitive training (TELP)

6

Not reported

3:3

Nil: 16.7%
< 2 years: 16.7%
3 to 6 years: 33.2%
Secondary: 16.7%
University: 16.7%

Not reported

17.6 (4.7)

Not reported

Not specified

Control

7

Reported

2:4

Nil: 33.3%
< 2 years: 16.7%
3 to 6 years: 16.7%
Secondary: 33.3%
University: 0%

Not reported

17 (3.5)

Not reported

Not specified

Mapelli 2013

Cognitive training

10

82.6 (4.85)

Not reported

4.6 (1.5)

Not reported

20.1 (4.2)

100%

Not specified

Control (occupational therapy)

10

84.5 (5.06)

Not reported

4.3 (1.82)

Not reported

19.7 (3.8)

100%

Not specified

Control (no treatment)

10

84.7 (4.42)

Not reported

4 (1.15)

Not reported

18.8 (2.68)

100%

Not specified

Jelcic 2014

Cognitve training (LSS‐tele)

7

86 (5.1)

2:5

6 (3.5)

Not reported

23.7 (2.8)

Not reported

Not specified

Cognitive training (LSS‐direct)

10

82.7 (6)

3:7

6.7 (3.3)

Not reported

24.9 (2.5)

Not reported

Not specified

Control

10

82.3 (5.9)

1:9

8.7 (3.7)

Not reported

24.8 (2.7)

Not reported

Not specified

Quintana Hernandez 2014

Cognitive training

32

Not reported

Not reported

Not reported

100% donepezil

Not reported

84.3%

Not specified

Control muscular relaxation

34

Not reported

Not reported

Not reported

100% donepezil

Not reported

97%

Not specified

Control mindfulness

36

Not reported

Not reported

Not reported

100% donepezil

Not reported

97.2%

Not specified

Control

25

Not reported

Not reported

Not reported

100% donepezil

Not reported

100%

Not specified

Kim 2015

Cognitive training

22

70.4 (7.9)

8:14

8.7 (3.8)

Not reported

23.1 (2.1)

100%

Not specified

Control

21

71.4 (8.2)

7:14

8.5 (3.1)

Not reported

22.8 (1.8)

100%

Not specified

Amieva 2016

Cognitive training

170

78.5 (7.2)

69:99 (data from 168 participants)

No diploma: 10%
Primary school diploma: 34.7%
Secondary school: 29.4%
Baccalaureate and more: 23.5%

89.4% IaCHe, memantine

21.5 (3.2)

72.94% (missed: 46 participants)

Not specified

Usual care

154

78.7 (6.5)

63:90 (data from 154 participants)

No diploma: 15.6%
Primary school diploma: 33.1%
Secondary school: 29.2%
Baccalaureate and more: 20.8%

86.4% IaCHe, memantine

21.6 (3.3)

70.78% (missed: 45 participants)

Not specified

Reminiscence therapy

172

78.8 (6.9)

61:108 (data from 169 participants)

No diploma: 16.3%
Primary school diploma: 33,7%
Secondary school: 30.8%
Baccalaureate and more: 16,9%

90.1% IaCHe, memantine

21.1 (3.1)

68.60% (missed: 54 participants)

Not specified

Individualised cognitive rehabilitation

157

78.9 (6.2)

64:92 (data from 172 participants)

No diploma: 17.2%
Primary school diploma: 35.7%
Secondary school: 26.8%
Baccalaureate and more: 19.1%

86.6% IaCHe, memantine

21.6 (3.0)

77.07% (missed: 36 participants)

Not specified

Cavallo 2016

Cognitive training

40

76.5 (2.88)

13:27

8.53 (3)

36/40

22.65 (1.74)

100%

Not specified

Control

40

76,33 (3,83)

16:24

8.12 (2.79)

38/40

23.05 (2.44)

100%

Not specified

Kao 2016

Cognitive training (spaced retrieval)

48

83.10 (5.0)

33:13

Illiterate: 14 (30, 4)
Primary school: 11 (23, 9)
High school: 14 (30, 4)
College: 7 (15, 2)

Not reported

12.33 (5.41)

95.83% (missed: 2 participants)

Not specified

Cognitive training (spaced retrieval+Montessori activities)

52

82.69 (6.81)

37:12

Illiterate: 9 (18, 4)
Primary school: 13 (26, 5)
High school: 17 (34, 6)
College: 10 (20, 4)

Not reported

12.08 (4.05)

94.23% (missed: 3 participants)

Not specified

Control

48

81.82 (5.89)

Male 29 (64, 4)
Female 16 (35, 6)

Illiterate: 13 (28, 9)
Primary school: 15 (33, 3)
High school: 12 (26, 7)
College: 5 (11, 1)

Not reported

11.84 (5.49)

93.75% (missed: 3 participants)

Not specified

Barban 2016

Cognitive training

42

76.5 (5.7)

13:29

8.8 (3.6)

Not reported

23.4 (1.9)

94.79% (from the 3 groups, not only PWD)

Not specified

Control

39

76.9 (5.7)

11:28

9.2 (3.7)

Not reported

23.4 (1.7)

89.14% (from the 3 groups, not only PWD)

Not specified

Giuli 2016

Cognitive training

51

76.5 (4.3)

40:60

5.9 (4.1)

Not reported

20.2 (3.7)

94.11% (missed: 3 participants)

Not specified

Control

50

78.7 (5.9)

28:72

4.5 (2.3)

Not reported

20.3 (3.5)

94% retention (missed: 3 participants)

Not specified

Venturelli 2016

Cognitive training

20

86 (9)

5:15

Not reported

No anti‐dementia drugs reported

14.0 (1.6)

100%

Not specified

Aerobic exercise

20

84 (7)

4:16

Not reported

No anti‐dementia drugs reported

13.7 (2.3)

100%

Not specified

Aerobic exercise+Cognitive training

20

85 (8)

6:14

Not reported

No anti‐dementia drugs reported

13.8 (1.5)

100%

Not specified

Control

20

84 (10)

17:13

Not reported

No anti‐dementia drugs reported

14.2 (1.5)

100%

Not specified

Tsantali 2017

Cognitive training

17

73.4 (5.7)

Not reported

9.9 (4.2)

All were on inhibitors of cholinesterase, used for at least 2 years

23.2 (1.6)

100%

Not specified

Alternative treatment (cognitive stimulation)

21

74.2 (5.6)

Not reported

9.5 (4.1)

All were on inhibitors of cholinesterase, used for at least 2 years

23.1 (1.4)

100%

Not specified

Control

17

73.3 (4.9)

Not reported

9.8 (4.0)

All were on inhibitors of cholinesterase, used for at least 2 years

22.5 (0.9)

100%

Not specified

Brueggen 2017

Cognitive training

8

(53 to 80)

4:4

(10 to 17)

5 participants on anti‐dementia medication

24 (3.55)

100%

Not specified

Control

10

(59 to 83)

5:3

(11 to 17)

All 8 participants were on anti‐dementia medication

21.75 (3.24)

80% (missed: 2 participants)

Not specified

Serino 2017

VR group ‐ AD

10

86.60
(6.13)

1:9

9.80 (3.97)

Not reported

22.05 (1.62)

100%

Not specified

VR group ‐ normal ageing

8

86.62 (6.19)

4:4

9.12 (5.05)

Not reported

27.73 (2.02)

100%

Not specified

Control

10

88.70 (3.59)

2:8

7.00 (5.00)

Not reported

20.79 (1.80)

100%

Not specified

Giovagnoli 2017

Cognitive training

13

71.69 (7.88)

3:10

6.92 (2.46)

Not reported

23.62 (1.94)

100% (4 dropped out before treatment)

No adverse effects

Alternative treatment (music therapy)

13

73.92 (7.74)

7:6

10.46 (5.3)

Not reported

22.85 (6.28)

100% (4 dropped out before treatment)

No adverse effects

Alternative treatment (neuroeducation)

13

75.31 (5.56)

8:5

7.31 (4.01)

Not reported

21.15 (3.48)

100% (3 dropped out before treatment)

No adverse effects

Trebbastoni 2018

Cognitive training

54

74.26 (6.97)

28:26

8.64 (4.21)

78% AChEIs
27% donezepil 5 mg
24% donezepil 10 mg
20% rivastigmine 9.5 mg
7% rivastigmine 4.6 mg
2% memantine 20 mg

22.20 (2.37)

88.80% (missed: 6 participants)

2 falls (group is not reported) and 2 deaths (1 from each group). Study authors stated that these events were not related to any of the experimental procedures performed

Control

86

76.01 (6.46)

34:52

8.40 (4.12)

88% AChEIs,
40% donepeziil 5 mg
20% rivastigmine 9.5 mg
18% donepezil 10 mg
12% rivastigmine 4.6 mg
2% memantine 20 mg

22.89 (2.72)

100%

2 falls (group is not reported) and 2 deaths (1 from each group). Study authors stated that these events were not related to any of the experimental procedures performed

Kallio 2018

Cognitive training
 

76

82.6 (5.5)
 

34.2% male

32 < 8 years
 

60 (78.9%) taking AD medications; 33 (43.4%) taking anticholinergics
 

21.0 (4.3)
 

68 of 76
 

Not specified
 

 

Control

71

83.6 (5.4)

21.1% male

36 < 8 years
 

62 (87.4%) taking AD medications; 37 (52.1%) taking anticholinergics
 

19.9 (3.9)
 

49 of 71
 

Not specified
 

Date in the table, in some cases, are reported only for those participants who completed the interventions.

AChEI: anti‐cholinesterase inhibitor.

AD: Alzheimer's disease.

BBA: Big Brain Academy.

CELP: computerised errorless learning‐based memory training programme.

CT: cognitive traininng.

IPP: Integrated Psychostimulation Program.

LSS: lexical‐semantic simulation.

TELP: therapist‐led errorless programme.

VR: virtual reality.
Figures and Tables -
Table 1. Summary characteristics of participants in cognitive training and control groups
Navigate to table in Review
Table 2. Summary of duration of interventions and timing of assessments

Study

Duration (weeks)

Session frequency (per week)

Total number of sessions

Session duration (minutes)

Total direct intervention (minutes)

Total direct intervention (hours)

Session format

Adherence rates

Fidelity measures

Beck 1988

6 (cognitive training)

3

18

Approx. 35

Approx. 630

Approx. 10.5

Individual, with a research assistant

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA

Heiss 1993

24 (cognitive training)

2

48

60

2880

48

Individual

Not reported

Not reported

24 (social support)

1

24

60

1440

24

Individual

Not reported

Not reported

24 (cognitive training+pyritinol)

2

48

60

2880

48

Individual

Not reported

Not reported

24 (cognitive training+phosphatidylserine)

2

48

60

2880

48

Individual

Not reported

Not reported

Quayhagen 1995

12 (cognitive training)

6

72

60

4320

72

Individual

Not reported

Caregiver and care recipient were trained together in programme implementation techniques. Return demonstrations by caregivers were required to validate training

NA (passive control)

NA

NA

NA

NA

NA

NA

NA

NA

12 (active control)

Not reported

Not reported

Not reported

Not reported

Not reported

Not reported

Not reported

Caregiver and care recipient were trained together in programme implementation techniques. Return demonstrations by caregivers were required to validate training

de Vreese 1998

NA (cognitive training)

NA

NA

NA

NA

NA

NA

NA

NA

12 (cognitive training+ChE‐I, after 12 weeks on drug)

2

24

45

1080

18

Individual

Not reported

Not reported

12 (placebo drug)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

12 (AChE‐I, after 12 weeks on drug)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

Quayhagen 2000

8 (cognitive training)

1

8

90

720

12

Individual, with help from caregiver

Not reported

Ongoing monitoring of personnel performance to ensure uniformity and consistency of administration of assessments or interventions

8 (dyadic counselling)

1

8

90

720

12

Dyad

Not reported

Ongoing monitoring of personnel performance to ensure uniformity and consistency of administration of assessments or interventions

8 (seminar groups)

1

8

90

720

12

Group

Not reported

Ongoing monitoring of personnel performance to ensure uniformity and consistency of administration of assessments or interventions

8 (daycare)

7

8

240

1920

32

Group

Not reported

Ongoing monitoring of personnel performance to ensure uniformity and consistency of administration of assessments or interventions

NA (wait‐list control)

NA

NA

NA

NA

NA

NA

NA

NA

Davis 2001

5 (cognitive training)

1

5

60

300

5

Individual

Not reported

Not reported

5 (control)

1

5

60

300

5

Individual

Not reported

Not reported

Koltai 2001

5 (cognitive training ‐ group)

1

5

60

300

5

Group

Not reported

Not reported

6 (cognitive training ‐ individual)

1

6

Not reported

Not reported

Not reported

Individual

Not reported

Not reported

NA (wait‐list control)

NA

NA

NA

NA

NA

NA

NA

NA

Cahn‐Weiner 2003

6 (cognitive training)

1

6

Not reported

Not reported

Not reported

Group, with a clinical neuropsychologist

1 participant did not complete the first session, and 2 participants did not complete the fourth session

"All sessions were identical for all participants, with the memory group instructor relying on a trainer's manual with scripts for how to present the information"

6 (control)

1

6

45

270

4.5

Group, with a clinical neuropsychologist

4 participants missed 1 session, and 1 participant missed 2 sessions

Not reported

Galante 2007

4 (cognitive training)

3

12

60

720

12

Individual, with a neuropsychologist

Not reported

Not reported

4 (control)

3

12

60

720

12

Individual, with a neuropsychologist

Not reported

Not reported

Neely 2009

8 (cognitive training ‐ collaborative intervention)

1

8

30 to 40

Approx. 280

Approx. 4.5

Dyads, with a research assistant

Not reported

Not reported

8 (cognitive training ‐ individual intervention)

1

8

30 to 40

Approx. 280

Approx. 4.5

Individual, with a research assistant

Not reported

Not reported

NA (control group)

NA

NA

NA

NA

NA

NA

NA

NA

Kawashima 2005

24 (cognitive training)

2 to 6

48 to 144

Approx. 20

960 to 2880

16 to 48

Individual, with the possibility to ask staff members for advice

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

Boller 2011

2 (cognitive training ‐ recollection)

12

24

60

1440

24

Not reported

Not reported

Not reported

2 (cognitive training ‐ recognition)

12

24

60

1440

24

Not reported

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA

Fernández‐Calvo 2011

12 (cognitive training ‐ BBA)

3

36

60

2160

36

Individual, with an OT and a psychologist

Not reported

Not reported

12 (cognitive training ‐ IPP)

3

36

60

2160

36

Individual, with an OT and a psychologist

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA

Goudour 2011

12 (cognitive training)

1

12

50

600

10

Individual, with a neuropsychologist.

Not reported

Not reported

12 (control)

1

12

50

600

10

Individual, with a clinical psychologist.

Not reported

Not reported

Jelcic 2012

12 (cognitive training)

2

24

60

1440

24

Group, provided by a neuropsychologist

Not reported

Not reported

12 (control)

2

24

60

1440

24

Group, provided by a neuropsychologist

Not reported

Not reported

Bergamaschi 2013

20 (cognitive training)

5

100

120

12000

200

Group, supervised by a neuropsychologist

Not reported

Not reported

20 (control)

Presumed to be 5

Not reported

Not reported

Not reported

Not reported

Group

Not reported

Not reported

Lee 2013

6 (cognitive training ‐ CELP)

2

12

30

360

6

Individual, with a therapist

Not reported

Not reported

6 (cognitive training ‐ TELP)

2

12

30

360

6

Individual, with a therapist

Not reported

Not reported

6 (active control)

2

12

30

360

6

Not reported

Not reported

Not reported

Mapelli 2013

8 (cognitive training)

5

40

60

2400

40

With a therapist

Not reported

Not reported

8 (control ‐ occupational therapy)

5

40

60

2400

40

Not reported

Not reported

Not reported

NA (control ‐ usual care)

NA

NA

NA

NA

NA

NA

NA

NA

Jelcic 2014

12 (cognitive training ‐ LSS‐tele)

2

24

60

1440

24

Small groups, provided by a therapist

Not reported

Not reported

12 (cognitive training ‐ LSS‐direct)

2

24

60

1440

24

Small groups, provided by a therapist

Not reported

Not reported

12 (control)

2

24

60

1440

24

Small groups, provided by a therapist

Not reported

Not reported

Quintana Hernandez 2014

104 (cognitive training)

3 (IPP)

288

90

25920

432

Group, with a clinical psychologist

Not reported

Not reported

104 (muscular relaxation)

3

288

90

25920

432

Group, with a clinical psychologist

Not reported

Not reported

104 (mindfulness)

3

288

90

25920

432

Group, with a clinical psychologist

Not reported

Not reported

NA (passive control)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

Kim 2015

8 (cognitive training)

1

8

60

480

8

Individual and in a group

Not reported

Not reported

8 (control)

1

8

60

480

8

Not reported

Not reported

Not reported

Amieva 2016

96 (cognitive training)

1 (during the first 3 months); 1 every 6 weeks (for the next 21 months)

15

90

1350

22.5

Groups

Not reported

Manual detailing the guidelines of each intervention was provided. Standardised procedures to guarantee homogeneity. Professional visits to therapists to ensure that interventions were applied in accordance with protocol

NA (control ‐ usual care)

NA

NA

NA

NA

NA

NA

NA

NA

96 (reminiscence therapy)

1 (during the first 3 months); 1 every 6 weeks (for the next 21 months)

15

90

1350

22.5

Groups

Not reported

Manual detailing the guidelines of each intervention was provided. Standardised procedures to guarantee homogeneity. Professional visits to therapists to ensure that interventions were applied in accordance with protocol

96 (cognitive rehabilitation)

1 (during the first 3 months); 1 every 6 weeks (for the next 21 months)

15

90

1350

22.5

Individual

Not reported

Manual detailing the guidelines of each intervention was provided. Standardised procedures to guarantee homogeneity. Professional visits to therapists to ensure that interventions were applied in accordance with protocol

Cavallo 2016

12 (cognitive training)

3

36

30

1080

18

Individual, with a neuropsychologist

Not reported

Not reported

12 (control)

3

36

30

1080

18

Individual, with a neuropsychologist

Not reported

Not reported

Kao 2016

6 (cognitive training ‐ spaced retrieval)

5

30

40

1200

20

With a trainer

Not reported

Not reported

6 (cognitive training ‐ spaced retrieval+Montessori activities)

5

30

40

1200

20

With a trainer

Not reported

Not reported

na (control)

NA

NA

NA

NA

NA

NA

NA

NA

Barban 2016

12 (cognitive training)

2

24

60

1440

24

Small groups, provided by a cognitive therapist

Not reported

Not reported

12 (control)

NA

NA

NA

NA

NA

NA

NA

NA

Giuli 2016

10 (cognitive training)

1

10

45

450

7.5

Individually, with homewrok exercises with support of a caregiver

Not reported

Not reported

10 (control)

1

10

45

450

7.5

Not reported

Not reported

Not reported

Venturelli 2016

12 (cognitive training)

5

60

60

3600

60

Performed in collaboration with patients’ caregivers

85±12% in the CT group

Not reported

12 (aerobic exercise)

5

60

60

3600

60

Performed in collaboration with patients’ caregivers

78±8% in the AE group

Not reported

12 (aerobic exercise+cognitive training)

5

60

60

3600

60

Performed in collaboration with patients’ caregivers

75±14% in the AE+CT group

Not reported

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA

Tsantali 2017

16 (cognitive training)

3

48

90

4320

72

Individual with licensed psychologist

Not reported

Not reported

16 (cognitive stimulation)

3

48

90

4320

72

Individual with licensed psychologist

Not reported

Not reported

16 (control)

NA

NA

NA

NA

NA

NA

Not reported

Not reported

Brueggen 2017

12 (cognitive training)

5

60

Approx. 15

Approx. 900

Approx. 15

Individual homework, with 1 meeting per month

100%

Not reported

12 (cognitive rehabilitation)

2

24

60

1440

24

Small group guided by a psychologist and an occupational therapist

100% (including only the 8 participants who completed the study and were, therefore, analysed)

Intervention was based on the CORDIAL programme, via a manual‐guided approach

Giovagnoli 2017

12 (cognitive training)

2

24

45

1080

18

Small groups of 3 participants, guided by a neuropsychologist

Not reported

CT was co‐ordinated by a neuropsychologist using defined materials and procedures

12 (music therapy)

2

24

45

1080

18

Small groups of 3 participants, guided by a music therapist

Not reported

Active music therapy was provided by a music therapist. Sessions were videotaped and evaluated via a structured assessment

12 (neuroeducation)

2

24

45

1080

18

Small groups of 3 participants, co‐ordinated by a neurologist

Not reported

Not reported

Serino 2017

3‐4 (VR group ‐ AD)

3

10

20

200

3.3

Individual with a neuropsychologist

Not reported

Not reported

3‐4 (VR group ‐ normal ageing)

3

10

20

200

3.3

Individual with a neuropsychologist

Not reported

Not reported

NA (control)

NA

NA

NA

NA

NA

Underwent traditional cognitive rehabilitative activities with the neuropsychological staff

NA

NA

Trebbastoni 2018

24 (cognitive training)

2

48

75

3600

60

Group

11% (6 participants) attended less than 80% of sessions of the first period of the study (from T0 to T1).
In the second period, 72.9% attended more than 95% of sessions, 10,4% attended 90% to 95%, 4.2% attended 85% to 89%, and 12.5% attended 80% to 84%

Study authors reported high adherence to a strict protocol

NA

NA

NA

NA

NA

NA

NA

NA

NA

Kallio 2018

12 (cognitive training)

2

24

45

1080

18

Group/individual when required
 

Mean attendance at 22 (92%) sessions
 

CT was administered by trained psychology students under the supervision of an experienced neuropsychologist

 

NA (control)

NA

NA

NA

NA

NA

NA

NA

NA
 

AChEI: anti‐cholinesterase inhibitor.

AD: Alzheimer's disease.

BBA: Big Brain Academy.

CELP: computerised errorless learning‐based memory training programme.

ChEI: cholinesterase inhibitor.

CT: cognitive traininng.

IPP: Integrated Psychostimulation Program.

LSS: lexical‐semantic simulation.

NA: not applicable.

TELP: therapist‐led errorless programme.

VR: virtual reality.
Figures and Tables -
Table 2. Summary of duration of interventions and timing of assessments
Navigate to table in Review
Comparison 1. Cognitive training vs control immediately post intervention

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition (composite) Show forest plot

26

1389

Std. Mean Difference (Random, 95% CI)

0.42 [0.23, 0.61]

2 Change in a global measure of cognition (composite)_zero correlation Show forest plot

26

1389

Std. Mean Difference (Random, 95% CI)

0.24 [0.12, 0.36]

3 Change in a global measure of cognition Show forest plot

20

1288

Std. Mean Difference (IV, Random, 95% CI)

0.65 [0.26, 1.05]

4 Change in a global measure of cognition_zero correlation Show forest plot

20

1287

Std. Mean Difference (IV, Random, 95% CI)

0.27 [0.04, 0.50]

5 Change in disease progression Show forest plot

5

215

Std. Mean Difference (IV, Random, 95% CI)

1.07 [0.59, 1.55]

6 Change in delayed memory Show forest plot

11

543

Std. Mean Difference (IV, Random, 95% CI)

0.81 [0.29, 1.32]

7 Change in immediate memory Show forest plot

17

762

Std. Mean Difference (IV, Random, 95% CI)

0.74 [0.37, 1.12]

8 Change in attention and working memory Show forest plot

12

551

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.08, 1.05]

9 Change in language (naming) Show forest plot

5

311

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.11, 1.12]

10 Change in verbal letter fluency Show forest plot

12

544

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.07, 0.50]

11 Change in verbal category fluency Show forest plot

9

475

Std. Mean Difference (IV, Random, 95% CI)

0.52 [0.23, 0.81]

12 Change in executive function Show forest plot

11

511

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.28, 1.22]

13 Change in speed of information processing Show forest plot

6

201

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.11, 0.54]

14 Change in meta cognition (self‐reported) Show forest plot

2

41

Std. Mean Difference (IV, Random, 95% CI)

0.50 [‐0.15, 1.14]

15 Change in meta cognition (informant‐reported) Show forest plot

2

56

Std. Mean Difference (IV, Random, 95% CI)

‐0.01 [‐1.29, 1.26]

16 Change in participants' mood Show forest plot

8

577

Std. Mean Difference (IV, Random, 95% CI)

0.72 [‐0.10, 1.54]

17 Change in capacity for activities of daily living Show forest plot

10

687

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.11, 0.35]

18 Change in general health and quality of life Show forest plot

5

630

Std. Mean Difference (IV, Random, 95% CI)

‐0.04 [‐0.38, 0.29]

19 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

6

493

Std. Mean Difference (IV, Random, 95% CI)

0.44 [‐0.34, 1.22]

20 Participant burden (retention rates) Show forest plot

17

1282

Odds Ratio (M‐H, Random, 95% CI)

0.73 [0.37, 1.43]

21 Change in burden of care (CAREGIVER) Show forest plot

2

405

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.36, 0.15]

22 Change in quality of life (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.50, 0.83]

23 Change in mood and well‐being (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.98 [0.27, 1.68]
Figures and Tables -
Comparison 1. Cognitive training vs control immediately post intervention
Navigate to table in Review
Comparison 2. Cognitive training vs control in the medium term (3 to 12 months post intervention)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition (composite) Show forest plot

7

387

Std. Mean Difference (Random, 95% CI)

0.65 [0.11, 1.20]

2 Change in a global measure of cognition (composite)_zero correlation Show forest plot

7

387

Std. Mean Difference (Random, 95% CI)

0.40 [0.09, 0.71]

3 Change in a global measure of cognition Show forest plot

6

387

Std. Mean Difference (IV, Random, 95% CI)

1.33 [0.31, 2.34]

4 Change in a global measure of cognition (zero correlation) Show forest plot

6

387

Std. Mean Difference (IV, Random, 95% CI)

0.68 [0.06, 1.30]

5 Change in disease progression Show forest plot

2

98

Std. Mean Difference (IV, Random, 95% CI)

0.55 [0.12, 0.98]

6 Change in disease progression (zero correlation) Show forest plot

2

98

Std. Mean Difference (IV, Random, 95% CI)

0.28 [‐0.14, 0.71]

7 Change in delayed memory Show forest plot

4

274

Std. Mean Difference (IV, Random, 95% CI)

0.97 [0.02, 1.92]

8 Change in immediate memory Show forest plot

7

383

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.00, 1.24]

9 Change in attention and working memory Show forest plot

3

215

Std. Mean Difference (IV, Random, 95% CI)

0.50 [‐0.43, 1.43]

10 Change in language (naming) Show forest plot

4

274

Std. Mean Difference (IV, Random, 95% CI)

0.71 [0.07, 1.34]

11 Change in verbal letter fluency Show forest plot

4

247

Std. Mean Difference (IV, Random, 95% CI)

0.47 [‐0.28, 1.23]

12 Change in verbal category fluency Show forest plot

3

213

Std. Mean Difference (IV, Random, 95% CI)

0.78 [0.38, 1.18]

13 Change in executive function Show forest plot

5

330

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.02, 1.10]

14 Change in speed of information processing Show forest plot

2

45

Std. Mean Difference (IV, Random, 95% CI)

0.30 [‐0.44, 1.04]

15 Change in meta cognition (self‐reported) Show forest plot

1

19

Std. Mean Difference (IV, Random, 95% CI)

0.99 [‐0.01, 1.99]

16 Change in meta cognition (informant‐reported) Show forest plot

1

34

Std. Mean Difference (IV, Random, 95% CI)

‐0.06 [‐0.73, 0.62]

17 Change in participants' mood Show forest plot

2

30

Std. Mean Difference (IV, Random, 95% CI)

0.21 [‐0.54, 0.96]

18 Change in capacity for activities of daily living Show forest plot

3

64

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.50, 0.94]

19 Change in general health and quality of life Show forest plot

1

117

Std. Mean Difference (IV, Random, 95% CI)

‐0.02 [‐0.39, 0.35]

20 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

1

11

Std. Mean Difference (IV, Random, 95% CI)

‐1.34 [‐2.75, 0.07]

21 Change in burden of care (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

22 Change in quality of life (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

23 Change in mood and well‐being (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]
Figures and Tables -
Comparison 2. Cognitive training vs control in the medium term (3 to 12 months post intervention)
Navigate to table in Review
Comparison 3. Cognitive training vs alternative treatment immediately post intervention

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition (composite) Show forest plot

7

769

Std. Mean Difference (Random, 95% CI)

0.21 [‐0.23, 0.64]

2 Change in a global measure of cognition (composite)_zero correlation Show forest plot

7

769

Std. Mean Difference (Random, 95% CI)

‐0.03 [‐0.23, 0.17]

3 Change in a global measure of cognition Show forest plot

7

724

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.28, 0.60]

4 Change in a global measure of cognition_zero correlation Show forest plot

7

724

Std. Mean Difference (IV, Random, 95% CI)

‐0.02 [‐0.24, 0.20]

5 Change in disease progression Show forest plot

3

131

Std. Mean Difference (IV, Random, 95% CI)

0.15 [‐0.33, 0.63]

6 Change in delayed memory Show forest plot

3

147

Std. Mean Difference (IV, Random, 95% CI)

0.71 [‐0.33, 1.75]

7 Change in immediate memory Show forest plot

3

147

Std. Mean Difference (IV, Random, 95% CI)

0.51 [‐0.19, 1.21]

8 Change in attention and working memory Show forest plot

2

69

Std. Mean Difference (IV, Random, 95% CI)

0.91 [‐0.46, 2.27]

9 Change in language (naming) Show forest plot

1

16

Std. Mean Difference (IV, Random, 95% CI)

‐0.63 [‐1.65, 0.38]

10 Change in verbal letter fluency Show forest plot

3

75

Std. Mean Difference (IV, Random, 95% CI)

0.34 [‐0.38, 1.05]

11 Change in verbal category fluency Show forest plot

2

55

Std. Mean Difference (IV, Random, 95% CI)

‐0.28 [‐1.46, 0.89]

12 Change in executive function Show forest plot

4

163

Std. Mean Difference (IV, Random, 95% CI)

1.44 [‐0.26, 3.14]

13 Change in speed of information processing Show forest plot

2

55

Std. Mean Difference (IV, Random, 95% CI)

0.00 [‐0.55, 0.55]

14 Change in meta cognition (self‐reported)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

15 Change in meta cognition (informant‐reported)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

16 Change in participants' mood Show forest plot

3

543

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.29, 0.07]

17 Change in capacity for activities of daily living Show forest plot

3

525

Std. Mean Difference (IV, Random, 95% CI)

‐0.25 [‐0.43, ‐0.07]

18 Change in general health and quality of life Show forest plot

4

631

Std. Mean Difference (IV, Random, 95% CI)

‐0.49 [1.00, 0.02]

19 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

3

672

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.27, 0.06]

20 Participant burden (retention rates) Show forest plot

4

639

Odds Ratio (M‐H, Random, 95% CI)

0.78 [0.24, 2.57]

21 Change in burden of care (CAREGIVER) Show forest plot

3

591

Std. Mean Difference (IV, Random, 95% CI)

‐0.15 [‐0.47, 0.17]

22 Change in quality of life (CAREGIVER) Show forest plot

1

88

Std. Mean Difference (IV, Random, 95% CI)

‐0.25 [‐0.74, 0.24]

23 Change in mood and well‐being (CAREGIVER) Show forest plot

1

88

Std. Mean Difference (IV, Random, 95% CI)

1.50 [0.96, 2.04]
Figures and Tables -
Comparison 3. Cognitive training vs alternative treatment immediately post intervention
Navigate to table in Review
Comparison 4. Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition (composite) Show forest plot

2

73

Std. Mean Difference (Random, 95% CI)

1.31 [‐1.03, 3.65]

2 Change in a global measure of cognition (composite)_zero correlation Show forest plot

2

73

Std. Mean Difference (Random, 95% CI)

0.62 [‐0.52, 1.75]

3 Change in a global measure of cognition Show forest plot

2

73

Std. Mean Difference (IV, Random, 95% CI)

3.20 [‐2.89, 9.29]

4 Change in disease progression (zero correlation)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

5 Change in disease progression

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

6 Change in delayed memory Show forest plot

2

73

Std. Mean Difference (IV, Random, 95% CI)

0.61 [‐1.07, 2.30]

7 Change in immediate memory Show forest plot

2

73

Std. Mean Difference (IV, Random, 95% CI)

0.75 [‐0.61, 2.10]

8 Change in attention and working memory Show forest plot

1

39

Std. Mean Difference (IV, Random, 95% CI)

‐0.05 [‐0.72, 0.61]

9 Change in language (naming) Show forest plot

1

34

Std. Mean Difference (IV, Random, 95% CI)

1.98 [1.14, 2.82]

10 Change in verbal letter fluency Show forest plot

1

39

Std. Mean Difference (IV, Random, 95% CI)

0.29 [‐0.38, 0.96]

11 Change in verbal category fluency Show forest plot

1

39

Std. Mean Difference (IV, Random, 95% CI)

‐0.08 [‐0.74, 0.59]

12 Change in executive function Show forest plot

1

39

Std. Mean Difference (IV, Random, 95% CI)

‐0.30 [‐0.97, 0.37]

13 Change in speed of information processing Show forest plot

1

39

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.77, 0.56]

14 Change in meta cognition (self‐reported)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

15 Change in meta cognition (informant‐reported)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

16 Change in participants' mood Show forest plot

1

39

Std. Mean Difference (IV, Random, 95% CI)

‐0.66 [‐1.35, 0.02]

17 Change in capacity for activities of daily living

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

18 Change in general health and quality of life Show forest plot

1

39

Std. Mean Difference (IV, Random, 95% CI)

0.33 [‐0.34, 1.00]

19 Change in behavioural and psychological symptoms of dementia (BPSD)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

20 Change in burden of care (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

21 Change in quality of life (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

22 Change in mood and well‐being (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]
Figures and Tables -
Comparison 4. Cognitive training vs alternative treatment in the medium term (3 to 12 months post intervention)
Navigate to table in Review
Comparison 5. Cognitive training vs control immediately post intervention ‐ risk of bias

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

20

1288

Std. Mean Difference (IV, Random, 95% CI)

0.65 [0.26, 1.05]

1.1 Lower risk

14

1010

Std. Mean Difference (IV, Random, 95% CI)

0.79 [0.28, 1.30]

1.2 Higher risk

6

278

Std. Mean Difference (IV, Random, 95% CI)

0.30 [‐0.26, 0.87]

2 Change in a global measure of cognition_zero correlation Show forest plot

20

1287

Std. Mean Difference (IV, Random, 95% CI)

0.27 [0.04, 0.50]

2.1 Lower risk

14

1009

Std. Mean Difference (IV, Random, 95% CI)

0.33 [0.03, 0.63]

2.2 Higher risk

6

278

Std. Mean Difference (IV, Random, 95% CI)

0.07 [‐0.20, 0.34]

3 Change in a global measure of cognition (composite) Show forest plot

26

1389

Std. Mean Difference (Random, 95% CI)

0.42 [0.23, 0.61]

3.1 Lower risk

19

1034

Std. Mean Difference (Random, 95% CI)

0.46 [0.19, 0.72]

3.2 Higher risk

7

355

Std. Mean Difference (Random, 95% CI)

0.33 [0.12, 0.55]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

26

1390

Std. Mean Difference (Random, 95% CI)

0.24 [0.12, 0.36]

4.1 Lower risk

19

1035

Std. Mean Difference (Random, 95% CI)

0.23 [0.08, 0.38]

4.2 Higher risk

7

355

Std. Mean Difference (Random, 95% CI)

0.28 [0.07, 0.49]

5 Change in immediate memory Show forest plot

17

762

Std. Mean Difference (IV, Random, 95% CI)

0.74 [0.37, 1.12]

5.1 Lower risk

13

542

Std. Mean Difference (IV, Random, 95% CI)

0.95 [0.46, 1.44]

5.2 Higher risk

5

220

Std. Mean Difference (IV, Random, 95% CI)

0.33 [0.06, 0.60]

6 Change in delayed memory Show forest plot

11

543

Std. Mean Difference (IV, Random, 95% CI)

0.81 [0.29, 1.32]

6.1 Lower risk

8

413

Std. Mean Difference (IV, Random, 95% CI)

0.87 [0.16, 1.59]

6.2 Higher risk

3

130

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.21, 0.92]

7 Change in attention and working memory Show forest plot

12

551

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.08, 1.05]

7.1 Lower risk

9

394

Std. Mean Difference (IV, Random, 95% CI)

0.57 [‐0.03, 1.17]

7.2 Higher risk

3

157

Std. Mean Difference (IV, Random, 95% CI)

0.56 [‐0.57, 1.69]

8 Change in language (naming) Show forest plot

5

311

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.11, 1.12]

9 Change in verbal letter fluency Show forest plot

12

544

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.07, 0.50]

10 Change in speed of information processing Show forest plot

6

201

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.11, 0.54]

11 Change in executive function Show forest plot

11

511

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.28, 1.22]

12 Change in verbal category fluency Show forest plot

9

475

Std. Mean Difference (IV, Random, 95% CI)

0.52 [0.23, 0.81]

12.1 Lower risk

6

318

Std. Mean Difference (IV, Random, 95% CI)

0.49 [0.06, 0.93]

12.2 Higher risk

3

157

Std. Mean Difference (IV, Random, 95% CI)

0.48 [0.16, 0.80]

13 Change in meta cognition (self‐reported) Show forest plot

2

41

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.87, 1.12]

14 Change in meta cognition (informant‐reported) Show forest plot

2

56

Std. Mean Difference (IV, Random, 95% CI)

‐0.65 [‐1.19, ‐0.10]

15 Change in participants' mood Show forest plot

8

576

Std. Mean Difference (IV, Random, 95% CI)

0.72 [‐0.10, 1.54]

16 Change in capacity for activities of daily living Show forest plot

10

705

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.10, 0.34]

16.1 Lower risk

7

516

Std. Mean Difference (IV, Random, 95% CI)

0.09 [‐0.19, 0.37]

16.2 Higher risk

3

189

Std. Mean Difference (IV, Random, 95% CI)

0.18 [‐0.21, 0.58]

17 Change in general health and quality of life Show forest plot

4

542

Std. Mean Difference (IV, Random, 95% CI)

‐0.00 [‐0.42, 0.41]

18 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

6

493

Std. Mean Difference (IV, Random, 95% CI)

0.44 [‐0.34, 1.22]

19 Change in disease progression Show forest plot

5

215

Std. Mean Difference (IV, Random, 95% CI)

1.07 [0.59, 1.55]

20 Change in burden of care (CAREGIVER) Show forest plot

2

405

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.36, 0.15]

21 Change in quality of life (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.50, 0.83]

22 Change in mood and well‐being (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.98 [0.27, 1.68]

23 Participant burden (retention rates) Show forest plot

17

1282

Odds Ratio (M‐H, Random, 95% CI)

0.73 [0.37, 1.43]

24 Change in general health and quality of life Show forest plot

5

630

Std. Mean Difference (IV, Random, 95% CI)

‐0.04 [‐0.38, 0.29]
Figures and Tables -
Comparison 5. Cognitive training vs control immediately post intervention ‐ risk of bias
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Comparison 6. Cognitive training vs control immediately post intervention ‐ intervention dose

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

20

1288

Std. Mean Difference (IV, Random, 95% CI)

0.65 [0.26, 1.05]

1.1 Up to 3 times

15

1112

Std. Mean Difference (IV, Random, 95% CI)

0.51 [0.06, 0.95]

1.2 More than 3 times

5

176

Std. Mean Difference (IV, Random, 95% CI)

1.14 [0.27, 2.01]

2 Change in a global measure of cognition_zero correlation Show forest plot

20

1287

Std. Mean Difference (IV, Random, 95% CI)

0.27 [0.04, 0.50]

2.1 Up to 3 times

15

1111

Std. Mean Difference (IV, Random, 95% CI)

0.23 [‐0.01, 0.47]

2.2 More than 3 times

5

176

Std. Mean Difference (IV, Random, 95% CI)

0.42 [‐0.30, 1.15]

3 Change in a global measure of cognition (composite) Show forest plot

26

1389

Std. Mean Difference (Random, 95% CI)

0.42 [0.23, 0.61]

3.1 Up to 3 times

20

1138

Std. Mean Difference (Random, 95% CI)

0.33 [0.13, 0.53]

3.2 More than 3 times

6

251

Std. Mean Difference (Random, 95% CI)

0.71 [0.27, 1.14]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

26

1338

Std. Mean Difference (Random, 95% CI)

0.24 [0.12, 0.36]

4.1 Up to 3 times

20

1139

Std. Mean Difference (Random, 95% CI)

0.14 [0.02, 0.26]

4.2 More than 3 times

6

199

Std. Mean Difference (Random, 95% CI)

0.54 [0.28, 0.80]

5 Change in immediate memory Show forest plot

17

762

Std. Mean Difference (IV, Random, 95% CI)

0.74 [0.37, 1.12]

5.1 Up to 3 times

14

636

Std. Mean Difference (IV, Random, 95% CI)

0.73 [0.27, 1.19]

5.2 More than 3 times

4

126

Std. Mean Difference (IV, Random, 95% CI)

0.74 [0.29, 1.19]

6 Change in delayed memory Show forest plot

11

543

Std. Mean Difference (IV, Random, 95% CI)

0.81 [0.29, 1.32]

7 Change in attention and working memory Show forest plot

12

551

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.08, 1.05]

8 Change in language (naming) Show forest plot

5

311

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.11, 1.12]

9 Change in verbal letter fluency Show forest plot

12

544

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.07, 0.50]

9.1 Up to 3 times

9

460

Std. Mean Difference (IV, Random, 95% CI)

0.05 [‐0.13, 0.24]

9.2 More than 3 times

3

84

Std. Mean Difference (IV, Random, 95% CI)

1.00 [0.09, 1.92]

10 Change in speed of information processing Show forest plot

6

201

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.11, 0.54]

11 Change in executive function Show forest plot

11

511

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.28, 1.22]

11.1 Up to 3 times

8

380

Std. Mean Difference (IV, Random, 95% CI)

0.57 [0.01, 1.13]

11.2 More than 3 times

3

131

Std. Mean Difference (IV, Random, 95% CI)

1.20 [0.20, 2.20]

12 Change in verbal category fluency Show forest plot

9

475

Std. Mean Difference (IV, Random, 95% CI)

0.52 [0.23, 0.81]

13 Change in meta cognition (self‐reported) Show forest plot

2

41

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.87, 1.12]

14 Change in meta cognition (informant‐reported) Show forest plot

2

56

Std. Mean Difference (IV, Random, 95% CI)

‐0.65 [‐1.19, ‐0.10]

15 Change in participants' mood Show forest plot

8

576

Std. Mean Difference (IV, Random, 95% CI)

0.72 [‐0.10, 1.54]

16 Change in capacity for activities of daily living Show forest plot

10

705

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.10, 0.34]

17 Change in disease progression Show forest plot

5

215

Std. Mean Difference (IV, Random, 95% CI)

1.07 [0.59, 1.55]

18 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

6

493

Std. Mean Difference (IV, Random, 95% CI)

0.44 [‐0.34, 1.22]

19 Change in attention and working memory Show forest plot

12

551

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.08, 1.05]

20 Change in burden of care (CAREGIVER) Show forest plot

2

405

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.36, 0.15]

21 Change in quality of life (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.50, 0.83]

22 Change in mood and well‐being (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.98 [0.27, 1.68]

23 Participant burden (retention rates) Show forest plot

17

1282

Odds Ratio (M‐H, Random, 95% CI)

0.73 [0.37, 1.43]

23.1 Up to 3 times

14

1047

Odds Ratio (M‐H, Random, 95% CI)

0.98 [0.53, 1.81]

23.2 More than 3 times

3

235

Odds Ratio (M‐H, Random, 95% CI)

0.33 [0.10, 1.09]

24 Change in general health and quality of life Show forest plot

5

630

Std. Mean Difference (IV, Random, 95% CI)

‐0.04 [‐0.38, 0.29]
Figures and Tables -
Comparison 6. Cognitive training vs control immediately post intervention ‐ intervention dose
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Comparison 7. Cognitive training vs control immediately post intervention ‐ intervention duration

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

20

1288

Std. Mean Difference (IV, Random, 95% CI)

0.65 [0.26, 1.05]

1.1 Up to 3 months

14

682

Std. Mean Difference (IV, Random, 95% CI)

0.49 [0.09, 0.89]

1.2 More than 3 months

6

606

Std. Mean Difference (IV, Random, 95% CI)

1.03 [0.04, 2.02]

2 Change in a global measure of cognition_zero correlation Show forest plot

20

1287

Std. Mean Difference (IV, Random, 95% CI)

0.27 [0.04, 0.50]

2.1 Up to 3 months

14

682

Std. Mean Difference (IV, Random, 95% CI)

0.15 [‐0.08, 0.38]

2.2 More than 3 months

6

605

Std. Mean Difference (IV, Random, 95% CI)

0.51 [‐0.04, 1.05]

3 Change in a global measure of cognition (composite) Show forest plot

26

1389

Std. Mean Difference (Random, 95% CI)

0.42 [0.23, 0.61]

3.1 Up to 3 months

20

790

Std. Mean Difference (Random, 95% CI)

0.38 [0.18, 0.58]

3.2 More than 3 months

6

599

Std. Mean Difference (Random, 95% CI)

0.54 [0.07, 1.01]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

26

1390

Std. Mean Difference (Random, 95% CI)

0.24 [0.12, 0.36]

4.1 Up to 3 months

20

790

Std. Mean Difference (Random, 95% CI)

0.28 [0.14, 0.42]

4.2 More than 3 months

6

600

Std. Mean Difference (Random, 95% CI)

0.21 [‐0.03, 0.46]

5 Change in immediate memory Show forest plot

17

762

Std. Mean Difference (IV, Random, 95% CI)

0.74 [0.37, 1.12]

5.1 Up to 3 months

14

565

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.29, 1.21]

5.2 More than 3 months

3

197

Std. Mean Difference (IV, Random, 95% CI)

0.76 [0.26, 1.26]

6 Change in delayed memory Show forest plot

11

543

Std. Mean Difference (IV, Random, 95% CI)

0.81 [0.29, 1.32]

7 Change in attention and working memory Show forest plot

12

551

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.08, 1.05]

8 Change in language (naming) Show forest plot

5

311

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.11, 1.12]

9 Change in verbal letter fluency Show forest plot

12

544

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.07, 0.50]

9.1 Up to 3 months

9

350

Std. Mean Difference (IV, Random, 95% CI)

0.03 [‐0.23, 0.28]

9.2 More than 3 months

3

194

Std. Mean Difference (IV, Random, 95% CI)

0.66 [‐0.05, 1.38]

10 Change in speed of information processing Show forest plot

6

201

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.11, 0.54]

11 Change in executive function Show forest plot

11

511

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.28, 1.22]

12 Change in verbal category fluency Show forest plot

9

475

Std. Mean Difference (IV, Random, 95% CI)

0.52 [0.23, 0.81]

13 Change in meta cognition (self‐reported) Show forest plot

2

41

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.87, 1.12]

14 Change in meta cognition (informant‐reported) Show forest plot

2

56

Std. Mean Difference (IV, Random, 95% CI)

‐0.65 [‐1.19, ‐0.10]

15 Change in participants' mood Show forest plot

8

576

Std. Mean Difference (IV, Random, 95% CI)

0.72 [‐0.10, 1.54]

16 Change in capacity for activities of daily living Show forest plot

10

705

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.10, 0.34]

17 Change in disease progression Show forest plot

5

215

Std. Mean Difference (IV, Random, 95% CI)

1.07 [0.59, 1.55]

18 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

6

493

Std. Mean Difference (IV, Random, 95% CI)

0.44 [‐0.34, 1.22]

18.1 Up to 3 months

3

92

Std. Mean Difference (IV, Random, 95% CI)

0.66 [‐1.70, 3.02]

18.2 More than 3 months

3

401

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.29, 0.53]

19 Participant burden (retention rates) Show forest plot

17

1282

Odds Ratio (M‐H, Random, 95% CI)

0.73 [0.37, 1.43]

19.1 Up to 3 months

14

761

Odds Ratio (M‐H, Random, 95% CI)

0.78 [0.35, 1.73]

19.2 More than 3 months

3

521

Odds Ratio (M‐H, Random, 95% CI)

0.24 [0.02, 2.57]

20 Change in burden of care (CAREGIVER) Show forest plot

2

405

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.36, 0.15]

21 Change in quality of life (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.50, 0.83]

22 Change in mood and well‐being (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.98 [0.27, 1.68]

23 Change in general health and quality of life Show forest plot

5

630

Std. Mean Difference (IV, Random, 95% CI)

‐0.04 [‐0.38, 0.29]
Figures and Tables -
Comparison 7. Cognitive training vs control immediately post intervention ‐ intervention duration
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Comparison 8. Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

20

1288

Std. Mean Difference (IV, Random, 95% CI)

0.65 [0.26, 1.05]

1.1 Traditional

13

975

Std. Mean Difference (IV, Random, 95% CI)

0.84 [0.30, 1.39]

1.2 Augmented

7

313

Std. Mean Difference (IV, Random, 95% CI)

0.25 [‐0.21, 0.70]

2 Change in a global measure of cognition_zero correlation Show forest plot

20

1287

Std. Mean Difference (IV, Random, 95% CI)

0.27 [0.04, 0.50]

2.1 Traditional

13

974

Std. Mean Difference (IV, Random, 95% CI)

0.41 [0.11, 0.71]

2.2 Augmented

7

313

Std. Mean Difference (IV, Random, 95% CI)

‐0.03 [‐0.33, 0.26]

3 Change in a global measure of cognition (composite) Show forest plot

26

1389

Std. Mean Difference (Random, 95% CI)

0.42 [0.23, 0.61]

3.1 Traditional

17

1026

Std. Mean Difference (Random, 95% CI)

0.43 [0.18, 0.68]

3.2 Augmented

9

363

Std. Mean Difference (Random, 95% CI)

0.37 [0.10, 0.65]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

26

1390

Std. Mean Difference (Random, 95% CI)

0.24 [0.12, 0.36]

4.1 Traditional

17

1027

Std. Mean Difference (Random, 95% CI)

0.30 [0.12, 0.47]

4.2 Augmented

9

363

Std. Mean Difference (Random, 95% CI)

0.18 [‐0.02, 0.39]

5 Change in immediate memory Show forest plot

17

762

Std. Mean Difference (IV, Random, 95% CI)

0.74 [0.37, 1.12]

5.1 Traditional

12

559

Std. Mean Difference (IV, Random, 95% CI)

0.82 [0.33, 1.30]

5.2 Augmented

5

203

Std. Mean Difference (IV, Random, 95% CI)

0.53 [0.04, 1.02]

6 Change in delayed memory Show forest plot

11

543

Std. Mean Difference (IV, Random, 95% CI)

0.81 [0.29, 1.32]

6.1 Traditional

7

383

Std. Mean Difference (IV, Random, 95% CI)

0.86 [0.15, 1.58]

6.2 Augmented

4

160

Std. Mean Difference (IV, Random, 95% CI)

0.68 [‐0.11, 1.46]

7 Change in attention and working memory Show forest plot

12

551

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.08, 1.05]

7.1 Traditional

8

379

Std. Mean Difference (IV, Random, 95% CI)

0.56 [‐0.17, 1.30]

7.2 Augmented

4

172

Std. Mean Difference (IV, Random, 95% CI)

0.51 [0.07, 0.95]

8 Change in language (naming) Show forest plot

5

311

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.11, 1.12]

9 Change in verbal letter fluency Show forest plot

12

544

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.07, 0.50]

9.1 Traditional

8

386

Std. Mean Difference (IV, Random, 95% CI)

0.26 [‐0.09, 0.62]

9.2 Augmented

4

158

Std. Mean Difference (IV, Random, 95% CI)

0.14 [‐0.42, 0.70]

10 Change in speed of information processing Show forest plot

6

201

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.11, 0.54]

11 Change in executive function Show forest plot

11

511

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.28, 1.22]

11.1 Traditional

8

442

Std. Mean Difference (IV, Random, 95% CI)

0.64 [0.14, 1.14]

11.2 Augmented

3

69

Std. Mean Difference (IV, Random, 95% CI)

1.32 [‐0.26, 2.91]

12 Change in verbal category fluency Show forest plot

9

475

Std. Mean Difference (IV, Random, 95% CI)

0.52 [0.23, 0.81]

12.1 Traditional

6

323

Std. Mean Difference (IV, Random, 95% CI)

0.64 [0.26, 1.01]

12.2 Augmented

3

152

Std. Mean Difference (IV, Random, 95% CI)

0.33 [0.00, 0.65]

13 Change in meta cognition (self‐reported) Show forest plot

2

41

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.87, 1.12]

14 Change in meta cognition (informant‐reported) Show forest plot

2

56

Std. Mean Difference (IV, Random, 95% CI)

‐0.65 [‐1.19, ‐0.10]

15 Change in participants' mood Show forest plot

8

576

Std. Mean Difference (IV, Random, 95% CI)

0.72 [‐0.10, 1.54]

15.1 Traditional

5

423

Std. Mean Difference (IV, Random, 95% CI)

0.90 [‐0.30, 2.10]

15.2 Augmented

3

153

Std. Mean Difference (IV, Random, 95% CI)

0.46 [‐0.94, 1.86]

16 Change in capacity for activities of daily living Show forest plot

10

705

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.10, 0.34]

17 Change in disease progression Show forest plot

5

215

Std. Mean Difference (IV, Random, 95% CI)

1.07 [0.59, 1.55]

18 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

6

493

Std. Mean Difference (IV, Random, 95% CI)

0.44 [‐0.34, 1.22]

19 Participant burden (retention rates) Show forest plot

17

1282

Odds Ratio (M‐H, Random, 95% CI)

0.73 [0.37, 1.43]

19.1 Traditional

10

1017

Odds Ratio (M‐H, Random, 95% CI)

0.59 [0.23, 1.53]

19.2 Augmented

7

265

Odds Ratio (M‐H, Random, 95% CI)

1.02 [0.27, 3.87]

20 Change in burden of care (CAREGIVER) Show forest plot

2

405

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.36, 0.15]

21 Change in quality of life (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.50, 0.83]

22 Change in mood and well‐being (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.98 [0.27, 1.68]

23 Change in general health and quality of life Show forest plot

5

630

Std. Mean Difference (IV, Random, 95% CI)

‐0.04 [‐0.38, 0.29]
Figures and Tables -
Comparison 8. Cognitive training vs control immediately post intervention ‐ type of CT (traditional vs augmented)
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Comparison 9. Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

20

1288

Std. Mean Difference (IV, Random, 95% CI)

0.65 [0.26, 1.05]

1.1 Multidomain

16

1165

Std. Mean Difference (IV, Random, 95% CI)

0.63 [0.19, 1.07]

1.2 Single domain

4

123

Std. Mean Difference (IV, Random, 95% CI)

0.75 [‐0.14, 1.63]

2 Change in a global measure of cognition_zero correlation Show forest plot

20

1287

Std. Mean Difference (IV, Random, 95% CI)

0.27 [0.04, 0.50]

2.1 Multidomain

16

1164

Std. Mean Difference (IV, Random, 95% CI)

0.25 [‐0.01, 0.52]

2.2 Single domain

4

123

Std. Mean Difference (IV, Random, 95% CI)

0.37 [‐0.04, 0.79]

3 Change in a global measure of cognition (composite) Show forest plot

26

1389

Std. Mean Difference (Random, 95% CI)

0.42 [0.23, 0.61]

3.1 Multidomain

16

990

Std. Mean Difference (Random, 95% CI)

0.44 [0.18, 0.71]

3.2 Single domain

10

399

Std. Mean Difference (Random, 95% CI)

0.35 [0.10, 0.59]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

26

1390

Std. Mean Difference (Random, 95% CI)

0.24 [0.12, 0.36]

4.1 Multidomain

16

991

Std. Mean Difference (Random, 95% CI)

0.27 [0.10, 0.44]

4.2 Single domain

10

399

Std. Mean Difference (Random, 95% CI)

0.23 [0.04, 0.43]

5 Change in immediate memory Show forest plot

17

762

Std. Mean Difference (IV, Random, 95% CI)

0.74 [0.37, 1.12]

5.1 Multidomain

10

540

Std. Mean Difference (IV, Random, 95% CI)

0.80 [0.24, 1.35]

5.2 Single domain

7

222

Std. Mean Difference (IV, Random, 95% CI)

0.58 [0.22, 0.94]

6 Change in delayed memory Show forest plot

11

543

Std. Mean Difference (IV, Random, 95% CI)

0.81 [0.29, 1.32]

6.1 Multidomain

6

369

Std. Mean Difference (IV, Random, 95% CI)

1.15 [0.32, 1.97]

6.2 Single domain

5

174

Std. Mean Difference (IV, Random, 95% CI)

0.41 [‐0.11, 0.94]

7 Change in attention and working memory Show forest plot

12

551

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.08, 1.05]

7.1 Multidomain

8

411

Std. Mean Difference (IV, Random, 95% CI)

0.50 [‐0.14, 1.15]

7.2 Single domain

4

140

Std. Mean Difference (IV, Random, 95% CI)

0.68 [‐0.14, 1.49]

8 Change in language (naming) Show forest plot

5

311

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.11, 1.12]

9 Change in verbal letter fluency Show forest plot

12

544

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.07, 0.50]

9.1 Multidomain

8

406

Std. Mean Difference (IV, Random, 95% CI)

0.37 [‐0.04, 0.78]

9.2 Single domain

4

138

Std. Mean Difference (IV, Random, 95% CI)

‐0.04 [‐0.37, 0.30]

10 Change in speed of information processing Show forest plot

6

201

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.11, 0.54]

11 Change in executive function Show forest plot

11

511

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.28, 1.22]

11.1 Multidomain

8

408

Std. Mean Difference (IV, Random, 95% CI)

0.99 [0.44, 1.55]

11.2 Single domain

3

103

Std. Mean Difference (IV, Random, 95% CI)

0.08 [‐0.53, 0.68]

12 Change in verbal category fluency Show forest plot

9

475

Std. Mean Difference (IV, Random, 95% CI)

0.52 [0.23, 0.81]

12.1 Multidomain

6

371

Std. Mean Difference (IV, Random, 95% CI)

0.70 [0.38, 1.02]

12.2 Single domain

3

104

Std. Mean Difference (IV, Random, 95% CI)

0.14 [‐0.25, 0.52]

13 Change in meta cognition (self‐reported) Show forest plot

2

41

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.87, 1.12]

14 Change in meta cognition (informant‐reported) Show forest plot

2

56

Std. Mean Difference (IV, Random, 95% CI)

‐0.65 [‐1.19, ‐0.10]

15 Change in participants' mood Show forest plot

8

576

Std. Mean Difference (IV, Random, 95% CI)

0.72 [‐0.10, 1.54]

16 Change in capacity for activities of daily living Show forest plot

10

705

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.10, 0.34]

17 Change in disease progression Show forest plot

5

215

Std. Mean Difference (IV, Random, 95% CI)

1.07 [0.59, 1.55]

18 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

6

493

Std. Mean Difference (IV, Random, 95% CI)

0.44 [‐0.34, 1.22]

19 Participant burden (retention rates) Show forest plot

17

1282

Odds Ratio (M‐H, Random, 95% CI)

0.73 [0.37, 1.43]

19.1 Multidomain

12

988

Odds Ratio (M‐H, Random, 95% CI)

0.61 [0.21, 1.81]

19.2 Single domain

5

294

Odds Ratio (M‐H, Random, 95% CI)

0.66 [0.24, 1.77]

20 Change in burden of care (CAREGIVER) Show forest plot

2

405

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.36, 0.15]

21 Change in quality of life (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.50, 0.83]

22 Change in mood and well‐being (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.98 [0.27, 1.68]

23 Change in general health and quality of life Show forest plot

5

630

Std. Mean Difference (IV, Random, 95% CI)

‐0.04 [‐0.38, 0.29]
Figures and Tables -
Comparison 9. Cognitive training vs control immediately post intervention ‐ type of CT (multi‐domain vs single domain)
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Comparison 10. Cognitive training vs control immediately post intervention ‐ type of control (passive vs active)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

20

1288

Std. Mean Difference (IV, Random, 95% CI)

0.65 [0.26, 1.05]

1.1 Passive

11

912

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.22, 1.28]

1.2 Active

9

376

Std. Mean Difference (IV, Random, 95% CI)

0.54 [‐0.11, 1.19]

2 Change in a global measure of cognition_zero correlation Show forest plot

20

1287

Std. Mean Difference (IV, Random, 95% CI)

0.27 [0.04, 0.50]

2.1 Passive

11

911

Std. Mean Difference (IV, Random, 95% CI)

0.27 [‐0.04, 0.58]

2.2 Active

9

376

Std. Mean Difference (IV, Random, 95% CI)

0.27 [‐0.10, 0.65]

3 Change in a global measure of cognition (composite) Show forest plot

26

1389

Std. Mean Difference (Random, 95% CI)

0.42 [0.23, 0.61]

3.1 Passive

14

875

Std. Mean Difference (Random, 95% CI)

0.31 [0.06, 0.55]

3.2 Active

13

514

Std. Mean Difference (Random, 95% CI)

0.53 [0.26, 0.81]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

26

1390

Std. Mean Difference (Random, 95% CI)

0.24 [0.12, 0.36]

4.1 Passive

14

876

Std. Mean Difference (Random, 95% CI)

0.24 [0.04, 0.43]

4.2 Active

13

514

Std. Mean Difference (Random, 95% CI)

0.30 [0.13, 0.48]

5 Change in immediate memory Show forest plot

17

762

Std. Mean Difference (IV, Random, 95% CI)

0.74 [0.37, 1.12]

5.1 Passive

7

311

Std. Mean Difference (IV, Random, 95% CI)

0.64 [0.20, 1.08]

5.2 Active

11

451

Std. Mean Difference (IV, Random, 95% CI)

0.82 [0.25, 1.39]

6 Change in delayed memory Show forest plot

11

543

Std. Mean Difference (IV, Random, 95% CI)

0.81 [0.29, 1.32]

6.1 Passive

6

325

Std. Mean Difference (IV, Random, 95% CI)

0.52 [0.11, 0.94]

6.2 Active

5

218

Std. Mean Difference (IV, Random, 95% CI)

1.04 [‐0.04, 2.12]

7 Change in attention and working memory Show forest plot

12

551

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.08, 1.05]

7.1 Passive

4

206

Std. Mean Difference (IV, Random, 95% CI)

0.37 [‐0.25, 0.99]

7.2 Active

8

345

Std. Mean Difference (IV, Random, 95% CI)

0.63 [‐0.03, 1.29]

8 Change in language (naming) Show forest plot

5

311

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.11, 1.12]

9 Change in verbal letter fluency Show forest plot

12

544

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.07, 0.50]

9.1 Passive

4

263

Std. Mean Difference (IV, Random, 95% CI)

0.35 [‐0.03, 0.72]

9.2 Active

8

281

Std. Mean Difference (IV, Random, 95% CI)

0.14 [‐0.27, 0.55]

10 Change in speed of information processing Show forest plot

6

201

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.11, 0.54]

11 Change in executive function Show forest plot

11

511

Std. Mean Difference (IV, Random, 95% CI)

0.75 [0.28, 1.22]

11.1 Passive

6

285

Std. Mean Difference (IV, Random, 95% CI)

1.37 [0.60, 2.14]

11.2 Active

6

226

Std. Mean Difference (IV, Random, 95% CI)

0.21 [‐0.11, 0.53]

12 Change in verbal category fluency Show forest plot

9

475

Std. Mean Difference (IV, Random, 95% CI)

0.52 [0.23, 0.81]

13 Change in meta cognition (self‐reported) Show forest plot

2

41

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.87, 1.12]

14 Change in meta cognition (informant‐reported) Show forest plot

2

56

Std. Mean Difference (IV, Random, 95% CI)

‐0.65 [‐1.19, ‐0.10]

15 Change in participants' mood Show forest plot

8

576

Std. Mean Difference (IV, Random, 95% CI)

0.72 [‐0.10, 1.54]

15.1 Passive

3

383

Std. Mean Difference (IV, Random, 95% CI)

1.02 [‐1.07, 3.10]

15.2 Active

5

193

Std. Mean Difference (IV, Random, 95% CI)

0.58 [‐0.34, 1.49]

16 Change in capacity for activities of daily living Show forest plot

10

705

Std. Mean Difference (IV, Random, 95% CI)

0.12 [‐0.10, 0.34]

17 Change in disease progression Show forest plot

5

215

Std. Mean Difference (IV, Random, 95% CI)

1.07 [0.59, 1.55]

18 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

6

493

Std. Mean Difference (IV, Random, 95% CI)

0.44 [‐0.34, 1.22]

19 Participant burden (retention rates) Show forest plot

17

1282

Odds Ratio (M‐H, Random, 95% CI)

0.73 [0.37, 1.43]

19.1 Passive

9

910

Odds Ratio (M‐H, Random, 95% CI)

0.49 [0.17, 1.40]

19.2 Active

8

372

Odds Ratio (M‐H, Random, 95% CI)

1.17 [0.38, 3.64]

20 Change in burden of care (CAREGIVER) Show forest plot

2

405

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.36, 0.15]

21 Change in quality of life (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.50, 0.83]

22 Change in mood and well‐being (CAREGIVER) Show forest plot

1

36

Std. Mean Difference (IV, Random, 95% CI)

0.98 [0.27, 1.68]

23 Change in general health and quality of life Show forest plot

5

630

Std. Mean Difference (IV, Random, 95% CI)

‐0.04 [‐0.38, 0.29]
Figures and Tables -
Comparison 10. Cognitive training vs control immediately post intervention ‐ type of control (passive vs active)
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Comparison 11. Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

7

724

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.28, 0.60]

1.1 Up to 3 times

3

551

Std. Mean Difference (IV, Random, 95% CI)

0.32 [‐0.48, 1.12]

1.2 More than 3 times

4

173

Std. Mean Difference (IV, Random, 95% CI)

0.13 [‐0.63, 0.89]

2 Change in a global measure of cognition_zero correlation Show forest plot

7

724

Std. Mean Difference (IV, Random, 95% CI)

‐0.02 [‐0.24, 0.20]

2.1 Up to 3 times

3

551

Std. Mean Difference (IV, Random, 95% CI)

0.02 [‐0.35, 0.40]

2.2 More than 3 times

4

173

Std. Mean Difference (IV, Random, 95% CI)

0.01 [‐0.41, 0.43]

3 Change in a global measure of cognition (composite) Show forest plot

7

769

Std. Mean Difference (Random, 95% CI)

0.21 [‐0.23, 0.64]

3.1 Up to 3 times

4

636

Std. Mean Difference (Random, 95% CI)

0.23 [‐0.27, 0.74]

3.2 More than 3 times

3

133

Std. Mean Difference (Random, 95% CI)

0.32 [‐0.90, 1.55]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

7

769

Std. Mean Difference (Random, 95% CI)

‐0.03 [‐0.23, 0.17]

4.1 Up to 3 times

4

636

Std. Mean Difference (Random, 95% CI)

‐0.04 [‐0.22, 0.14]

4.2 More than 3 times

3

133

Std. Mean Difference (Random, 95% CI)

0.05 [‐0.59, 0.70]

5 Change in immediate memory Show forest plot

3

147

Std. Mean Difference (IV, Random, 95% CI)

0.51 [‐0.19, 1.21]

6 Change in delayed memory Show forest plot

3

147

Std. Mean Difference (IV, Random, 95% CI)

0.71 [‐0.33, 1.75]

7 Change in attention and working memory Show forest plot

2

69

Std. Mean Difference (IV, Random, 95% CI)

0.91 [‐0.46, 2.27]

8 Change in language (naming) Show forest plot

1

16

Std. Mean Difference (IV, Random, 95% CI)

‐0.63 [‐1.65, 0.38]

9 Change in verbal letter fluency Show forest plot

3

75

Std. Mean Difference (IV, Random, 95% CI)

0.34 [‐0.38, 1.05]

10 Change in verbal category fluency Show forest plot

2

55

Std. Mean Difference (IV, Random, 95% CI)

‐0.28 [‐1.46, 0.89]

11 Change in executive function Show forest plot

4

163

Std. Mean Difference (IV, Random, 95% CI)

1.44 [‐0.26, 3.14]

12 Change in meta cognition (self‐reported)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

13 Change in meta cognition (informant‐reported)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

14 Change in participants' mood Show forest plot

3

543

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.29, 0.07]

15 Change in capacity for activities of daily living Show forest plot

3

525

Std. Mean Difference (IV, Random, 95% CI)

‐0.25 [‐0.43, ‐0.07]

16 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

3

672

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.27, 0.06]

17 Change in disease progression Show forest plot

3

131

Std. Mean Difference (IV, Random, 95% CI)

0.15 [‐0.33, 0.63]

18 Participant burden (retention rates) Show forest plot

4

639

Odds Ratio (M‐H, Random, 95% CI)

0.78 [0.24, 2.57]

19 Change in mood and well‐being (CAREGIVER) Show forest plot

1

88

Std. Mean Difference (IV, Random, 95% CI)

1.50 [0.96, 2.04]

20 Change in burden of care (CAREGIVER) Show forest plot

3

591

Std. Mean Difference (IV, Random, 95% CI)

‐0.15 [‐0.47, 0.17]

21 Change in quality of life (CAREGIVER) Show forest plot

1

88

Std. Mean Difference (IV, Random, 95% CI)

‐0.25 [‐0.74, 0.24]

22 Change in speed of information processing Show forest plot

2

55

Std. Mean Difference (IV, Random, 95% CI)

‐0.21 [‐0.77, 0.34]

23 Change in general health and quality of life Show forest plot

4

631

Std. Mean Difference (IV, Random, 95% CI)

‐0.49 [1.00, 0.02]
Figures and Tables -
Comparison 11. Cognitive training vs alternative treatment immediately post intervention ‐ intervention dose
Navigate to table in Review
Comparison 12. Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented)

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

7

724

Std. Mean Difference (IV, Random, 95% CI)

0.16 [‐0.28, 0.60]

1.1 Traditional

4

646

Std. Mean Difference (IV, Random, 95% CI)

‐0.19 [‐0.35, ‐0.02]

1.2 Augmented

3

78

Std. Mean Difference (IV, Random, 95% CI)

1.04 [‐0.29, 2.36]

2 Change in a global measure of cognition_zero correlation Show forest plot

7

724

Std. Mean Difference (IV, Random, 95% CI)

‐0.02 [‐0.24, 0.20]

2.1 Traditional

4

646

Std. Mean Difference (IV, Random, 95% CI)

‐0.12 [‐0.29, 0.04]

2.2 Augmented

3

78

Std. Mean Difference (IV, Random, 95% CI)

0.44 [‐0.18, 1.06]

3 Change in a global measure of cognition (composite) Show forest plot

7

769

Std. Mean Difference (Random, 95% CI)

0.21 [‐0.23, 0.64]

3.1 Traditional

4

643

Std. Mean Difference (Random, 95% CI)

‐0.17 [‐0.34, ‐0.00]

3.2 Augmented

3

126

Std. Mean Difference (Random, 95% CI)

1.09 [0.14, 2.04]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

7

769

Std. Mean Difference (Random, 95% CI)

‐0.03 [‐0.23, 0.17]

4.1 Traditional

4

643

Std. Mean Difference (Random, 95% CI)

‐0.11 [‐0.28, 0.06]

4.2 Augmented

3

126

Std. Mean Difference (Random, 95% CI)

0.43 [‐0.04, 0.90]

5 Change in immediate memory Show forest plot

3

147

Std. Mean Difference (IV, Random, 95% CI)

0.51 [‐0.19, 1.21]

6 Change in delayed memory Show forest plot

3

147

Std. Mean Difference (IV, Random, 95% CI)

0.71 [‐0.33, 1.75]

7 Change in attention and working memory Show forest plot

2

69

Std. Mean Difference (IV, Random, 95% CI)

0.91 [‐0.46, 2.27]

8 Change in language (naming) Show forest plot

1

16

Std. Mean Difference (IV, Random, 95% CI)

‐0.63 [‐1.65, 0.38]

9 Change in verbal letter fluency Show forest plot

3

75

Std. Mean Difference (IV, Random, 95% CI)

0.34 [‐0.38, 1.05]

10 Change in verbal category fluency Show forest plot

2

55

Std. Mean Difference (IV, Random, 95% CI)

‐0.28 [‐1.46, 0.89]

11 Change in executive function Show forest plot

4

163

Std. Mean Difference (IV, Random, 95% CI)

1.44 [‐0.26, 3.14]

12 Change in meta cognition (self‐reported)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

13 Change in meta cognition (informant‐reported)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

14 Change in participants' mood Show forest plot

3

543

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.29, 0.07]

15 Change in capacity for activities of daily living Show forest plot

3

525

Std. Mean Difference (IV, Random, 95% CI)

‐0.25 [‐0.43, ‐0.07]

16 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

3

672

Std. Mean Difference (IV, Random, 95% CI)

‐0.11 [‐0.27, 0.06]

17 Change in disease progression Show forest plot

3

131

Std. Mean Difference (IV, Random, 95% CI)

0.15 [‐0.33, 0.63]

18 Participant burden (retention rates) Show forest plot

4

639

Odds Ratio (M‐H, Random, 95% CI)

0.78 [0.24, 2.57]

19 Change in mood and well‐being (CAREGIVER) Show forest plot

1

88

Std. Mean Difference (IV, Random, 95% CI)

1.50 [0.96, 2.04]

20 Change in burden of care (CAREGIVER) Show forest plot

3

591

Std. Mean Difference (IV, Random, 95% CI)

‐0.15 [‐0.47, 0.17]

21 Change in quality of life (CAREGIVER) Show forest plot

1

88

Std. Mean Difference (IV, Random, 95% CI)

‐0.25 [‐0.74, 0.24]

22 Change in speed of information processing Show forest plot

2

55

Std. Mean Difference (IV, Random, 95% CI)

‐0.21 [‐0.77, 0.34]

23 Change in general health and quality of life Show forest plot

4

631

Std. Mean Difference (IV, Random, 95% CI)

‐0.49 [1.00, 0.02]
Figures and Tables -
Comparison 12. Cognitive training vs alternative treatment immediately post intervention ‐ type of CT (traditional vs augmented)
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Comparison 13. Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Change in a global measure of cognition Show forest plot

6

387

Std. Mean Difference (IV, Random, 95% CI)

1.33 [0.31, 2.34]

2 Change in a global measure of cognition (zero correlation) Show forest plot

6

387

Std. Mean Difference (IV, Random, 95% CI)

0.68 [0.06, 1.30]

3 Change in a global measure of cognition (composite) Show forest plot

7

Std. Mean Difference (Random, 95% CI)

0.65 [0.11, 1.20]

3.1 Up to 3 months

3

Std. Mean Difference (Random, 95% CI)

‐0.05 [‐0.54, 0.43]

3.2 More than 3 months

4

Std. Mean Difference (Random, 95% CI)

1.03 [0.33, 1.72]

4 Change in a global measure of cognition (composite)_zero correlation Show forest plot

7

Std. Mean Difference (Random, 95% CI)

0.40 [0.09, 0.71]

4.1 Up to 3 months

3

Std. Mean Difference (Random, 95% CI)

‐0.06 [‐0.54, 0.42]

4.2 More than 4 months

4

Std. Mean Difference (Random, 95% CI)

0.57 [0.21, 0.93]

5 Change in disease progression (zero correlation) Show forest plot

2

98

Std. Mean Difference (IV, Random, 95% CI)

0.28 [‐0.14, 0.71]

6 Change in disease progression Show forest plot

2

98

Std. Mean Difference (IV, Random, 95% CI)

0.55 [0.12, 0.98]

7 Change in immediate memory Show forest plot

7

383

Std. Mean Difference (IV, Random, 95% CI)

0.62 [0.00, 1.24]

7.1 Up to 3 months

3

64

Std. Mean Difference (IV, Random, 95% CI)

‐0.34 [‐1.12, 0.43]

7.2 More than 3 months

4

319

Std. Mean Difference (IV, Random, 95% CI)

1.14 [0.53, 1.74]

8 Change in delayed memory Show forest plot

4

270

Std. Mean Difference (IV, Random, 95% CI)

0.97 [0.02, 1.92]

9 Change in language (naming) Show forest plot

4

274

Std. Mean Difference (IV, Random, 95% CI)

‐0.87 [‐3.81, 2.08]

10 Change in verbal letter fluency Show forest plot

4

247

Std. Mean Difference (IV, Random, 95% CI)

0.47 [‐0.28, 1.23]

11 Change in verbal category fluency Show forest plot

3

213

Std. Mean Difference (IV, Random, 95% CI)

0.78 [0.38, 1.18]

12 Change in attention and working memory Show forest plot

3

215

Std. Mean Difference (IV, Random, 95% CI)

0.50 [‐0.43, 1.43]

13 Change in speed of information processing Show forest plot

2

45

Std. Mean Difference (IV, Random, 95% CI)

0.30 [‐0.44, 1.04]

14 Change in meta cognition (self‐reported) Show forest plot

1

19

Std. Mean Difference (IV, Random, 95% CI)

0.99 [‐0.01, 1.99]

15 Change in meta cognition (informant‐reported) Show forest plot

1

34

Std. Mean Difference (IV, Random, 95% CI)

‐0.06 [‐0.73, 0.62]

16 Change in capacity for activities of daily living Show forest plot

3

64

Std. Mean Difference (IV, Random, 95% CI)

0.22 [‐0.50, 0.94]

17 Change in behavioural and psychological symptoms of dementia (BPSD) Show forest plot

1

11

Std. Mean Difference (IV, Random, 95% CI)

‐1.34 [‐2.75, 0.07]

18 Change in general health and quality of life Show forest plot

1

117

Std. Mean Difference (IV, Random, 95% CI)

‐0.02 [‐0.39, 0.35]

19 Change in participants' mood Show forest plot

2

30

Std. Mean Difference (IV, Random, 95% CI)

0.21 [‐0.54, 0.96]

20 Change in mood and well‐being (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

21 Change in burden of care (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

22 Change in quality of life (CAREGIVER)

0

0

Std. Mean Difference (IV, Random, 95% CI)

0.0 [0.0, 0.0]

23 Change in executive function Show forest plot

5

330

Std. Mean Difference (IV, Random, 95% CI)

0.56 [0.02, 1.10]
Figures and Tables -
Comparison 13. Cognitive training vs control in the medium term (3 to 12 months post intervention) ‐ follow‐up period
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