Background
Aim
Method
Inclusion criteria
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Articles in English language in academic journals.
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Peer reviewed articles.
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Articles available electronically.
Exclusion criteria
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Reviews, conference papers, short surveys, notes, book chapters, editorials, letters and articles in press.
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Articles not in English language.
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Articles not readily accessible electronically.
Autonomic dysfunction in Rett syndrome
Neuronal vulnerability in Rett syndrome
Autonomic dysfunction
Targeting the clinical phenotype
Emotional and Behavioural dysregulation
The interplay between emotion and behaviour
Emotional and Behavioural dysregulation in RTT
Emotional, Behavioural and Autonomic dysregulation in RTT
EBAD as a target for clinical trials in RTT
Clinical trials in Rett syndrome
Authors | Na | Duration (months) | Design | Intervention | Physiological Measurement(s) of Autonomic Function | Outcome Measures | Comments# | Reference |
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Mancini et al. (2018) | 36 (26) | 6 | Randomised multicentre, placebo controlled double-blind | Desipramine | • ECG • AHI polysomnography • Respiration rate • Oxygen desaturation | Primary: • Change in AHI at 6 months from baseline Secondary: • CSS • SSI • Number of apnoeas • Number of hypopneas • Oxygen desaturation | No significant differences between groups (high dose, low dose or placebo) were observed in the outcome measures (AHI, breathing patterns, CSS or SSI) from baseline to 6 months. | [134] |
Downs et al. (2018) | 12 | 6b | Modified stepped wedge individually randomised controlled trial | Environmental enrichment | N/A | Primary: • Change from baseline in RSGMS Secondary: • Blood levels of BDNF protein • BMI • Sleep quality as measured using the DIMS subscale of the parent rated SDSC. • Mood as measured using the mood subscale of the RSBQ | • After 6 months of treatment, the enriched environment accounted for improvements in gross motor skills and elevated blood BDNF levels. • No change from baseline in BMI, sleep quality or mood. | [133] |
O’Leary et al. (2018) | 30 (29) | 18c | Randomised placebo controlled double-blind crossover | IGF-1 (full length) | Bioradio | Primary: • ADAMS • SA subscale • RSBQ • F/A subscale • PTSVAS top three concerns • CGI • PGI • Kerr (overall severity scale) Secondary: • Additional ADAMS subscales • additional RSBQ subscales • ABC-C subscales • MSEL • Vineland-II • CSBS-DP • Cardiorespiratory biomarkers | No significant improvements were noted between treatment groups | [132] |
Glaze et al. (2017) | 56d | 0.5–1 | Randomised Phase 2, placebo controlled double-blind | Trofinetide (IGF-1 tripeptide analogue) | • EEG • Electromyography • Oxygen desaturation • HRV • Respiratory rate variability | • Modified apnoea index score • ABC-C • MBA • RSSS • CGI-I • VAS | • Efficacy was demonstrated for trofinetide (Day 26 for 70 mg/kg treatment group, n = 17) in comparison to placebo for core features. • Effect sizes (with CI): ➢ CGI-I: − 0.554 (− 1.34, 0.23) ➢ Caregiver Top 3 Concerns: − 0.63 (− 1.42, 0.16) ➢ MBA change index: − 0.607 (− 1.39, 0.18) | [131] |
Smith-Hicks et al. (2017) | 38e | 6 | Randomised open-label | Dextromethorphan | EEG | • Cognitive status: ➢ MSEL ➢ VABS • Behavioural characterisation: ➢ Parent-completed ABC–Community Version ➢ *SSI ➢ RSSS • Gait • EEG | Dose dependent improvements deemed to be of statistical significance were noted for clinical seizures, receptive language and behavioural hyperactivity; however, there was no statistically significant improvement in global severity as assessed by the RSSS. | [130] |
Yuge et al. 2017 | 4 | 10-24f | Pilot open-label | Ghrelin | Not measured | • SDCF to assess clinical and neurological parameters • BFMDRS score to assess dystonia • VAS | Following treatment, improvement in scores were noted for: • SDCF for Patient 1 (31 [baseline] to 29 [2 years]) and Patient 2 (20 [baseline] to 18 [10 months]) • BFMDRS for Patient 1 (108.5 [baseline] to 100 [2 years]) and Patient 2 (67 [baseline] to 54.5 [10 months]) • Change in baseline in VAS for dystonia, tremor and sympathetic vasomotor reflexes in patient 1 and 2. | [129] |
Nissenkorn et al. 2017 | 14 | 6 (planned) | Open-label (Phase 2) | Glatiramer Acetate | Noninvasive respiratory inductance plethysmography | Primary: • Safety, tolerability of treatment • Decrease in epileptiform activity Secondary: • Seizure frequency • Improvement in respiratory dysfunction • Improvement in core features assessed by Kerr and Naidu validated severity scores) | Study was terminated due to treatment related serious adverse events in four patients. | [128] |
Djukic et al. (2016) | 10 | 6 | Open-label (Phase 2) | Glatiramer Acetate | • Xltek, Sleep Monitoring • Tobii T300 Eye Tracker • EEG | Primary: • Change in gait velocity (primary) Secondary: • Change in respiratory and cognitive functions, • Change in QOL measures (assessed using Child Health Questionnaire-P50) and • Change in EEG parameters | No statistically significant changes in QOL were observed, however, following glatiramer acetate treatment, improvements were noted for: • Gait velocity (13–95% improvement [p = 0.03]) • Memory and breath holding index (p ≤ 0.03) | [127] |
Fabio et al. (2016) | 34g | N/A | Observational | Cognitive training | • Eye-tracking • EEG | Functional and cognitive descriptive of sample using functional scales, matrices, eye tracking and EEG assessment. | Longer term (5 days) cognitive training appears to improve behaviour and brain parameters in RTT patients. | [126] |
Pini et al. (2016) | 10 | 6 | Open-label | IGF-1 (full length) | EEG | • ISS • RSS | Significant improvements seen in ISS (p = 0.0106) and RSS (p = 0.0274) outcome measures for the treatment group. | [125] |
Khwaja et al. (2014) | 12 | 1 MAD 5 OLEh | Open-label (Phase 1) | IGF-1 (full length) | • BioRadio • EEG | • Apnoea Index • Hyperventilation Index • MBA • RSBQ • ADAMS • EEGs | Following IGF-1 treatment, improvements were noted for: • Apnoea from Pre-MAD to Post-OLE (Apnoea index −7.12 ± 4.58 [mean ± SE]) • RSBQ (fear/anxiety subscale: − 0.79 [mean difference from visit 1 of OLE to visit 5 of OLE]), • ADAMS (social avoidance subscale: − 1.44 [mean difference from visit 1 of OLE to visit 5 of OLE]), • Reversal of right-sided alpha band frontal EEG symmetry | [124] |
Signorini et al. (2014) | 24i | 12 | Randomised, controlled study | ω-3 PUFAs | N/A | Examination of erythrocyte fatty acid profile | Improvements seen in ω-6/ω-3 ratio, serum lipid profiles as well as normalisation of inflammatory markers and reduction in bone hypodensity and PUFS peroxidation following ω-3 PUFA supplementation compared to the untreated group. | [123] |
Maffei et al. (2014) | 66j | 12 | Randomised, placebo controlled single-blind | ω-3 PUFAs | Echocardiography | Measurement of oxidative stress biomarkers and ECG parameters | Improvements were noted in biventricular myocardial systolic parameters following ω-3 PUFAs treatment in comparison to placebo. | [122] |
Hagebeuk et al. (2013) | 10 | 26 | Randomised, placebo controlled, double-blind crossover | Folinic acid | N/A | Measurement of CSF, folate metabolite and SAH/SAM ratio | N/A | [121] |
De Felice et al. (2012) | 20 | 6 | Randomised, placebo controlled single-blind | ω-3 PUFAs | Respiratory polygraphy using Somnowatch | Primary • CSS • Respiratory dysfunction • Video clips pre-& post treatment Secondary • Reduction in oxidative stress markers following treatment | Although respiratory dysfunction improved after 6 months of treatment no significant changes were detected in autonomic symptoms as assessed by the CSS. | [120] |
Pini et al. (2012) | 6 | 6 | Open-label pilot | IGF-1 (tripeptide form) | • Neuroscope • ECG • EEG | • Autonomic parameters evaluated were cardiac vagal tone, HR, transcutaneous blood gases, and trends in respiration • ISS parameters (growth and development, locomotor apparatus, locomotor ability, cortical and autonomic functions) • EEG measurements | Safety and tolerability study – no statistically significant changes were reported in cardiac function (ECG, HR and vagal tone) or in all ISS parameters during IGF-1 treatment. | [119] |
Hagebeuk et al. (2012) | 8 | 26 | Randomised, placebo controlled double-blind crossover | Folinic acid | N/A | • Plasma folate measurement • MBA • Hand Apraxia Scale • Parental Overall Well-Being Index | No statistically significant differences were found for neurological features, Hand Apraxia Scale or the MBA | [118] |
Hagebeuk et al. (2011) | 12 | 24 | Randomised, placebo controlled, double-blind crossover | Folinic acid | EEG | Change in seizure frequency and EEG | Benefits only noted in 3 patients on folinic acid. | [117] |
Freilinger et al. (2011) | 21k | 13 | Double-blind, randomised, placebo-controlled crossover | Creatine | N/A | • Change in global DNA methylation • Change in RTT specific symptom score as defined by MBA | No statistically significant changes in either the total or sub-scores of the MBA | [116] |
Signorini et al. (2011) | 42l | 12 | Open-label pilot | ω-3 PUFAs | N/A | Measurement of oxidative stress biomarkers | N/A | [115] |
Leoncini et al. (2011) | 42 | 12 | Open-label pilot | ω-3 PUFAs | N/A | Measurement of oxidative stress biomarkers | N/A | [114] |
Temudo et al. (2009) | 25 | 6 | Open-label in patients with low levels of folate metabolite | Folinic acid | N/A | Measurement of folate metabolites and CSF neurotransmitters | N/A | [113] |
Glaze et al. (2009) | 73 (68) | 12 | Randomised double-blind, placebo-controlled | Folate–betaine | Polygraphic measurements of breathing patterns, hand stereotypies and qualitative EEG | • Growth parameters (weight, height, BMI, and head circumference • EEG • MBA • Parent questionnaire | No objective improvements reported, however, subjective improvement based on a parent questionnaire was noted for the < 5 years age group. | [112] |
Wilfong & Schultz (2006) | 7 | 12 | Case series | Adjunctive vagus nerve stimulation (VNS) for treatment of epilepsy | Vagus nerve stimulation device | • Seizure frequency • Effect of VNS therapy on caregiver reported hyperventilation, breath holding, swallowing dysfunction, mood and communication. | • Improvements were noted in seizure frequency and in alertness. • No significant change in either mood or communication parameters following VNS therapy. | [111] |
Guideri et al. (2005) | 10m | 6–18 months (follow-up) | Randomised blinded study | Acetyl-L-carnitine | ECG parameters | • Heart rate variability • QTc interval • QTc dispersion | Increased heart rate variability was observed in the treatment group. | [110] |
Gorbachevskaya et al. (2001) | 9 | 20–40 daysn | Open-label pilot | Cerebrolysin | EEG | Quantitative EEG to monitor motor and cortical functions. | Modest improvements in motor and higher cortical functions in patients treated with cerebrolysin. | [109] |
Ellaway et al. (2001) | 21o | 6 | Open-label | L-carnitine | N/A | • RS: SSI • Hand Apraxia Scale • 7 day-night sleep diary • SF-36 Health Survey | Improvements noted in sleep efficiency (P = 0.027), expressive speech (P = 0.011), communication skills (P = 0.004) and energy levels (P < 0.005) in the treatment group in comparison to the control group. | [108] |
Ellaway et al. (1999) | 35 | 6 | Randomised placebo controlled double-blind crossover | L-carnitine | N/A | • MBA • Hand Apraxia Scale • Patient Well-Being Index | • No measurement of autonomic function. • Small improvements in patients’ well-being and hand apraxia scale in the L-carnitine treatment group. | [107] |
McArthur and Budden (1998) | 9 | 2.5 | Randomised placebo controlled double-blind crossover | Melatonin | Actigraphy (measures of sleep parameters) | Sleep parameters | • Melatonin decreased sleep onset (19.1 ± 5.3 min [mean ± SE]) in comparison to baseline (42.1 ± 12.0 min [mean ± SE]). • Other improvements were noted in total sleep time and sleep efficiency. | [106] |
Stenbom et al. (1998) | 12 | ~ 3-5p | Open-label pilot | Lamotrigine | EEG | • Seizure frequency • Motor skills • Safety and tolerability monitoring | Some improvements were noted in with lamotrigine regarding seizure frequency, alertness and concentration. | [105] |
Percy et al. (1994) | 25q | 9 | Randomised placebo controlled double-blind crossover | Naltrexone | EEG polygraphy that assessed sleep, respiratory characteristics and hand stereotypies. | • Neurophysiological parameters (assessment of sleep, respiratory characteristics and hand stereotypies). • Measurement of CSF and β endorphin | • Statistically significant differences were noted for a higher awake minimum O2 saturation (P = 0.03) and less time spent on disordered breathing (P = 0.02) in the naltrexone treatment group in comparison to the placebo treatment group. • No changes in EEG and sleep characteristics between the treatment and placebo group. | [104] |
Nielsen et al. (1990) | 11r | ~ 6 | Randomised double-blind crossover | Tyrosine and tryptophan | EEG | • Parent interviews and observation forms to assess child behaviour. | No clinical improvement. | [103] |
Zappella (1990) | 10 | 4 | Placebo controlled double-blind partial crossover | Bromocriptine | N/A | • Portage guide items for the assessment of motor, social and cognitive skills. | • In the treatment group, improvements in Portage guide items for motor, social and cognitive activities were noted for 2 subjects and minor improvement in 1 subject. • 7 subjects showed no change to treatment. | [102] |
Haas et al. (1986) | 7 | 2–6 | Open-label uncontrolled treatment trial | Ketogenic diet | • EEG • Transthoracic impedance to assess respiratory characteristics (central apnoea). | Changes in: • EEG • Respiratory monitoring • Clinical laboratory values | Clinical improvements noted in: • Seizure control, • Respiratory function, • Behavioural and motor control. | [101] |