Secondary outcomes
The assessment of secondary outcomes will assist in determining the most appropriate outcome measures to be used for a larger trial. For people with PD dementia, these cover the domains of cognition, mood, behaviour, everyday functional activity, motor severity, quality of life, self-efficacy and carer ratings (where available) of patients’ performance on goals identified during the BGSI. Within-group data from CR sessions on goal setting and performance will be assessed to give information on factors such as the types of goals that participants choose and which types of goals are addressed most effectively through the therapy. Also, for the CR group, patients, their carers and the therapist will make in-session ratings of goal attainment to provide concurrent evidence regarding changes in goal performance. Differences between these ratings of the patient’s goal attainment will also be examined across the rater groups. Carers’ outcomes include quality of life, stress and health.
Regarding cognition, global cognition will be measured using the ACE-III [
23]. Assessments of executive function will be the Trail Making Test (TMT) and the letter fluency tests from the Delis-Kaplan Executive Function System (DKEFS) [
26]. Attention will be assessed using the Test of Everyday Attention (TEA) [
27]. Memory will be assessed using the Rivermead Behavioural Memory Test (RBMT) [
28], Story Recall subtest.
Mood will be assessed using the Hospital Anxiety and Depression Scale (HADS), which contains subscales for anxiety and depression and is validated in PD [
29].
Behavioural assessment will include delusions and hallucinations measured using the Neuropsychiatric Inventory Questionnaire (NPI-Q) [
30]. The Unified Parkinson’s Disease Rating Scale (UPDRS) [
31] will be used to assess the motor symptoms of parkinsonism in PD and DLB (part 111) and also to assess function and activities of daily living.
Quality of life will be assessed in PD and DLB using the abbreviated Parkinson’s Disease Questionnaire (PDQ-8) [
32] and, in order to have a direct comparison, the World Health Organisation Quality of Life – BREF (WHOQOL-BREF) [
33], which has been validated in PD [
34,
35] will also be used with carers.
In order to assess a general sense of perceived self-efficacy, the potential to influence one’s situation through one’s own actions, the General Self-Efficacy Scale (GSE) [
36] will be used.
The BGSI also requires carers to rate the patients’ level of performance on a 1 – 10 scale (1 = unable to perform; 10 = fully able to perform). Carer ratings will be recorded at the baseline, post-intervention and follow-up researcher visits.
For the CR group only, a simplified goal attainment scaling procedure [
37] will be used to obtain in-session ratings of the patient’s goal attainment by the participant, the carer and the therapist. These will be obtained at the first, fourth and eighth (final) therapy sessions.
Carers’ stress will be assessed using the 15-item dementia-specific Relatives Stress Scale (RSS) [
38].
Service receipt during the intervention period, including dementia-specific services, monitoring, and interventions provided by movement and memory clinics, will be documented for all participants. All participants will be free to access services such as those offered by Parkinson’s UK, and the extent of this will be recorded.
Cost-effectiveness will be piloted using measures of health status, the EQ-5D-3 L [
39]. We will develop and use a Client Service Receipt Inventory (CSRI) [
40] specific to this patient group that can be used later in a full trial to assess health care utilisation. Other information collected will include gender, age, the relationship between the person with PD dementia and their carer and whether they live together, age of onset of PD, PD dementia, or DLB, Hoehn and Yahr PD severity [
41]. Medication, educational level, social class, and co-morbidities will be recorded to examine effects of demographic and social variables on treatment efficacy.