Effects of Mental Imagery With Self-regulation on Daily Activities in People With Parkinson's Disease

With less dopamine in the substantia nigra of the basal ganglia, People with Parkinson's Disease (PwPD) experience symptoms across a spectrum. This causes impairment of their supervisory attentional system (SAS), affecting the person's mental flexibility and ability to focus attention on movements and leading to a reliance on slow and energy-intensive action. As a result, PwPD have many restrictions not only in gait and walking but also in completing routine daily activities such as bathing and shopping.

Conventional rehabilitation, such as exercise, targets their motor issues and enhances mobility. However, exercise may not directly work on SAS impairment and non-motor symptoms and, therefore, may only produce short-term benefits. Cueing is another strategy that facilitates motor performance in PwPD by shifting attention resources to compensate for movement initiation and sequencing. Our previous systematic review and meta-analysis showed that cueing improved task performance in PwPD with a lasting effect from 1 week to 1 year. However, cueing relies on an external cue and device, which is unrealistic for daily and community living and specific to a particular task, such as walking. Generalisation to other daily activities is limited.

The use of Mental Imagery (MI) is a rehabilitation strategy that has been studied to improve function in PwPD. MI works under a cognitive mechanism that tackles the SAS impairment and improves the attentional focus required in learning movement strategies. However, conflicting results in the use of MI in PwPD have been found. When reviewing the intervention protocols of clinical trials with positive results, the intervention broke tasks into steps, engaged participants in self-awareness of their own problems, or drew attention toward task performance during mental imagery. Drawing attention toward task performance seems to work using a cognitive approach to tackle SAS impairment and improve the attentional focus required in learning movement strategies. Modification of MI intervention protocols by adding an extra component to enhance attentional focus when learning movement strategies and engaging them in understanding the motor demand based on their ability are hypothesised to be the key to guaranteeing the success of these MI intervention protocols. Self-regulation is a strategy that can offer this extra component.

Self-regulation has been used widely in education to enhance learning. It involves self-monitoring and self-modification of one's behaviour. In rehabilitation, self-regulation has been shown to enhance participation in daily activities in people with stroke. Using a cognitive approach, self-regulation is an active learning strategy that helps individuals to be aware of their own ability and environment and control their own learning. Self-regulation and executive function are connected theoretically and empirically. Both involve the processes of (1) organising/prioritising; (2) focusing/sustaining; (3) regulating alertness; (4) managing frustration and emotion; (5) utilising working memory and recalling; and (6) monitoring and self-regulating action. This is achieved by the person monitoring their own performance, identifying their solutions and reflecting on their success. Apart from people with stroke, the Principal Investigator and the team also demonstrated the effective use of self-regulation in autistic children in learning school and daily activities.

Our previous studies demonstrated the effective use of MI with self-regulation in improving the daily activities in people with stroke, with 1-month carry-over effects and generalisation to untrained daily activities. Our research showed that combining MI with self-regulation could improve attention and sequencing-processing abilities and monitoring of daily activity performance by self-reflecting on successful performance in people with stroke. The cognitive processes in understanding one's abilities and deficits, analysing the demands in each step of a task, and planning and imagining performing the individual task steps will allow PwPD to process all the cognitive and motor demands as well as their own abilities in coping with these task demands.

Based on our previous research on stroke, we developed a MI with self-regulation program for PwPD (MI-SeR) with feedback from two consumer co-designed workshops with five health professionals and five PwPD and their carers and pilot-tested it on 11 patients with mild to moderate PD. The MI-SeR was shown to have satisfactory feasibility (85% completed the intervention program) and excellent acceptability, with all participants who completed the program agreeing that they would recommend it to other PwPD. After the 6-week MI-SeR, there were significant improvements in patient-rated perceived daily activities and a medium effect size as measured by the Canadian Occupational Performance Measure (p = .011, effect size = .47), and attention and mental flexibility of cognitive function, also with medium effect sizes, as measured by the Trail Making A and Trail Making B, respectively (p ≤ .05, effect size = .59; p = .022, effect size = .69).

Objectives

1. Primary objective To investigate the effects of MI with self-regulation (MI-SeR), compared with conventional learning and exercise (control intervention), on improving patient-rated perceived performance of daily activities in PwPD.
2. Secondary objective To assess the effects of the two interventions on daily functioning, cognitive function, and motor function in PwPD.
3. Exploratory objective To explore whether MI-SeR is associated with changes in fNIRS-measured cortical haemodynamic responses during ADL-related MI tasks, and whether the intervention effects on daily activity performance are mediated through improvements in prefrontal executive function quantified by fNIRS-assessed cortical activity.