Abstract
Background:
Parkinsonism is a group of progressive neurological conditions which are often characterised by movement impairments such as bradykinesia, tremor, rigidity and postural instability. It has long been known that people with parkinsonism also experience non-motor symptoms such as affective symptoms, sleep disturbances, cognitive difficulties, fatigue, and pain, yet it is only in the past two decades that research has begun to focus on these symptoms . Non-motor symptoms can fluctuate within and between days and have a negative impact on independence, daily routines, planning, and socialisation. It is, therefore, not surprising that these symptoms also negatively affect health-related quality of life. Compared to motor symptoms, non-motor symptoms remain under-appreciated and under-researched, contributing to a limited understanding of their complex presentation. While there is growing evidence from exercise intervention trials reporting potential improvements in non-motor symptoms, there are no established guidelines for managing these symptoms in terms of physical activity type, duration, intensity, and frequency. Furthermore, physical activity levels in this population typically decline following diagnosis, and sustaining exercise may become increasingly challenging due to disease progression and age-related changes. Many people with Parkinson’s are not meeting current physical activity guidelines.(12) Encouraging increased participation in free-living physical activities may offer a more feasible and sustainable approach to managing non-motor symptoms throughout disease progression. Free-living physical activities are defined as incidental or planned leisure activities which one completes during their free time based on personal interests (e.g., gardening, dance, walking), non-leisure activities based on needs such as transportation (e.g., cycling) and occupational activities, or planned forms structured exercise which are integrated into a person’s daily or weekly routine.(16, 17)
Aim:
The overall aim of the thesis was to explore associations among non-motor symptoms, pertaining to cognition, sleep disturbances, anxiety, depression, apathy, fatigue, and pain, and their relationship with free-living physical activities in people with Parkinson’s disease.
Methods and results:
The thesis comprised four projects: two independent systematic reviews with meta-analyses, which synthesised the current literature relating to (1) the interactive relationships among cognition, affective disorders, sleep disturbances, fatigue, and pain in people with Parkinson’s disease and (2) the association of these symptoms with free-living physical activities. Two subsequent studies were conducted to further explore these associations in people with Parkinson's in New Zealand. One study used ecological momentary assessments (EMA), which employs a repeated longitudinal sampling design to collect data over time. The second study used a qualitative approach, conducting focus groups to gain deeper insights into these associations.
The review observed significant associations among all non-motor symptoms explored, with nocturnal sleep disturbances, affective disorders, and fatigue potentially playing a central role in the coexistence of other presenting symptoms. The second review identified that participation in free-living physical activities is related to better cognition and reduced anxiety, apathy, and depression. However, many of the reports included in these reviews used retrospective measures to assess non-motor symptoms and physical activity, measures that are inherently subject to recall bias and serve more as proxy measures than absolute measures.
To address this limitation, the validity and feasibility of a newly developed ecological momentary assessment (EMA) protocol, designed to evaluate non-motor symptoms and physical activity behaviours in people with Parkinsons was evaluated. An exploratory Spearman’s rank correlation analysis was conducted to investigate associations among non-motor symptoms and their relationship with physical activity. Consistent with the review findings, positive associations were identified among cognition, affective disorders, sleep disturbances, fatigue, and pain. Furthermore, greater participation in physical activity was associated with better cognition and reduced feelings of anxiety, depression, and fatigue.
The feasibility of EMA was demonstrated by a high compliance rate of 98.9% among smartphone users (n = 36) and 69.3% among paper diary users (n = 9), and a retention rate of 100%. Overall, participant feedback for EMA was positive, indicating that the number of EMA prompts and the duration of the data collection period were feasible. Participants also found the questions relevant, comprehendible and comprehensive. Convergent validity of the EMA was established against commonly used standardised self-reported measures, using Spearman’s rank correlations (rs range = 0.32 to 0.65). Furthermore, preliminary analyses highlighted the utility of EMA to evaluate relationships between non-motor symptoms and physical activity, particularly at an individual participant level.
The qualitative study comprised four semi-structured focus groups with a subsample of participants from the EMA study. Discussions were focused on the experiences and perceptions of people with Parkinsons, particularly in relation to non-motor symptoms and the potential role of physical activity in managing the disturbances imposed by the condition – under three key objectives (Living with Parkinsons; Relationship between physical activity and non-motor symptoms; Associations among non-motor symptoms). Inductive thematic analysis, using a cut-and-paste approach, was used to organise and report findings conveyed in the qualitative data. Themes were presented under the each objective to add structure and clarity to the findings. Under the objective ‘Living with Parkinsons,’ three themes were identified: ‘This is not me, but it is me now,’ ‘Cut yourself some slack – but don’t give up,’ and ‘You’re not alone.’ Under the objective ‘Relationship between physical activity and non-motor symptoms,’ three themes were identified: ‘Physical activity helps…but it’s different for everyone,’ ‘When I’m not active I feel it,’ and ‘Trying to stay active, even when it’s hard.’ Under the final objective of ‘Associations among non-motor symptoms,’ two themes were identified: ‘When thinking clearly helps – but thinking gets harder,’ and ‘Sleep is all over the place – but I still get on with things.’
Conclusion:
The findings of this thesis provide compelling evidence of the complex interactive associations among non-motor symptoms and their relationship with free-living physical activities in people with Parkinson’s disease. These insights support clinicians in encouraging this population to initiate and maintain regular physical activity in their daily lives not only to manage physical symptoms, but also to manage non-motor symptoms, particularly cognitive difficulties, anxiety, depression, and apathy. Further, this research supports the utility of EMA as an effective tool for assessing non-motor symptoms and physical activity behaviours in people with Parkinson’s, demonstrating both its feasibility and validity.