Abstract:  

Sleep problems in Parkinson?s disease (PD) are among the most prominent non-motor symptoms of the disease. Sleep fragmentation, sleep latency, reduced sleep efficiency, and excessive daytime sleepiness have all been frequently reported in this population. In older adults it has been found that sleep quality is associated with physical function. However, it is unclear if there is any association between sleep quality, physical function and physical activity in Parkinson?s disease. Purpose: The purpose of this study was to examine whether sleep quality is associated with physical function and physical activity in individuals with early to mid stage idiopathic PD. Methods: Cross-sectional observational study design was used. Twenty-one individuals with Parkinson?s disease (mean age? SD, 60.3 ? 13.1 years; Hohen & Yahr mean ? SD, 2.4 ? 0.92 units) participated in this study. Physical function was assessed using 30 second Chair sit to stand test (30s CST). Physical Activity was assessed objectively using a tri-axial accelerometer that was worn around the waist for 7 consecutive days. The percentage of moderate to vigorous physical activity that was derived from the tri-axial accelerometer was used in the analysis. Sleep was assessed subjectively using the Pittsburg Sleep Quality Index (PSQI). Subscales of PSQI (subjective sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbance, daytime dysfunction and use of sleep medications) were evaluated. Pearson correlation was used to examine the association between various components of PSQI, physical function and physical activity measures. Regression analysis was used to model the association between the sleep, physical function and physical activity measures. Results: In bivariate analyses, sleep latency (i.e., the length of time that it takes to accomplish the transition from full wakefulness to sleep), was found to be associated with chair sit to stand (p=0.03) and percentage of moderate to vigoro