Relationship Between Each of the Four Major Motor Symptoms and At-Home Physical Activity in Individuals with Parkinson's Disease: A Cross-Sectional Study.

Background/Objectives: Individuals with Parkinson's disease (PD) often experience four major motor symptoms-tremor, rigidity, bradykinesia, and postural instability/gait disorder. Although these symptoms have been shown to affect activities of daily living, their impact on the level of at-home physical activity (PA) in this population remains unexplored. We aimed to investigate the relationship between the four major motor symptoms of PD and at-home PA in these individuals. Methods: This retrospective cross-sectional study included 17 individuals with PD. We examined the relationship between the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale Part 3 score and the time spent in three PA intensities (sedentary behavior, light PA [LPA], and moderate-to-vigorous PA) within the home. Pearson's correlation coefficient was used for statistical analysis. Results: In the initial step analysis, a significant negative correlation was observed between the overall motor symptom score and the time spent in LPA inside the home (r_s [95% confidence interval]: -0.72 [-0.93 to -0.25]; p < 0.01). In the second step analysis, a significant negative correlation was observed between the bradykinesia score and the time spent in LPA inside the home (r_s: -0.74 [-0.92 to -0.30]; p < 0.01). Conclusions: Among the four major motor symptoms, only the severity of bradykinesia influenced the time spent in LPA inside the home. Thus, rehabilitation treatment focusing on bradykinesia may be beneficial for increasing the time spent in LPA inside the home for individuals with PD.