Contribution of Axial Motor Impairment to Physical Inactivity in Parkinson Disease

Objective The objective of this study was to investigate the relationships between motor symptoms of Parkinson disease (PD) and activity limitations in persons with PD. Design/Methods This is a cross-sectional study of persons with mild to moderate PD (N = 90). Associations among axial motor features, limb motor signs, the Physical Activity Scale for the Elderly, the ability to perform Activities of Daily Living (ADLs), and level of ADL dependency were studied. A composite score of axial motor features included the following Unified Parkinson Disease Rating Scale items: speech, rigidity of the neck, arising from chair, posture, gait, and postural stability. A composite score of limb motor signs included the following Unified Parkinson Disease Rating Scale items: tremor at rest of all extremities, action tremor, rigidity of all extremities, finger taps, hand movement, rapid alternating hand movements, and foot tapping. Results Axial motor features of PD were significantly correlated with physical inactivity (P < 0.001), decreased ADL (P < 0.001), and increase in ADL dependency (P < 0.001). Limb motor signs significantly correlated with decreased ADL (P < 0.001) and level of ADL dependency (P = 0.035) but did not correlate with physical inactivity. After controlling for age, sex, disease duration, and comorbidity, axial motor features contributed significantly to physical inactivity, decreased ADL, and increase in ADL dependency, whereas the limb motor signs did not. Conclusions Axial motor impairment contributed to physical inactivity and decreased ability to perform ADLs in persons with PD.