Distinct gait dimensions are modulated by physical activity in Parkinson's disease patients

Parkinson's disease (PD) is the fastest growing neurodegenerative disease, but disease-modifying or preventive treatments are lacking. Physical activity is a modifiable factor that decreases the PD risk and improves motor symptoms in PD. Understanding which dimensions of gait performance correlate with physical activity in PD can have important pathophysiological and therapeutic implications. Clinical/demographic data together with physical activity levels were collected from thirty-nine PD patients. Gait analysis was performed wearing seven inertial measurement units on the lower body, reconstructing the subjects' lower body motion using 3D kinematic biomechanical models. Higher physical activity scores were significantly correlated with MDS-UPDRS part III scores (r = - 0.58, p value = 9.2 × 10^-5), age (r = - 0.39, p value = 1.5 × 10^-2) and quality-of-life (r = - 0.47, p value = 5.9 × 10^-3). Physical activity was negatively associated with MDS-UPDRS part III scores after adjusting for age and disease duration (β = - 0.08530, p value = 0.0010). The effect of physical activity on quality-of-life was mediated by the MDS-UPDRS part III (62.10%, 95% CI = 0.0758-1.78, p value = 0.022). The level of physical activity was correlated primarily with spatiotemporal performance. While spatiotemporal performance displays the strongest association with physical activity, other quality-of-movement dimensions of clinical relevance (e.g., smoothness, rhythmicity) fail to do so. Interventions targeting these ought to be leveraged for performance enhancement in PD through neuroprotective and brain network connectivity strengthening. It remains to be ascertained to which extent these are amenable to modulation.