Wearable Inertial Sensor Analysis of Turning Performance Reveals Motor Reserve Effects in Drug-Naïve Parkinson’s Disease

Introduction: Motor reserve (MR) has been hypothesized as a protective factor against age-related and pathological motor decline, potentially enhancing quality of life. This study aimed to investigate the influence of MR on motor performance, assessed via mobile health technology (MHT), in drug-naïve Parkinson’s disease (PD) patients. Methods: Consecutive drug-naïve PD patients and age-matched healthy controls (HC) underwent cognitive and motor assessments. Turning MHT parameters were extracted from the Timed Up and Go test (TUG) performed at self-selected and fast speeds. Participants were categorized into high- or low-MR groups based on the Motor Reserve Index questionnaire (MRIq). Results: Forty-five PD patients and forty healthy controls (HC) were enrolled. PD patients showed longer TUG durations and altered performance compared to HC. No differences were found between high and low motor reserve (MR) groups in demographics or clinical severity. However, high-MR patients exhibited shorter turn duration and higher angular velocities at both self-selected (p < 0.005) and fast speeds (p < 0.05). MR subdomains related to physical and care activities correlated with MHT turning metrics, unlike housework and leisure domains. Conclusions: the findings highlighted the relevance of MR on motor performances assessed by MHT in drug naïve PD, independently from motor severity.