Validation of a smartphone-based tremor measurement tool for Parkinson's disease.

This study validates a smartphone app for hand tremor assessment in Parkinson's disease (PD). Twenty-eight PD patients performed a weekly tremor test using the app while wearing a wrist-worn actigraphy device (GeneActiv), of which twenty-one yielded usable actigraphy data for comparative analysis. Features were extracted from both devices to compare smartphone application derived data against actigraphy measurements. Further analysis examined the validity of the smartphone data in ON versus OFF medication states and against clinical scales (MDS-UPDRS). Statistical tests show high correlations between the app and GeneActiv features whereas app-derived features show statistical significant differences on data between medication states (p < 0.05), and correlations (maximum correlation 0.47) with clinical scores (MDS-UPDRS). The findings support the clinical validity of smartphone-based tremor assessments in PD, which shows potential for ongoing symptom monitoring in individuals with PD from at-home environments.