Added value of a wrist-worn device for assessing tremor in Parkinson's disease: reliability and validity of tremor evaluation at home.

Clinical assessment and self-report of tremor in Parkinson's disease (PD) have several limitations, including recall bias and lack of sensitivity. Wearable-based technology offers an opportunity to address these shortcomings. We investigated the test-retest reliability of wearable tremor assessment and compared the different approaches of assessing tremor. We analyzed data from 219 participants of the ProPark study. In 27% of people with PD, self-report and clinical observation disagreed about the presence of tremor. Wearable-based tremor assessment had excellent test-retest reliability after 3 days of data recording (ICC(2,3) lower bound of 95%CI > 0.90 for all tremor metrics). Wearable-derived tremor amplitude, duration, and volume were significantly associated with clinical assessment of tremor (all p < 0.001), and tremor volume was consistent with patient self-report of tremor presence when clinical observation failed to detect tremor (p = 0.040). In conclusion, wearable sensors can provide accurate and relevant information about the presence and severity of tremor in PD.