Continuous tremor monitoring in Parkinson's disease: A wristwatch-inspired triboelectric sensor approach.

Parkinson's disease (PD) prevalence is projected to reach 12 million by 2040. Wearable sensors offer a promising approach for comfortable, continuous tremor monitoring to optimize treatment strategies. Here, we present a wristwatch-like triboelectric sensor (WW-TES) inspired by automatic watches for unobtrusive PD tremor assessment. The WW-TES utilizes a free-standing design with a surface-modified polytetrafluoroethylene (PTFE) film and a stainless-steel rotor within a biocompatible polylactic acid (PLA) package. Electrode distance is optimized to maximize the output signal. We propose and discuss the WW-TES working mechanism. The final design is validated for activities of daily living (ADLs), with varying signal amplitudes corresponding to tremor severity levels ("normal" to "severe") based on MDS-UPDRS tremor frequency. Wavelet packet transform (WPT) is employed for signal analysis during ADLs. The WW-TES demonstrates the potential for continuous tremor monitoring, offering an accurate screening of severity and comfortable, unobtrusive wearability.