Analyzing the Effects of Parameters for Tremor Modulation via Phase-Locked Electrical Stimulation on a Peripheral Nerve

A Wearable In-home Tremor Assessment System via Virtual Reality Environment for the Activities in Daily Lives (ADLs)

Currently available diagnostic methods for tremor movements are mostly subjective measurements, and clinicians and researchers typically diagnose patients' symptoms with provocative maneuvers, and the inter-rater and intra-rater variabilities of those methods have been always reported. Even though various sensor-based quantitative approaches have been explored, most of the tools are limited to the tremor metrics (i.e., severity and frequency). A consistent environment that can provide a test setup to evaluate how their performance is affected by the tremor movement for activities of daily living would be needed for a smart tremor diagnosis. Therefore, we developed a virtual reality environment with a custom designed wearable sensor module to quantify tremor characteristics with performance-based assessment while they perform the activities of daily living, and correlated the performance to existing tremor scores (i.e., The Essential Tremor Rating Assessment Scale (TETRAS)). We evaluated this approach with five healthy participants (no tremor), and applied an artificial tremor using a vibration motor to mimic tremor movements as a pilot study. We analyzed three categorized tremor scenarios: resting, postural, and kinetic tremor tasks using six different tasks in virtual 3D space. All the artificial tremor was score as TETRAS=1, and we successfully analyzed the tremor metrics for different tasks by comparing them with TETRAS score, and verified the different tremor characteristics with the artificial tremor. Additionally, we analyzed the performance of 3D spiral drawing on the virtual reality track using "outside area" and "completion time" as the accuracy and speed of the performance. Clinical Relevance- This can be applied to quantify and track the tremor symptom at the patients' home, and ultimately this method can be synchronized with their current treatment parameters (i.e., dosage of medication, and parameters of the stimulation) to optimize/maximize the effect of treatment.