Objective tremor monitoring using tri-axis accelerometer in MRgFUS thalamotomy for essential tremor: a feasibility study

Background: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy has shown promising results in treating pharmaco-resistant essential tremor (ET). This incisionless, image-guided technique targets the ventralis intermedius nucleus of the thalamus with precision, sparing surrounding eloquent tissue. Objective: This study aims to assess the efficacy of MRgFUS thalamotomy in improving tremor among ET patients, as objectively measured by a tri-axis accelerometer, and to compare these objective measures with the conventional Clinical Rating Scale for Tremor (CRST). Design: Prospective observational study. Methods: Ten ET patients (aged 68.1 ± 11.8 years) received the MRgFUS treatment. Improvements in tremor severity were assessed using primary (CRST), with additional measurements of kinematic feature obtained from a tri-axis accelerometer. Correlations between accelerometer-derived kinematic features and CRST scores were evaluated. Results: Significant improvement in tremor severity was observed in the cohort, as measured by both the accelerometer and CRST (paired Student’s t test, p < 0.05) before and 1 day after the treatment. A moderate-to-strong correlation was found between accelerometer measurements and CRST scores. Conclusion: The tri-axis accelerometer provides an effective means of monitoring tremor reduction following MRgFUS and correlated well to the clinical scales like CRST. This study supports the feasibility of accelerometer-based monitoring in clinical practice for MRgFUS assessment.