Objective: To identify factors associated with treatment efficacy and safety of unilateral thalamic magnetic resonance-guided focused ultrasound (MRgFUS) in patients with essential tremor (ET).

Background: MRgFUS is an established treatment for ET, but predictors of response and adverse events (AEs) remain poorly characterized.

Method: Single-center ambispective registry of 187 ET patients who completed unilateral thalamic MRgFUS with a follow-up of 12 months. Efficacy was assessed using the Clinical Rating Scale for Tremor (CRST). Quality of Life in Essential Tremor (QUEST) at 6 and 12 months was also evaluated. An excellent treatment response was defined as ≥80% reduction in treated side CRST score. AEs were registered at all timepoints. Gait disturbances were evaluated using the Scale for the assessment and rating of ataxia (SARA) and the Timed Up and Go test (TUG). Longitudinal changes were analyzed using linear mixed models. Factors associated with sustained response (≥80% CRST treated side reduction at ≥2 visits) and persistent AEs (≥2 visits from 3 months onward) were identified using logistic regression models.

Results: CRST subscore of the treated side was reduced by 79.5% at 12 months, and 70 (60.3%) patients were excellent/very good responders at 12 months (p<0.001). Sustained response was achieved in 50.9% (≥2 follow-up visits) of patients. QUEST scoring improved by 53.2% at 12 months (p<0.001). Transient axial ataxia peaked at 7 days (SARA axial +122%, p<0.001) with full recovery by 3 months. Fall risk was significantly reduced at 6 and 12 months (p=0.04 and p=0.004, respectively). Persistent AEs occurred in 26.1% of patients and 20.7% at 12 months, with instability (9.5%) and dysarthria (5.2%) being the most frequent. Lower baseline CRST-B score was associated with sustained response (OR=0.94, 95%CI 0.89–0.99, p=0.028) but more persistent AEs (OR=0.93, 95%CI 0.87–0.99, p=0.032). Female sex was associated with higher response at 12 months (OR=4.35, 95%CI 1.82-11.11, p=0.002). Active smoking showed a trend toward more persistent AEs (OR=2.84, 95%CI 0.85-11.2,p=0.099).

Conclusion: Unilateral thalamic MRgFUS achieves sustained tremor reduction with an acceptable safety profile. Lower baseline tremor severity predicts both better efficacy but paradoxically more persistent AEs. Female sex and active smoking are potential modulators of outcomes warranting further investigation.

« Back to 2026 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/factors-associated-with-efficacy-and-safety-of-unilateral-thalamic-mrgfus-in-essential-tremor-a-single-center-cohort-study/