Dysgeusia and Numbness after MRgFUS Thalamotomy for Tremor

Introduction: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is increasingly utilized to treat refractory ET and TdPD. Dysgeusia after MRgFUS has been described, with current studies reporting prevalences of 4%-13% at 1-3 months post treatment. We hypothesized that dysgeusia may co-occur with numbness given close anatomical pathways in the sensory thalamus. We aimed to describe the prevalence of dysgeusia and its co-occurrence with numbness in a large population of MRgFUS thalamotomy patients, while also assessing treatment effectiveness for patients experiencing dysgeusia.

Methods: A cohort analysis using MRgFUS data between 2020 to 2023 was performed. Inclusion criteria were unilateral MRgFUS thalamotomy for ET or TdPD with minimum follow-up data of 1 month. Tremor outcomes were assessed using the Clinical Rating Scale for Tremor Part B (CRST-B). Tremor, dysgeusia, and paresthesia were evaluated at baseline, and at 1-, 3-, and 6-months post MRgFUS.

Results: We identified 126 eligible patients. Dysgeusia rates were 21.4% at 1-month, 11.3% at 3-months, and 6.0% at 6-months. Numbness rates were 13.5% at 1-month, 13.9% at 3-months, and 8.3% at 6-months. Patients experiencing dysgeusia were 1.8-times more likely to experience numbness at 1-month (p = 0.185), 3.6-times more likely at 3-months (p = 0.007), and 15.4-times more likely at 6-months (p < 0.001). At all follow up durations, tremor outcomes were significantly improved from baseline, including at 6-months with CRST-B score (mean, SD) of 2.7 ± 3.69, compared with baseline 11.3 ± 4.33 (p < 0.001). There was no significant differences in tremor outcomes between dysgeusia and non-dysgeusia patients at any follow up durations.

Conclusion : Dysgeusia, a side effect of MRgFUS is a predictor of persistent numbness, especially if present at 6 months. Identification of dysgeusia during MRgFUS may help recuded the likelihood of long-term sensory and taste complications. Dysgeusia is not associated with tremor outcomes after MRgFUS.