Research has revealed that magnetic resonance (MR)-guided focused ultrasound (MRgFUS) thalamotomy is an effective and safe treatment for essential tremor (ET). Focusing on the ipsilateral-hand and axial tremor subscores, this study aims to examine the efficacy of MRgFUS in ET patients. Researchers evaluated the tremor scores and side effects of 100 patients treated between 2012 and 2018 at 1, 3, and 24 months. Patients with ipsilateral-hand tremors who responded to treatment (defined as patients with more than 30% improvement at any time point) were compared to those who did not. Investigators analyzed the characteristics that predicted success and the correlations between them. Probabilistic weighted maps of enhancements were created. After the first session, axial, contralateral-hand, and total tremor scores decreased significantly from baseline (P<0.0001). Ipsilateral subscores did not show any statistically meaningful improvement. Group-level ipsilateral-hand improvement was observed in a subset of patients (n=20), and this improvement was maintained across all follow-ups (P<0.001). A multivariate analysis found that higher baseline scores were associated with greater ipsilateral-hand and axial tremor improvement. The probabilistic maps showed that the hotspot of the lesion for axial improvement was located more medially than the hotspot for contralateral improvement. Total tremor, axial tremor, and contralateral tremor were greatly reduced after MRgFUS treatment. A consistent group-level treatment effect was seen for ipsilateral-hand tremors in a sample of individuals. A spatial link between lesion location and axial and contralateral improvement was identified, consistent with the somatotopic organization of the ventral intermediate nucleus. However, ipsilateral improvement seemed to be less closely related to lesion location.

Source: jnnp.bmj.com/content/early/2022/08/22/jnnp-2021-328459