Right Brodmann area 18 predicts tremor arrest after Vim radiosurgery: a voxel-based morphometry study.

Area of Science:

• Neurosurgery
• Neurology
• Radiology

Background:

• Drug-resistant essential tremor (ET) often requires stereotactic procedures like deep-brain stimulation or radiofrequency thalamotomy.
• For non-surgical candidates, high-focused ultrasound (HIFU) or radiosurgery (RS) targeting the ventro-intermediate nucleus (Vim) are options.
• The precise mechanisms underlying tremor reduction after Vim RS or HIFU remain unclear.

Purpose of the Study:

• To identify anatomical correlates of tremor arrest following radiosurgery (RS) for essential tremor (ET).
• To assess if pretherapeutic neuroimaging can predict treatment outcomes one year after Vim RS.

Main Methods:

• Voxel-based morphometry (VBM) was used on pre-treatment neuroimaging data from 52 patients with ET undergoing left unilateral Vim RS.
• Gray matter density (GMD) at baseline was statistically analyzed against tremor score improvement one year post-treatment (TSTH).
• A statistical parametric mapping analysis of variance (ANOVA) model incorporated TSTH as a continuous variable.

Main Results:

• A significant correlation was found between higher baseline GMD in the right Brodmann area (BA) 18 (visual association cortex V2) and better TSTH improvement at one year.
• The statistical significance level was p = 0.05 with a cluster size (Kc) of 71.
• No a priori hypothesis guided the statistical model, indicating an exploratory finding.

Conclusions:

• Routine baseline structural neuroimaging, specifically GMD in the right visual association cortex (BA 18), can predict tremor arrest one year after Vim RS.
• This finding suggests a potential link between visual processing areas and tremor control mechanisms.
• Further research is needed to determine if visual areas should be incorporated into targeting strategies for ET treatment.