Deep Brain Stimulation for VPS16-Related Dystonia: A Multicenter Study

Abstract

Objective: The objective was to evaluate the effects of deep brain stimulation (DBS) in an international cohort of patients with VPS16-related dystonia. Methods: This observational study collected preoperative and postoperative demographic, clinical, stimulation, genetic, neuroimaging, and neurophysiological data of medically refractory DYT-VPS16 patients with implanted DBS in 10 international centers. Motor symptoms and disability outcomes were assessed using the Burke-Fahn-Marsden Dystonia Rating Scale Motor (BFMDRS-M) and Disability (BFMDRS-D) scales. A cut-off threshold for considering response to DBS was set at 25% of BFMDRS-M improvement at the last follow-up (FU) compared to baseline. Results: The cohort consisted of 26 participants (17 men, 65.4%). Age at dystonia onset and surgery was 17.8 +- 10.9 and 35.3 +- 14.8 years, respectively. At the last FU, 102.5 +- 57.3 months (range, 2-216), the mean BFMDRS-M improvement was 41.6 +- 37.3% (26/26 patients) and 34.8 +- 42.6% for the BFMDRS-D (23/26 patients). Most patients (19/26, 73%) were considered responders. Higher motor improvement was associated with stimulation of the ventroposterior portion of the internal globus pallidus. A significant inverse relationship was observed between improvement in BFMDRS-M at last FU, and the presence of spasticity (p = 0.027) and fixed skeletal deformities (p = 0.001) before surgery. Non-responders had a younger age at disease onset and at implantation, shorter disease duration at DBS surgery, and higher baseline BFMDRS scores. Interpretation: DBS was an effective treatment for three-quarters of patients with pathogenic VPS16 variants in our cohort. Mean motor improvement was most pronounced at the 1-year FU, but persisted at the last FU despite disease progression. ANN NEUROL 2025