Deep brain stimulation for severe dystonia associated with Wilson disease: A prospective multicenter meta‐analysis of an N‐of‐1 trial

Abstract

Background and purposeDisabling dystonia despite optimal medical treatment is common in Wilson disease (WD). No controlled study has evaluated the effect of deep brain stimulation (DBS) on dystonia related to WD. This study was undertaken to evaluate the efficacy of DBS on dystonia related to WD.MethodsA meta‐analysis of an N‐of‐1 prospective, randomized, double‐blind, multicenter DBS study was conducted at two French WD reference centers. Main inclusion criteria were patients with WD, stabilized for at least 6 months with significant disability due to dystonia despite optimized medical treatment. The subthalamic nucleus (STN) was targeted for bradykinetic patients with tonic dystonia, and the internal globus pallidus (GPi) was chosen for patients with hyperkinetic dystonia. Each patient underwent two periods of DBS “on” and two periods of DBS “off,” each lasting 4 months. The order of stimulation conditions was randomized. The primary outcome was the change in the Canadian Occupational Performance Measure Performance (COPM‐P) and Satisfaction scores after each 4‐month period. Secondary outcomes were changes in the Burke–Fahn–Marsden Dystonia Rating Scale (BFMDRS) severity and disability scores and Unified Wilson's Disease Rating Scale (UWDRS) scores.ResultsBetween 12 May 2016 and 7 October 2022, three patients were included. Two patients received bilateral GPi DBS, and one received bilateral STN DBS. There was no change of COPM‐P (p = 0.956), BFMDRS, and UWDRS scores. No serious adverse events were reported.ConclusionsSTN or GPi DBS are ineffective on dystonia related to WD.