Causes of failure of pallidal deep brain stimulation in cases with pre-operative diagnosis of isolated dystonia.

Introduction: Pallidal deep brain stimulation (GPi-DBS) is an effective therapy for isolated dystonia, but 10-20% of patients show improvement below 25-30%. We here investigated causes of insufficient response to GPi-DBS in isolated dystonia in a cross-sectional study.

Methods: Patients with isolated dystonia at time of surgery, and <30% improvement on the Burke-Fahn-Marsden dystonia-rating-scale (BFMDRS) after ≥6 months of continuous GPi-DBS were videotaped ON and OFF stimulation, and history, preoperative videos, brain MRI, medical records, stimulation settings, stimulation system integrity, lead location, and genetic information were obtained and reviewed by an expert panel.

DYT7 gene locus for cervical dystonia on chromosome 18p is questionable.

Background: A locus implicated in autosomal dominant cervical dystonia was assigned to chromosome 18p in 1 large family more than 15 years ago. This locus was designated DYT7. We reanalyzed the family clinically and genetically.