Sixty hertz pallidal deep brain stimulation for primary torsion dystonia

Abstract

<b>Objective: </b> To evaluate the safety and efficacy of 60 Hz deep brain stimulation (DBS) of the globus pallidus internus (GPi) in 15 consecutive patients with primary dystonia. <b>Methods: </b> We conducted a retrospective analysis of clinic charts relative to 15 consecutive patients with medically refractory primary dystonia who underwent stereotactic implantation of DBS leads within the GPi. Twelve had the <i>DYT1</i> gene mutation. Frame-based MRI and intraoperative microelectrode recording were employed for targeting. All patients were treated exclusively with stimulation at 60 Hz from therapy outset. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) served as the primary measure of symptom severity at baseline and 1, 3, 6, and 12 months after treatment. <b>Results: </b> All patients tolerated DBS treatment well and showed a progressive median improvement of their BFMDRS motor subscores from 38% at 1 month to 89% at 1 year (<i>p</i> &lt; 0.001, Wilcoxon rank sum test). The disability subscores were similarly improved. The clinical response to DBS allowed seven patients to completely discontinue their medications; six additional patients had reduced their medications by at least 50%. Surgical complications were limited to two superficial infections, which were treated successfully. <b>Conclusions: </b> Stimulation of the internal globus pallidus at 60 Hz is safe and effective for treating medically refractory primary dystonia.