Mixed results for GPi-DBS in the treatment of cranio-facial and cranio-cervical dystonia symptoms

The aim of the study is to determine clinical outcomes in patients undergoing Globus Pallidus Internus Deep Brain Stimulation (GPi-DBS) for cranio-facial and cranio-cervical dystonia (Meige) symptoms. A total of 6 patients seen between 2002 and 2010 with cranio-facial and cranio-cervical dystonia symptoms were identified from the University of Florida Institutional Review Board approved database. Patients were videotaped using a standardized protocol, and tapes were randomized and blindly reviewed by a movement disorders neurologist. The Unified Dystonia Rating Scale improved 31.6 ± 23.2% (range: 3.4–63.2%) at 6 months and 63.7 ± 35.3% (range: 6.3–100%) at 12 months. The Burke–Fahn–Marsden Dystonia Rating Scale improved 45.3 ± 29.5% (range: 4.7–75.0%) at 6 months and 61.8 ± 30.9% (range: 16.6–100%) at 12 months. One patient significantly had a very large improvement with little evidence of residual dystonia. Blepharospasm improved in all patients, whereas speech and swallowing did not improve in this cohort. Two patients improved with unilateral GPi-DBS, although one required a contralateral DBS later in the disease course. Two patients were managed with low frequency stimulation (<100 Hz). Two patients had less than 20% benefit. GPi-DBS for cranio-facial and cranio-cervical symptoms is an effective strategy to manage a subset of patients who remain unresponsive to optimized medical management. Unilateral stimulation may be an option for some patients, but it remains unclear whether response to single-sided stimulation will be sustainable. The mixed results of this GPi-DBS case series highlight the need for a careful re-examination of selection criteria, alternative brain targets, and possibly rescue leads for patients who are non-responders to the GPi target.