Pallidal deep brain stimulation for the treatment of DYT6 dystonia: a case report and review of literature.

Little is known about the results of pallidal deep brain stimulation (DBS) in DYT6 dystonia. This will be the first report of DYT6 dystonia treated with pallidal DBS from Iran. A 21 years old male patient with DYT6 dystonia underwent bilateral deep brain stimulation. The target of DBS was the sensorimotor region of the posteroventral globus pallidus internus (GPi). DBS parameters included an amplitude of 2.7 V, frequency of 160 Hz, and pulse width of 90 μs which were adjusted according to the patient's response 12 months after surgery. Treatment outcome was measured by the patient's Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) score. Before surgery, the patient's BFMDRS score was 32. However, BFMDRS score reduced to 7 at one year follow up after surgery (78% improvement of total score). Dystonic symptoms of extremities and mouth completely resolved. Also speech and swallowing function significantly improved. Although previous observations reported a poor to moderate response in speech, we found DBS as an effective treatment not only for dystonic features, but also for speech improvement of DYT6 dystonia.