Deep brain stimulation in benign tremulous Parkinsonism

Background: Benign tremulous parkinsonism (BTP) is characterized by prominent resting plus action tremor, mild parkinsonism with limited disability or progression apart from tremor, and a less-robust response to levodopa therapy. This disorder has an uncertain pathophysiologic relationship to idiopathic Parkinson disease. Deep brain stimulation (DBS) should be efficacious for this condition, but there is no previously published experience. Objectives: To assess the clinical outcomes and surgical complications of patientswithBTPwhounderwentDBS. Design: Retrospective case series. Setting: Tertiary care medical center. Patients: Twelve men and 3 women with BTP who underwent DBS for levodopa-refractory tremor. Main Outcome Measures: Tremor status after DBS, preoperative vs postoperative scores on the Fahn-Tolosa- Marin tremor scale, and the presence of adverse events. Results: Of the 15 patients, 8 underwent unilateral thalamic nucleus ventralis intermedius (VIM), 4 bilateral VIM, and 3 bilateral subthalamic nucleus DBS. At last follow-up at a median of 4 years post-DBS, 7 patients were tremor free, 6 had only trace tremor, and 2 were definitely improved but with residual tremor. The median preoperative Fahn-Tolosa-Marin tremor scale score was 17 (range, 11-21); the tremor scale score at the last videotaped follow-up was 1 (range, 0-6). Median time between the 2 videotapes was 11.5 months (range, 3-14 months). No patients experienced adverse events after the surgical procedure. Conclusions: These findings support the efficacy of DBS, with VIM and STN targets, in medically refractory BTP-related tremor. Further studies are needed to explore the long-term durability of response and to better compare the surgical targets.