HIGH-FREQUENCY UNILATERAL THALAMIC-STIMULATION IN THE TREATMENT OF ESSENTIAL AND PARKINSONIAN TREMOR

Pharmacologic treatment for essential tremor and the tremor of Parkins on's disease is often inadequate. Stereotaxic surgery, such as thalamo tomy, can effectively reduce tremors. We performed a multicenter trial of unilateral high-frequency stimulation of the ventral intermedius n ucleus of the thalamus in 29 patients with essential tremor and 24 pat ients with Parkinson's disease, using a blinded assessment at 3 months after surgery to compare clinical rating of tremor with stimulation O N with stimulation OFF and baseline and a I-year follow-up. SLP patien ts were not implanted because of lack of intraoperative tremor suppres sion (2 patients), hemorrhage (2 patients), withdrawal of consent (1 p atient), and persistent microthalamotomy effect (1 patient), A signifi cant reduction in both essential and parkinsonian tremor occurred cont ralaterally with stimulation, Patients reported a significant reductio n in disability, Measures of function were significantly improved in p atients with essential tremor. Complications related to surgery in imp lanted patients were few. Stimulation was commonly associated with tra nsient paresthesias. Other adverse effects were mild and well tolerate d. Efficacy was not reduced at 1) ear. Chronic high-frequency stimulat ion is safe and highly effective in ameliorating essential and parkins onian tremor.