Deep brain stimulation of the subthalamic nucleus in Parkinson's disease.

OBJECTIVE: To evaluate the clinical effects of subthalamic nucleus deep brain stimulation in patients with Parkinson's disease within the first 12 months after surgery. METHODS: We performed a prospective study in 8 patients with Parkinson's disease, in whom electrodes were implanted in the subthalamic nucleus bilaterally. We compared levodopa-equivalents and the scores of the Unified Parkinson's Disease Rating Scale pre- and post-operatively. The post-operative evaluation was done between 3 and 12 months after surgery. RESULTS: Antiparkinsonian medications were reduced post-operatively by a mean of 61.5% (P < 0.01) from a levodopa-equivalent dosage of 1144.9 +/- 572.5 mg/day to 440.9 +/- 172.1 mg/day. Motor scores improved 44.4% (P < 0.01) and activities of daily living scores 38.2% (P < 0.01). Adverse events included a subcutaneous hematoma in 1 patient after internal pulse generator implantation necessitating evacuation. CONCLUSIONS: Bilateral stimulation of the subthalamic nucleus is associated with significant improvement in motor function and reduction of antiparkinsonian medications in patients with Parkinson's disease in the first 12 months after surgery. On-state dyskinesias were greatly reduced, probably due to the reduction of total antiparkinsonian medications. The procedure is well tolerated.