Long-term follow up of subthalamic nucleus stimulation in Parkinson's disease.

Twenty-two patients with PD received bilateral implants for high frequency stimulation of the subthalamic nucleus. The patients were treated for more than 1 year (up to 36 months). At the last visit, the Unified Parkinson Disease Rating Scale (UPDRS) motor score without medication improved by 50.2% (p < 0.001) and the UPDRS activities of daily living score improved by 68.4% (p < 0.001). The most common long-lasting adverse events were hypophonia and dysarthria; transient events were increased sexuality and mania. The surgical procedure induced transient intraoperative psychosis in seven patients.