The role of deep brain stimulation as a surgical treatment for Parkinson's disease.

Patients with advanced Parkinson's disease (PD) frequently suffer disabling motor complications that cannot be satisfactorily controlled with medical therapy. Deep brain stimulation (DBS) has recently been introduced by Benabid and his colleagues in Grenoble, France, as a new surgical procedure for the treatment of PD patients. DBS simulates the effects of a lesion without the need to make a destructive brain lesion. In this procedure, an electrode is implanted in the brain target and connected to a subcutaneous pacemaker. DBS of the ventro-intermediate (Vim) nucleus of the thalamus has been shown to ameliorate tremor in patients with tremor-dominant PD. DBS of the subthalamic nucleus (STN) and globus pallidus pars interna (GPi) have been shown to improve all of the cardinal features of PD and to markedly reduce dyskinesia and motor fluctuations. Adverse events are associated with the surgical procedure, the device, and stimulation, but the procedure is usually well tolerated. On the basis of these findings, the FDA has recently approved unilateral DBS of the Vim for treatment of tremor in PD and is currently considering approval of DBS for STN and GPi. This article reviews existing information with respect to DBS.