High-frequency stimulation of the globus pallidus for the treatment of Parkinson's disease.

Long-term treatment of Parkinson's disease (PD) with levodopa is complicated by the development of motor fluctuations and dyskinesias. Posteroventral pallidotomy can improve tremor, bradykinesia, rigidity, and dyskinesias in PD. We performed chronic stimulation of the globus pallidus (CSGP) to duplicate the positive results of pallidotomy with reduced risk of permanent neurologic deficit in patients with advanced PD. The lead for CSGP was stereotactically implanted with the aid of microelectrode recordings in the globus pallidus pars interna. An electrical pulse generator was implanted in the subclavicular region. Stimulation settings were adjusted by computer. Five PD patients (four men, one woman) with disabling symptoms were enrolled. Three of the patients had bilateral implants. At 3 months following the last implant, four patients rated themselves as markedly improved, and one patient was moderately improved. The amount of time in the "on" state increased from 21% at baseline to 65% at 3-month follow-up (p < 0.05). There was a significant improvement in all subscales of the UPDRS (p < 0.05). One patient had an asymptomatic intracranial bleed, one patient had transient hemiparesis during surgery with stimulation, and one patient required surgical repositioning of the lead. Adverse effects caused by stimulation were minimal. CSGP is a safe and effective procedure in PD patients with motor fluctuations and dyskinesias.