Chronic anterior pallidal stimulation for Parkinson's disease.

We present the case of a 51-year-old female who had a four-year history of Parkinson's disease with severe "on-off' and disabling progression of symptoms on chronic levodopa therapy. After obtaining FDA approval, we implanted a Medtronic deep brain stimulation lead stereotactically into the right anterior pallidum contralateral to her most symptomatologic side. Intra-operative stimulation trials at 100 Hz caused reproducible reversal of akinetic symptoms and simultaneous microelectrode recording of the posteroventral pallidum revealed decreased neural activity during anterior pallidal stimulation. The patient was evaluated pre-operatively and postoperatively using the Hoehn and Yahr Staging Scale, the Unified Parkinson's Disease Rating Scale (UPDRS), videotape, and a computerized data glove. Six months after implantation, the total UPDRS score was decreased from 68 to 8 and Hoehn and Yahr Staging improved from 3.0 to 1.5 during periods of chronic high frequency stimulation. Dramatic improvements in tremor, dystonia, bradykinesia, and akinesia were noted within seconds of stimulator activation and were also objectively measured using a computerized data glove. This case reveals the potential for therapeutic pallidal stimulation for Parkinson's akinetic symptomatology.