Effects of bilateral pallidal or subthalamic stimulation on gait in advanced Parkinson's disease

Bilateral high-frequency stimulation of the internal globes pallidus (GPi) and the subthalamic nucleus (STN) both alleviate akinesia, rigidity, and tr emor in idiopathic Parkinson's disease. To test the specific effect of thes e procedures on gait, we used quantitative gait analysis in addition to rel evant subscores of the Unified Parkinson's Disease Rating Scale in a group of 10 patients with advanced Parkinson's disease treated by GPi stimulation and eight patients treated by STN stimulation. Patients were assessed befo re and 3 months after surgery. Thirty age-matched healthy subjects served a s controls. The non-random selection allowed a descriptive but no direct st atistical comparison of the respective procedure. Gait analysis showed sign ificant stimulation-induced improvements of spatiotemporal gait and step pa rameters in both patient group. Moreover, the effects on step length and ca dence suggested a differential effect of both basal ganglia targets. Hence, the increase in gait velocity in the STN group was almost exclusively due to a significant increase in step length, while in the GPi group statistica lly non-significant increases in both step length and cadence contributed. (C) 2001 Movement Disorder Society.