Long-term effect of electrostimulation of the subthalamic nucleus in bradykinetic-rigid Parkinson's disease.

The motor effects of unilateral stimulation of the subthalamic nucleus on hypokinesia were studied in two patients 58 and 52 years old, both modified Hoehn and Yahr 2.5, at 16 and 15 months after the implantation of a quadripolar electrode (Medtronic). Motor UPDRS, time in the pegboard test, walking time, tapping, and serial reaction times were recorded. Chronic unilateral stimulation was associated with reversible improvement of measures of reaction time and hypokinesia > 1 year after the stereotactic electrode implantation. The beneficial effect was mainly contralateral to the stimulation. However, improvement of axial functions was also observed (phonation, walking).