Kinematic effects of subthalamic stimulation on reach-to-grasp movements in Parkinson's disease.

Background: Parkinsonian patients demonstrate particular difficulties when performing sequential motor tasks compared to simple movements indicating an important role of the basal ganglia in switching between different motor programs.

Objective: To investigate the impact of subthalamic stimulation on the kinematics of composed reach-to-grasp movements and on isolated movement segments.

Methods: 11 age matched controls and 16 PD patients with subthalamic stimulation were examined without medication with stimulation switched on and off.