Subthalamic nucleus stimulation for Parkinson's disease preferentially improves akinesia of proximal arm movements compared to finger movements

Deep brain stimulation of the subthalamic nucleus (STN‐DBS) reduces akinesia in Parkinson's disease but its impact on fine motor functions was unknown. We assessed the effects of DBS and a levodopa (L‐dopa) test on the timing of the precision grip in 18 patients. Improvement on UPDRS‐items reflecting hand functions and the shortening of the first phases of the precision grip were more distinct in the L‐dopa test than in the pure STN‐DBS condition. Other akinesia items and the time for build‐up of lifting force were equally improved in both conditions. This suggests that routine STN‐DBS might not be equally effective on all aspects of fine motor functions. © 2003 Movement Disorder Society