The effect of subthalamic nucleus deep brain stimulation on precision grip abnormalities in Parkinson's disease.

We have studied grip force performance in a group of 10 patients who were in a stable state after implantation of bilateral stimulating electrodes in the subthalamic nuclei (Stn) to counter drug-resistant or drug-induced symptoms of advanced Parkinson's disease. The patients were required to use a precision grip to lift an object which recorded grip force development and lift dynamics. Lifting was performed with stimulation on and with stimulation off under optimal medication.

Grip force abnormalities in de novo Parkinson's disease.

In recent years it has been shown that a variety of movement disorders are associated with abnormalities of the fine motor control of the hand. In Parkinson's disease (PD), these changes consist of a slowing of the rate of grip force development and the use of abnormally large grip forces both during lifting and static holding of an object. It has been suggested, however, that these changes are a direct effect of the patient's levodopa medication or associated with levodopa induced dyskinesias.