Movement Related Cortical Potentials and L-DOPA in Parkinson 's Disease

Abstract

We recorded movement related cortical potentials (MRCPs) during self-paced, voluntary extension movement of the right wrist in normal subjects and in patients with Parkinson's disease (PD) and assessed premovement components of MRCPs on the midline (Cz), the ipsilateral (C4) and the contrlateral (C3) hand sensorimotor areas. All the patients were in the second stage of Hoebn and Yahr scale and non-demented. Drug therapy of the patients had been stopped for at least 24 hour before recording We measured (1) the latency of the negativity before EMG activity (HP), (2) the amplitude of the MRCPs component at peak negativity just before or after EMG onset (N1), (3) the amplitude of MRCPs component at 650 ms before EMG onset (NY1), (4) the rise in the MRCPs component between the peak N1 and NY1 (NY2). The N1 and NY2 amplitudes weren't different between the normal subjects and the patients. But HP latencies were shorter and NY1 amplitudes were smaller in the patients at all electrode positions. MRCPs were also recorded in the patients when they were on L-DOPA therapy. The abnormal MRCPs components (HP latency and NY1 amplitude) in the patients had been found in normal limits during L-DOPA therapy. It has been suggested that the NY1 component of MRCPs reflects activity supplementary motor area (SMA) Our findings show that SMA activity has been decreased in PD during self-paced, voluntary movement preparation and this activity can be increased by L-DOPA.