Motor programming is more affected in progressive supranuclear palsy than in Parkinson's disease: A spatiotemporal study of event-related desynchronization

To determine the benefit of motor programming analysis for distinguishing p atients with parkinsonism, we compared the spatiotemporal pattern of event- related desynchronization (ERD) preceding a self-paced voluntary wrist flex ion between two,groups of 10 patients with progressive supranuclear palsy ( PSP) and Parkinson's disease (PD) and 10 control subjects. ERD of the mu rh ythm was computed from 11 source derivations covering the medial frontocent ral, central, and parietocentral areas during two successive left and right experimental conditions (80 self-paced wrist flexions). ERD began in the c ontrol group 1750 ms before movement onset over the contralateral central a rea and then appeared bilaterally on movement execution. In both patient gr oups, spatiotemporal distribution differed from that in the control group. In the PSP group, ERD had a shorter latency over the contralateral primary sensorimotor area compared with the PD group (PSP: 375 ms before movement o nset for both conditions; PD: right flexion 1125 ms before movement onset, left flexion 1000 ms). ERD was observed over the parietocentral area in bot h groups but also with a clear reduction of latency before movement onset i n the PSP group. In both groups, a bilateral central pattern appeared 250 m s before movement execution. In conclusion, our study indicates that ERD an alysis is a useful method for observing the changes in cortical activation and for measuring motor programming impairment in parkinsonism, which was m ore affected in PSP than in PD.