Event-related desynchronization and Parkinson's disease. Interest of the analysis of movement programming.

This study was aimed at determining the spatiotemporal distribution of even t-related desynchronization (ERD) during self-paced voluntary movement in o rder to establish the interest of this method for the analysis of movement programming in Parkinson's disease. Desynchronization of mu rhythm was reco rded 2 s before to 0.5 s after right then left self-paced voluntary wrist f lexions from II leads covering the primary sensorimotor cortex (central), s upplementary motor area (frontocentral) and parietol cortex (parietocentral ). Recordings Mere obtained from ten control subjects, ten patients treated for Parkinson's disease (bilateral symptoms) and 20 patients presenting wi th right or left hemiparkinsonism before and after chronic administration o f L-dopa. In the control group, ERD started over the contralateral primary sensorimotor cortex 1,750 ms before movement and was bilateral just before performance of the movement. In both treated and de nolo Parkinson's diseas e groups, decrease in ERD latency (1,000 to 1,250 ms before movement) was o nly observed when movements were performed with the akinetic hand and corre sponded to a decrease in motor cortical activity. This confirmed that progr amming of movement is affected in Parkinson's disease. Earlier ERD with cen tral ipsilateral distribution were also observed suggesting that other cort ical areas might be activated to compensate for dysfunction of movement pro gamming and to increase the level of cortical activity required for perform ance of the movement. The administration of L-dopa to de novo hemiparkinson ians patients resulted in increased ERD latency over contralateral and ipsi lateral central areas. As in the treated Parkinson's disease group, frontoc entral ERD could also be recorded. L-dopa would thus partially restore the affected motor programmation and modulate cortical activation in both suppl ementary motor area and primary motor cortex, the latter receiving more aff erences from basal ganglia. (C) 1999 Elsevier, Paris.