Postmovement beta synchronization in patients with Parkinson's disease.

Event-related synchronization (ERS) after self-paced, voluntary brisk movement of the right and left thumb was studied in 17 patients with Parkinson's disease (PD) and 17 age-matched control subjects. All patients were receiving L-DOPA and/or DOPA-agonists. The movement-offset-triggered EEG data were analyzed in the 12- to 16-Hz, 16- to 20-Hz, and 20- to 24-Hz bands for eight time intervals after termination of movement. Significant differences in postmovement beta synchronization were observed in all three frequency bands. As compared with the control group, patients with PD showed a remarkably smaller beta ERS. This was the overall main effect for groups, as well as for interactions concerning side of movement and electrode positions. If beta ERS is a measure of recovery of the primary motor area after movement, our results indicate that this ability is impaired in PD patients.