Altered premotor cortical oscillations during repetitive movement in persons with Parkinson's disease.

Premotor areas play a critical role in the control of repetitive movements. While research has shown that movement-related oscillations are abnormal during repetitive movements in persons with Parkinson's disease (PD), there is limited research examining the contribution of premotor areas, such as the contralateral dorsal premotor area (PMd) and supplementary motor area (SMA), to this impairment. This study compared movement-related oscillations over premotor regions between participants with PD and control participants. Nine participants with PD off and on medication and nine matched control participants were studied. Participants performed cued index finger movements. Spectral power was derived from electroencephalographic recordings from electrodes FC3/FC4 and Cz over the regions of the contralateral PMd and SMA respectively. Movement-related alpha and beta band oscillations were suppressed over electrode FC3/FC4 (contralateral PMd) in participants with PD, particularly at higher movement rates, in both the off and on medication conditions compared to control subjects. The pattern of movement-related oscillations recorded from Cz (SMA) was similar between PD and control groups. This would suggest that the region of the contralateral PMd may be preferentially involved with the control of externally cued repetitive movements and that changes in this activity may contribute to the deterioration of repetitive finger movements at higher rates in persons with PD.