Abnormal pattern of cortical activation associated with voluntary movementin obsessive-compulsive disorder: An EEG study

Objective: Converging evidence in patients with obsessive-compulsive disord er (OCD) shows abnormalities of prefrontal areas and basal ganglia, which a re also involved in motor control. Event-related desynchronization of mu an d beta EEG rhythms is considered a correlate of motor activation during mot or preparation and execution, followed by cortical idling or inhibition ind icated by event-related synchronization. The authors investigated the circu its involved in motor behavior in OCD by using event-related desynchronizat ion/synchronization. Method: Data on alpha and beta event-related desynchronization/synchronizat ion with self-paced movement of the right thumb were obtained by using 29-c hannel EEG in 10 untreated OCD patients and 10 normal subjects. Results: OCD patients showed delayed onset of mu event-related desynchroniz ation with movement preparation and less postmovement beta synchronization, compared to normal subjects. Conclusions: Delayed event-related desynchronization in OCD is consistent w ith involvement of structures related to motor programming, such as basal g anglia. Lower levels of postmovement beta synchronization suggest impairmen t of the inhibitory system in OCD.