Neurophysiological changes after cognitive-motor tasks in Parkinson's disease patients with deep brain stimulation.

Chronic deep brain stimulation (CDBS) is a surgical treatment that reduces the cardinal signs of Parkinson's disease (PD). Although CDBS has been in use for a long time, very little has been reported on its supposed effects on cognition, particularly in relation to implants in the subthalamic nucleus. The results of the rare studies that do exist are controversial, and in many cases the studies have several design flaws.