Cognitive Decline Following Deep Brain Stimulation

Deep brain stimulation (DBS) targeting the subthalamic nucleus (STN) is a well-established surgical intervention to treat Parkinson's Disease (PD) patients with disabling motor fluctuations and dyskinesias. Although this therapy is effective for motor complications, a subset of patients will go on to experience cognitive decline, which can overshadow improvements in the quality of life provided by STN-DBS. This accelerated decline in cognition occurs in patients despite rigorous evaluation of their neuropsychological status prior to surgery. While the factors contributing to cognitive decline following DBS remain unclear, there is evidence this may be the result of 1) limited cognitive reserve prior to DBS surgery, 2) stimulation that interferes with cognitive networks, and/or 3) a microlesion effect due to placement of the lead. Understanding how these factors contribute to DBS-induced cognitive decline has the potential to improve patient selection for surgery and optimize the selection of stimulation targets that minimize undesirable cognitive side effects.