Deep brain stimulation for Parkinson’s disease: Cognitive outcome three years after surgery and the relation between preoperative cognitive status, functional health and quality of life after surgery

Background: Effects on non-motor symptoms, for example cognitive side effects, could influence the decision for either globus pallidus pars interna (GPi) or subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson’s disease (PD). Additionally, studies investigating preoperative cognition in relation to functional health (FH) and quality of life (QoL) after surgery have reported contrasting results.