Cognitive Changes after Deep Brain Stimulation in Parkinson’s Disease: A Critical Review

Concern about cognitive worsening, especially after subthalamic nucleus (STN) deep brain stimulation (DBS) has been reported in Parkinson’s disease (PD) patients, although it has not been deemed severe enough to discredit DBS as a powerful tool in the armamentarium against PD. We here provide an in-depth and critical review of the current literature on this topic, summarizing the available data on the impact of STN and globus pallidus interna (GPi) DBS on each of the following cognitive domains: language, executive function, attention and concentration, memory, visual function, psychomotor and processing speed, and global cognition; then looking in more details into controlled studies as well as studies directly comparing GPi and STN DBS. We conclude that worsening of one or more cognitive function is rare and subtle after DBS in PD patients, without negative impact on quality of life, and that there is very little data supporting that STN DBS has a worse cognitive outcome than Gpi DBS.