Bidirectional Interplay between Deep Brain Stimulation and Cognition in Parkinson's Disease: A Systematic Review.

ABSTRACT

BACKGROUND: Deep brain stimulation (DBS) is efficacious for treating motor symptoms in Parkinson's disease (PD). OBJECTIVES: The aim is to evaluate the evidence regarding DBS effectiveness after postoperative cognitive deterioration, the impact of preoperative cognition on DBS effectiveness, and the impact of DBS on cognition. METHODS: Literature searches were performed on MEDLINE, EMBASE, and CENTRAL (Cochrane library). Primary outcomes were OFF-drug Unified Parkinson Disease Rating Scale Part III score and cognitive test scores. RESULTS: DBS effectiveness did not differ in patients with postoperative declining compared to stable cognition (n = 5 studies). Preoperative cognition did not influence DBS effectiveness (n = 1 study). DBS moderately decreased verbal fluency compared to the best medical treatment (n = 24 studies), which may be transient. CONCLUSION: DBS motor effectiveness in PD does not appear to be influenced by cognition. DBS in PD seems cognitively safe, except for a moderate decline in verbal fluency. Further research is warranted. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.