Impact of deep brain stimulation on cognitive impairment in Parkinson's disease: A retrospective longitudinal study

Subthalamic nucleus deep brain stimulation (STN-DBS) is a well-established treatment for improving motor symptoms, non-motor symptoms, and quality of life (QOL) in patients with advanced Parkinson's disease (PD). However, its effects on patients with cognitive impairment (CI) remain controversial due to the unique challenges and risks posed by cognitive decline. This study aimed to evaluate the mid- to long-term impact of STN-DBS on motor function, non-motor symptoms, and QOL in PD patients with CI. A retrospective cohort of 72 PD patients who underwent STN-DBS and 73 non-DBS patients was analyzed. Baseline and follow-up assessments (minimum one-year follow-up) included motor function (MDS-UPDRS III "off"), non-motor symptoms (NMSS), QOL (PDQ-8), and cognitive function (MMSE). Patients were stratified into a CI cohort based on education-adjusted MMSE cutoffs, with 30 patients in the STN-DBS group and 23 in the non-DBS group. Over two years, the STN-DBS group showed significant improvements in motor function, reduced medication burden (LEDD), and enhanced QOL. Notably, patients with CI in the STN-DBS group achieved better long-term motor and non-motor outcomes compared to the non-DBS group. These results highlight the potential of STN-DBS to offer sustained benefits for cognitively impaired PD patients, though further research is necessary to confirm its long-term safety and efficacy.