To identify determinants of post-Deep Brain Stimulation (DBS) cognitive decline in individuals with Parkinson’s Disease (PD). 

Pre- and post- operative neuropsychological assessments identify pre-existing cognitive deficits and determine cognitive outcome amongst PD-DBS patients. Post-operative cognitive decline is not well-defined and contributing factors are not well-understood. Declining performance on LM-Delayed Recall (LMDR) indicates memory loss and cognitive decline in PD.

We retrospectively reviewed PD-DBS patients who completed DBS workup, surgery and 1-year post-operative neuropsychology testing at a single center between 2015-2022.  Reliable Change Indices (RCI) and Z-scores identified individual clinically significant differences in neurocognitive performance from pre- to post- DBS exams [WMS-IV Logical Memory (LM), HVLT-R, WASI-II].  Patients with clinically significant declining performance on LMDR were identified, yielding groups with and without post-operative cognitive decline. Between-group comparisons of disease features (e.g., duration, L-Dopa burden, DBS target), socio-demographic background, presence of imaging abnormalities (pre- and post- DBS), assessment modality (telehealth vs in-office), and cognitive diagnosis (amnestic vs non-amnestic MCI), were made using t-tests, chi square, and regression analyses.

18% of PD-DBS patients declined cognitively after surgery. Despite exploring features at both the group and individual levels, no predictors were found, whereas peri- or post-operative factors may contribute.