Association of MRI Measurements with Cognitive Outcomes After STN-DBS in Parkinson's Disease.

Objectives: Subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment for improving the motor symptoms of Parkinson's disease (PD). Overall, cognitive function remains stable after STN-DBS in most patients. However, cognitive decline, specifically in the verbal fluency domain, is seen in a subset of STN-DBS patients. Currently, predictors of cognitive decline in PD patients treated with STN-DBS are not well known. Thus, identification of presurgical predictors might provide an important clinical tool for better risk-to-benefit assessment. This study explores whether whole brain white matter lesion (WML) volume, or hippocampal and forebrain volumes, measured quantitatively on MRI, are associated with cognitive changes following STN-DBS in PD patients.

Methods: We conducted a retrospective study using presurgical, and ≥ 6-month postsurgical neuropsychological (NP) evaluation scores from 43 PD patients with STN-DBS. Mean pre/post NP test scores for measures of executive function, attention, verbal fluency, memory, and visuospatial function were analyzed and correlated with WML volume, and brain volumetric data.

Results: Although cognitive measures of verbal fluency, executive function, attention, memory, and visuospatial function showed declines following STN-DBS, we observed limited evidence that white matter lesion burden or cortical atrophy contributed to cognitive change following STN-DBS.

Conclusions: These results suggest that post-STN-DBS cognitive changes may be unrelated to presurgical WML burden and presence of cortical atrophy.