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

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.

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.

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.

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