Impact of Preoperative Cognition on Motor Improvement in Bilateral Subthalamic Nucleus-Deep Brain Stimulation for Parkinson's Disease.

OBJECTIVE

This study aimed to assess the influence of preoperative cognition on postoperative motor and nonmotor outcomes in patients with Parkinson disease (PD) after deep brain stimulation (DBS).

MATERIALS AND METHODS

A retrospective study was performed in subjects with PD with bilateral subthalamic DBS. Preoperative cognition was indexed by Parkinson's Disease-Cognitive Rating Scale (PD-CRS) and global neuropsychological evaluation (NPE) scores. The primary outcome was change from baseline to postoperative off-drug Movement Disorders Society Unified Parkinson Disease Rating Scale (MDS-UPDRS) part 3 score. Secondary outcomes included change from baseline to postoperative MDS-UPDRS part 1 subscores.

RESULTS

The study included 226 subjects; 176 patients (77.9%) had normal cognition (PD-NC); 48 (21.2%) had mild cognitive impairment (MCI), and two (0.9%) had PD dementia. Proportional change (-41.4% vs -52.2%, p = 0.013) in off-drug MDS-UPDRS part 3 score was smaller in PD-MCI than in PD-NC. PD-CRS (Pearson's r = 0.236, p < 0.001) and NPE (Pearson's r = 0.219, p < 0.001) scores displayed a positive correlation with proportional change in off-drug MDS-UPDRS part 3 score. Worse PD-CRS scores were related to larger improvements in MDS-UPDRS part 1.2 (hallucinations) (Pearson's r = 0.135, p = 0.045).

CONCLUSIONS

DBS induces a clinically meaningful motor improvement in patients with cognitive impairment and PD, but the improvement may be smaller than in patients who are not cognitively affected. Further research into the risk-benefit balance of DBS in people with PD and cognitive dysfunction is warranted.