Association between subthalamic nucleus volume and outcomes one year after bilateral subthalamic nucleus deep brain...

Deep brain stimulation (DBS) is an effective adjunctive therapy for Parkinson's disease (PD), but there are few biomarkers for the prediction of treatment response. Here, we aimed to evaluate whether subthalamic nucleus (STN) volume could serve as a biomarker for predicting treatment response to STN DBS in PD.

This was a retrospective study of patients who underwent bilateral STN DBS for PD between 2008 and 2021 at our center. Preoperative T2-weighted MRI scans were used to quantify STN volumes, while outcomes were evaluated using both the Hoehn and Yahr scale and Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) total and subcomponent scores at one-year follow-up. Univariate and multivariate linear regression analysis were applied to examine potential relationships between STN volume and clinical outcomes.

Of 94 PD patients treated with DBS, 32 met the inclusion criteria for analysis. Our analysis revealed no significant association between STN volume and motor symptom improvement, as assessed by one-year changes in MDS-UPDRS Parts II (β=0.04; 95 % CI=-0.12-0.20; p = 0.590), III (β=0.07; 95 % CI=-0.35-0.48; p = 0.753), IV (β=-0.02; 95 % CI=-0.07-0.03; p = 0.430), and Hoehn and Yahr scale (β=0.01; 95 % CI=0.00-0.01; p = 0.136. Similarly, STN volume showed no association with MDS-UPDRS Part I total score (β=0.12; 95 % CI=-0.02-0.26; p = 0.096) for non-motor symptoms. However, we identified significant positive associations between STN volume and specific non-motor components, including the "anxious mood" (β=0.02; 95 % CI=0.00-0.04; p = 0.031) and the "pain and other sensation" (β=0.02; 95 % CI=0.00-0.04; p = 0.022) components, though these associations were not significant after adjusting for potential confounders.

In our cohort of patients who underwent bilateral STN DBS for PD, exploratory analyses revealed that larger STN volumes were significantly associated with an increased risk of developing affective symptoms approximately one year postoperatively. No significant association was observed between STN volume and improvement in motor outcomes. Further validation studies are warranted to corroborate the findings from this exploratory analysis.