Pre-operative obesity may influence subthalamic stimulation outcome in Parkinson's disease.

Abstract Background Pre-operative predictive factors for optimal post-operative effect of subthalamic nucleus (STN) stimulation in Parkinson's disease (PD) have been previously reported. No study has explicitly assessed the link between excess pre-operative body weight and STN stimulation outcome. Methods We retrospectively compared STN stimulation outcomes of 36 PD patients with excess pre-operative body weight (group 1) and 36 matched normal-weight pre-operative (group 2) PD patients. We focused on the post-operative outcomes in the sub-group of 12 obese (group 3) PD patients. Results The post-operative motor improvement and the reduction of severity of levodopa-related complications were not statistically different between groups 1 and 2 ( P  > 0.05). In the obese group (group 3), the axial sub-score significantly improved by 29.8% in the on -drug/ on -stimulation conditions whereas the improvement was not significant in the off -drug/ on -stimulation condition (22.4%, P  = 0.20). The post-operative Mattis Dementia Rating Score was significantly reduced in group 1 and group 3. Discussion We considered that the post-operative axial impairment observed in the obese PD patients might be essentially consecutive to disease progression and/or post-operative DBS consequences, i.e. surgical procedure or electrical stimulation itself. Moreover, it could be argued that musculoskeletal disorders associated with obesity were responsible for the incomplete efficacy of STN stimulation on axial sub-scores, by increasing gait and balance impairment. Conclusion Pre-operative obesity may be regarded as a predictive clinical factor of axial and cognitive impairment after STN-DBS.