Subthalamic nucleus stimulation applied in the earlier vs. advanced stage of Parkinson's disease - Retrospective evaluation of postoperative independence in pursuing daily activities

While bilateral stimulation of the subthalamic nucleus (STN) has been commonly applied for patients with advanced Parkinson's disease (PD), surgery in the earlier stage of the disease may yield a better prognosis. We retrospectively analyzed the pre- and postoperative activities of daily living (ADL) of 38 PD patients who had undergone bilateral STN stimulation 3 months earlier. Preoperative Unified Parkinson's Disease Rating Scale (UPDRS) scores for neuropsychiatric, axial and ADL impairments were negatively correlated with the postoperative Schwab & England ADL (S-E) scale in the off-medication status (p < 0.01). Patients with longer disease duration had a lower postoperative S-E scale, but their correlation was not statistically significant (p = 0.0467). Age was not a significant predictor of postoperative ADL. Patients with a preoperative on-medication S-E scale ≤60% (n = 14) manifested a greater response rate to surgery than did those with a preoperative S-E scale ≥70% (n = 24). However, patients with poorer preoperative ADL were unable to perform ADL independently after surgery (postoperative S-E was 70.0 ± 12.4% in the on-, and 65.7 ± 16.0% in the off-medication status) and the difference from patients with better preoperative S-E was significant (postoperative S-E 92.5 ± 5.3% in the on-, and 90.4 ± 6.2% in the off-medication status) (p < 0.0001). Our findings suggest that the delivery of STN stimulation earlier in the course of PD may result in greater independence in postoperative ADL.