Uneven benefits of subthalamic nucleus deep brain stimulation in Parkinson's disease—A 7-year cross-sectional study

AbstractObjectivesSubthalamic nucleus deep brain stimulation (STN-DBS) for motor symptoms of Parkinson's disease (PD) is promising. However, the benefits of STN-DBS are uneven for the cardinal motor symptoms, as well as for mentality and activities of daily living as the disease progresses. In this report, we will try to clarify which target symptoms have long-term effects during 7 years of STN-DBS.Materials and MethodsFrom February 2002 to February 2011, 120 PD patients who underwent STN-DBS were enrolled in this cross-sectional study. Data analysis was performed at postoperative follow-up periods of 1 year, 2 years, 5 years, and 7 years. The Unified Parkinson's Disease Rating Scale (UPDRS) was evaluated in four combinations of levodopa/DBS, on/off.ResultsWith levodopa off/DBS on, the UPDRS Part III score improved significantly within the 7 years of follow-up (p < 0.001). Decrements in the degree of improvement in axial symptoms were observed after the 5th year. Despite significant improvement in the UPDRS Part II during the 7 years of follow-up, the score of the Schwab and England Activities of Daily Living Scale declined after the 5th year of DBS. With levodopa off/DBS off, the scores for Part III and all subitems deteriorated in comparison with the preoperative levodopa off score after the 5th year of follow-up. Bradykinesia was significantly worse in the 5th and 7th years (p < 0.05 and p < 0.01, respectively) and the axial component was significantly worse in the 7th year (p < 0.05). Stimulation side effects included hypophonia (20.8%), dysarthria (15%), sialorrhea (14.2%), and decreased memory (14.2%). Other surgically related adverse effects included intracranial hemorrhage (3.3%), pulmonary edema (N = 3), deep vein thrombosis (N = 1), seizure (N = 1), depression (N = 7), and mania/hypomania (N = 11). Five electrodes were revised and two devices became infected. DBS stimulation parameters remained stable except for a significant reduction in frequency in the 7th year.ConclusionLong-term effects of DBS on motor disability are promising. DBS showed uneven beneficial effects, and least improvement in axial symptoms and verbal fluency. The disease progressed despite significant positive effects of DBS on the cardinal motor disability symptoms of PD and quality of life at 7 years