Motor Symptom Asymmetry Predicts Cognitive and Neuropsychiatric Profile Following Deep Brain Stimulation of the Subthalamic Nucleus in Parkinson's Disease: a 5-Year Longitudinal Study.

Abstract

Risk factors (e.g., motor symptom asymmetry) for short- and long-term cognitive and neuropsychiatric symptoms following deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients with Parkinson's disease have yet to be fully identified. The objectives of the present study were to determine whether motor symptom asymmetry in Parkinson's disease is one such risk factor and to identify predictors of subnormal cognitive decline. A total of 26 patients receiving STN-DBS (13 with left-sided motor symptoms and 13 with right-sided ones) underwent follow-up neuropsychological, depression and apathy assessments over a 5-year period. Nonparametric intergroup comparisons were performed on raw scores, as well as Cox regression analyses on standardized Mattis Dementia Rating Scale scores. Compared with patients who had predominantly left-sided symptoms, right-sided patients scored higher on both apathy (at 3months and 36months) and depressive symptoms (at 6months and 12months) and scored lower on global cognitive efficiency (at 36months and 60months). Survival analyses revealed that only right-sided patients had subnormal standardized dementia scores, which were negatively associated with the number of perseverations in the Wisconsin Card Scoring Test. Right-sided motor symptoms are a risk factor for more severe short- and long-term cognitive and neuropsychiatric symptoms following STN-DBS, confirming literature findings on left hemispheric vulnerability.