The impact of age and disease duration on the long term outcome of neurostimulation of the subthalamic nucleus

Background: Selection of patients with Parkinson's disease for neurostimulation of subthalamic nucleus (STN-DBS) is still poorly studied. Aim: To identify the impact of age and disease duration on the outcome of bilateral STN-DBS. Methods: 110 operated patients in a single center covering a large range of age and disease duration were retrospectively included and followed for up-to 5 years. Standardized UPDRS assessments were obtained at 0.5-1 and 3-5 years. Patients were stratified into three age groups (≤55, 56-64 and ≥65 years) and the middle age group was further stratified into 2 disease duration subgroups (<15years, ≥15 years). Results: The age groups had comparable baseline data except for the predefined differences. Compared to baseline early and late intra-group "Med Off-Stim On" motor scores were significantly improved for all groups (p<0.001). Mood/cognition were significantly improved in younger two groups (p=0.008, 0.019) at 0.5-1 year. Inter-group comparisons showed significantly worse early and late axial scores for older patients (p<0.05). All groups had comparable postoperative improvement except for the older group which had significantly less improvement of early UPDRS-II, late UPDRS-I, and early and late PIGD/axial scores. Different disease durations had no effect on the outcome except for worse Schwab and England Off-score in longer duration group (p=0.02). Side effects of surgery and long-term management were similar. Conclusion: STN-DBS is an efficient treatment of advanced PD for all treated age-groups. Provided strict inclusion criteria are respected, older age and longer disease duration are associated with slightly worse effects mainly on L-dopa-resistant symptoms. © 2013 Elsevier Ltd.