Deep brain stimulation of the subthalamic nucleus in Parkinson’s disease after 15 years: Clinical outcome and caregiver burden

Background and objectivesTo provide a detailed overview of motor and non-motor outcome of Parkinson disease (PD) patients with deep brain stimulation (DBS) of the Subthalamic nucleus (STN) 13-17 years after surgery. Little information on long-term follow-up (>10 years) after surgery is available yet, with a high percentage of loss to follow-up (FU).MethodsIn this observational cohort study data on motor, autonomic symptoms, cognitive outcome, mood, quality of life, activities of daily living, Unified Parkinson’s disease rating scale (UPDRS, version 1) scores and dopaminergic medication were collected average 15.1 years (±1.5 standard deviation) after surgery. To limit the loss to FU, patients unable to visit the hospital have been evaluated at their place of residency (e.g. home or nursing home). Furthermore, caregiver burden was assessed.ResultsFifteen (35%) of the 43 included patients survived follow-up, of which 9 patients were assessed at their institution. UPDRS I (1.46 vs. 6.7, p<0.005), UPDRS II (10.5 vs. 30.5, p<0.01) and UPDRS III (47.7 vs. 18.3, p=0.005) significantly worsened compared to baseline with medication. Axial symptoms and bradykinesia were most severely affected of the UPDRS III score. New autonomic symptoms were dominant. One third (n=5) of caregivers reported significant burden. EQ-5D was 0.43 and 4 patients (27%) showed signs of moderate to severe depression. Six patients (40%) met criteria of dementia.ConclusionCognitive, axial, bradykinesia and autonomic symptoms are highly dominant after 15 years of follow-up, whereas tremor and rigidity show no significant worsening over time. This significantly affects health status, quality of life and caregiver burden.