Acute response of non-motor symptoms to subthalamic deep brain stimulation in Parkinson's disease

Background: Subthalamic deep brain stimulation (STN-DBS) is an established treatment for the motor complications of Parkinson's disease (PD) and may have beneficial effects on non-motor symptoms (NMS). However, the acute effect of STN stimulation on NMS has only been explored in small PD cohorts with short post-surgical follow-up. Objective: To study NMS response to an acute stimulation challenge in an STN-DBS PD population with a medium/long-term post-surgical follow-up. Methods: 32 STN-DBS PD patients were tested twice (MED OFF/STIM OFF and MED OFF/STIM ON). MDS-UPDRS-III, blood pressure (BP) assessment, a visual analogue scale for pain and fatigue and State Trait Anxiety Scale score were evaluated during both stimulation conditions. NMS were assessed with MDS-UPDRS-I, Non-Motor Symptoms Scale, Geriatric Depression Scale and the Neuropsychiatric Inventory scale. Results: Mean (SD) age was 62.5 (+/- 13.3) years, mean disease duration 18.7 (+/- 5.1) years, mean postsurgical follow-up 4.6 (+/- 1.3) years, and the mean reduction of levodopa equivalent daily dose after surgery was 58.9% (+/- 25.4%). Mean (SD) motor response to stimulation was 40% (15%). STN stimulation significantly improved anxiety (mean 18%+/- 19%, P < 0.005) and fatigue (mean 25% 51%; P < 0.05), while pain, although improved did not reach statistical significance. With stimulation ON, BP significantly decreased during orthostatism (P < 0.05) and there was a significant increase in asymptomatic orthostatic hypotension (P < 0.05). Conclusions: Acute STN stimulation improves anxiety and fatigue but decreases orthostatic BP in PD, several years after surgery. These effects should be considered when assessing long-term effect of DBS. (C) 2017 Elsevier Ltd. All rights reserved.