The potential neuromodulatory impact of subthalamic nucleus deep brain stimulation on Parkinson's disease progression

Introduction: STN-DBS has been claimed to change progression symptoms in animal models of PD, but information is lacking about the possible neuromodulatory role of STN-DBS in humans. The aim of this prospective controlled study was to evaluate the long-term impact of STN-DBS on motor disabilities and cognitive impairment in PD patients in comparison to Best-Medical-Therapy (BMT) and Longterm-Post-Operative (POP) groups. Material and methods: Patients were divided into 3 groups: the BMT-group consisted of 20 patients treated only with pharmacotherapy, the DBS-group consisted of 20 PD patients who underwent bilateral STN-DBS (examined pre- and postoperatively) and the POP-group consisted of 14 long-term postoperative patients in median 30 month-time after DBS. UPDRS III scale was measured during 3 visits in 9 +/- 2 months periods (V1, V2, V3) in total-OFF phase. Cognitive assessment was performed during each visit in total-ON phase. Results: The comparable UPDRS III OFF gain was observed in both BMT-group and POP-group evaluations (p < 0.05). UPDRS III OFF results in DBS-group revealed significant UPDRS III OFF increase in Delta V2-V1 assessment (p < 0.05) with no significant UPDRS III OFF alteration in Delta V3-V2 DBS-group evaluation (p > 0.05). Cognitive assessment revealed significant alterations between DBS-group and BMT-group in working memory, executive functions and learning abilities (p < 0.05). Conclusions: The impact of STN-DBS on UPDRS III OFF score and cognitive alterations suggest its neuromodulatory role, mainly during the first 9-18 months after surgery. (C) 2019 Published by Elsevier Ltd.