Protocol of a randomized controlled trial investigating Deep Brain Stimulation for MOtor symptoms in patients with Parkinson’s disease DEmentia (DBS-MODE)

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an established treatment for disabling motor symptoms of Parkinson’s disease (PD) that persist despite optimal pharmacological treatment. Currently, DBS is not performed if there is concomitant significant cognitive impairment based on concerns of cognitive deterioration, higher complication rate and less functional improvement. However, this has not been investigated so far. METHODS: A single center, prospective, randomized, open-label, blinded end-point (PROBE design) pilot clinical trial is being performed. Patients are eligible for the trial if they have PD dementia (PDD), are able to provide informed consent, and experience disabling motor response fluctuations, bradykinesia, dyskinesia, or painful dystonia, despite optimal pharmacological treatment. In total 44 patients will be randomized to either STN-DBS accompanied by best medical treatment (DBS group) or to best medical treatment alone (BMT group). The primary outcome measure is the change from baseline to 30 weeks on the Movement Disorder Society—Unified Parkinson’s Disease Rating Scale part III score in a standardized off-drug phase. The main secondary outcome measures consist of scales assessing cognitive aspects of daily living, neuropsychiatric symptoms and impulsive compulsive disorders. Additional secondary outcome measures include motor signs during on-drug phase, dyskinesia, motor fluctuations, cognitive performance, (severe) adverse events, treatment satisfaction, and caregiver burden. Patients will be followed during 52 weeks after randomization. DISCUSSION: The Deep Brain Stimulation for MOtor symptoms in patients with Parkinson’s disease DEmentia (DBS-MODE) trial directly compares the effectiveness and safety of DBS with BMT in patients with PDD. TRIAL REGISTRATION: The DBS-MODE trial has been registered in the International Clinical Trial Registry Platform (NL9361) on the 24(th) of March 2021 (https://trialsearch.who.int/Trial2.aspx?TrialID=NL9361). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12883-023-03142-5.