Long-term effects of directional deep brain stimulation in Parkinson’s disease: a randomized clinical trial on motor and non-motor symptoms

Abstract

AbstractBackgroundDeep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson’s disease (PD) that is more precisely focused to the desired target structure may avoid nearby structures that are responsible for undesired side effects.ObjectiveComparing the long-term effects of STN-DBS with segmented or ring contacts on motor and non-motor symptoms in akinetic-rigid PD patients.MethodsThis study was a prospective randomized clinical trial. At 6-months postoperatively, the optimal omnidirectional (OS) and directional (DS) stimulation contacts were compared in MedOFF within a double-blind cross-over design, both acutely (within one day) and chronically, i.e., after 3-week stimulation blocks of each condition. The examination included motor and non-motor evaluations (e.g., cognition, mood and quality of life). Importantly, the stimulation intensity of the optimal DS was adjusted such that the total electrical energy delivered (TEED) was equivalent to the TEED of the optimal OS.ResultsThere were no significant differences between OS and DS with regard to all outcome parameters, with 30% less stimulation intensity of the latter. Notably, OS scored (non-significantly) better than DS in all motor and non-motor measures apart from the cognitive evaluation, where OS led to a deterioration of executive functions. However, in 3 of 19 patients, the stimulation intensity of DS needed to be increased above the TEED-estimated values to reach the motor benefits of OS.ConclusionsReliable comparisons between OS and DS require long-term clinical evaluations. A potential differential influence on motor and non-motor symptoms needs to be investigated in future confirmatory studies.Registration: ClinicalTrials.gov:NCT03548506