ABSTRACT
BACKGROUND: Neuroimaging studies suggest an association between apathy after deep brain stimulation (DBS) and stimulation of the ventral part of the subthalamic nucleus (STN) due to the associative fibers connected to the non-motor limbic circuits that are involved in emotion regulation and motivation. We have previously described three patients with severe apathy that could be fully treated after switching stimulation from a ventral electrode contact point to a more dorsal contact point. OBJECTIVES: To determine whether more dorsal stimulation of the STN decreases apathy compared to standard care in a multicenter randomized controlled trial with a crossover design. METHODS: We will include 26 patients with a Starkstein Apathy Scale (SAS) score of 14 or more after subthalamic nucleus (STN) deep brain stimulation (DBS) for refractory Parkinson's disease. This is a multicenter trial conducted in two teaching hospitals and one university medical center in the Netherlands after at least 3 months of STN DBS. Our intervention will consist of 1 month of unilateral dorsal STN stimulation compared to treatment as usual. The primary outcome is a change in SAS score following 1 month of DBS on the original contact compared to the SAS score following 1 month of DBS on the more dorsal contact. Secondary outcomes are symptom changes on the Movement Disorders Society-Unified Parkinson's Disease Rating Scale motor part III, Montgomery-Åsberg Depression Rating Scale, 39-item Parkinson's disease questionnaire, Parkinson's disease impulsive-compulsive disorders questionnaire, changes in levodopa-equivalent daily dosage, apathy rated by the caregiver, and burden and quality of life of the caregiver. TRIAL REGISTRATION: ClinicalTrials.gov NL8279. Registered on January 10, 2020.
Subject(s)
Apathy , Deep Brain Stimulation , Parkinson Disease , Subthalamic Nucleus , Humans , Parkinson Disease/therapy , Parkinson Disease/psychology , Cross-Over Studies , Deep Brain Stimulation/adverse effects , Deep Brain Stimulation/methods , Quality of Life , Treatment Outcome , Randomized Controlled Trials as Topic , Multicenter Studies as TopicABSTRACT
BACKGROUND: Apathy is reported after subthalamic nucleus deep brain stimulation (STN DBS) and associated with a decreased quality of life in Parkinson's disease (PD) patients. Recent studies hypothesized that the location of active DBS contact point relative to the STN subdivisions (motor, associative and limbic) could be related to an increase of apathy. METHODS: 22 PD-patients that underwent STN DBS between January 2019 and February 2020 were divided in an apathy and non-apathy group using the change in the Starkstein Apathy Scale (SAS) after six months of DBS. For both groups the location of DBS electrodes was determined based on 7T MRI subthalamic network analysis, enabling visualization of the subdivisions and their projections relative to the active contact point. MDS-UPDRS III scores were included to evaluate DBS effect. RESULTS: In six patients a post-DBS increase in apathy score was assessed, versus 16 non-apathy patients. Network analysis showed that active contacts in apathy patients were more often positioned in or close to the area within the STN with high density of surrounding projections to associative cortex areas than in non-apathy patients; 63% apathy versus 42% (P = 0.02). The density of surrounding motor projections was lower in the group with increased apathy (18%) than in the group without increased apathy (38%, P = 0.01). Motor UPDRS improvement for the apathy group was 39% and for the non-apathy group 58% (n.s.) CONCLUSION: This new approach in patient-specific subthalamic 7T MRI network analysis visualized an anatomical connectivity substrate for apathy in DBS, with active electrode contacts predominantly in the associative STN.
