Exploration of the Reward System by Functional MRI in Parkinson's Disease Patients With and Without REM Sleep Behavior Disorder

Overview

Up to 60% of Parkinson's Disease (PD) patients suffer from REM sleep behavior disorder (RBD), a parasomnia. This disorder is thought to be related to a dysfunction of limbic system and brainstem. Impulse control disorders (ICD) are found in about 14% of PD patients taking dopaminergic drugs. These disorders are thought to be related to a dysfunction of meso-cortico-limbic pathways which belong to the so-called "reward system". A strong link was found between these two disorders and therefore the investigators believe that RBD is associated with impaired reward system. The main objective of this study is to evaluate differences in brain activation between PD patients with and without RBD. The investigators hypothesize that PD patients with RBD have a more severe dysfunction of the reward system (hypoactivation of the meso-cortico-limbic pathway) than patients without RBD, explaining their susceptibility to ICD when exposed to high doses of dopaminergic treatment.

Type of study: Prospective, case control study. Number of centers: 2 (Clermont-Ferrand and Vichy) Patients : The study will be performed in 75 subjects (25 PD patients with RBD, 25 PD patients without RBD and 25 healthy volunteers, age-and sex-matched without any contraindications to perform an MRI) Study Performance : During the first visit (J0, inclusion visit, 3 hours), each subject will perform a clinical and neurological examination (MDS-Unified Parkinson Disease Rating scale (MDS-UPDRS)) and neuropsychological assessment (depression by the Beck Depression Inventory (BDI); apathy by the Lille Apathy Rating Scale (LARS), impulsivity by the Urgency, lack of Premeditation, lack of Perseverance, Sensation Seeking scale (UPPS)) Eligible patients will be welcomed in a subsequent visit at the MRI department for the functional MRI (J0+1week, 1 hour). This session will be of about 45 minutes. The reward system was explored using an experimental task during functional Magnetic Resonance Imaging (fMRI). The name of this task is the"monetary incentive delay task".