Rapid eye movement sleep behavior disorder: a window on the emotional world of Parkinson disease.

Abstract

REM sleep behavior disorder (RBD) is a parasomnia characterized by motor activity during sleep with dream mentation. Aggressiveness has been considered a peculiar feature of dreams associated with RBD, despite normal score in aggressiveness scales during wakefulness. We aimed to measure daytime aggressiveness and analyze dream contents in a population of patients with Parkinson disease (PD) with and without RBD. This is a single-center prospective observational study; it concerns the description of the clinical features of a medical disorder in a case series. The study was performed in the Department of Neurosciences of the Catholic University in Rome, Italy. Three groups of subjects were enrolled: patients with PD plus RBD, patients with PD without RBD, and healthy controls. The diagnosis of RBD was determined clinically and confirmed by means of overnight, laboratory-based video-polysomnography. For the evaluation of diurnal aggressiveness, the Buss-Perry Aggression Questionnaire (BPAQ) was used. The content of dreams was evaluated by means of the methods of Hall and Van De Castle. Patients with PD without RBD displayed higher levels of anger, and verbal and physical aggressiveness than patients with PD and RBD and controls. Patients with PD and RBD and controls did not differ in hostility. It can be hypothesized that a noradrenergic impairment at the level of the locus coeruleus could, at the same time, explain the presence of RBD, as well as the reduction of diurnal aggressiveness. This finding also suggests a role for REM sleep in regulating homeostasis of emotional brain function.