Dreaming in Parasomnias: REM Sleep Behavior Disorder as a Model.

REM sleep behavior disorder (RBD) involves the loss of normal muscle paralysis during REM sleep, causing people to act out their dreams. Patients with RBD report high dream recall frequency and vivid, often violent dream content. Isolated RBD (iRBD) is recognized as an early sign of neurodegeneration, often preceding α-synucleinopathies like Parkinson's disease. This narrative review synthesizes evidence on dream activity in RBD, compares it with other non-REM parasomnias, and examines how dream features in RBD associated with α-synucleinopathies might clarify the role of dreams in neurodegenerative processes.

Study at a glance

Abstract

Sleep parasomnias have drawn the interest of sleep experts because they represent a valuable window to directly monitor dream activity and sleep mentation associated with nocturnal events. Indeed, parasomnias and their manifestations are helpful in investigating dream activity and features, overcoming methodological limits that affect dream study. Specifically, REM sleep Behavior Disorder (RBD) is a parasomnia characterized by enacted dream episodes during Rapid Eye Movements (REM) sleep, caused by the loss of physiological atonia. Patients suffering from RBD report a peculiar oneiric activity associated with motor episodes characterized by high Dream Recall Frequency (DRF) and vivid dreams. Additionally, isolated RBD (iRBD) represents a prodromal stage of neurodegeneration preceding the development of α-synucleinopathies. This narrative review aims to combine evidence describing dream activity in RBD and similarities and differences with other NREM parasomnias. Moreover, a special focus has been reserved for those conditions in which RBD is associated with α-synucleinopathies to clarify the potential role of dreams in neurodegenerative processes.