Rapid Eye Movement Sleep Behavior Disorder

Abstract

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by repeated episodes of dream enactment behavior and REM sleep without atonia (RSWA) during polysomnography. RSWA is characterized by increased phasic or tonic muscle activity seen on polysomnographic electromyogram channels. RSWA is a requisite diagnostic feature of RBD, but may also be seen in patients without clinical symptoms or signs of dream enactment as an incidental finding in neurologically normal individuals, especially in patients receiving antidepressant therapy. RBD may be idiopathic or symptomatic. Patients with idiopathic RBD often later develop other neurological features including parkinsonism, orthostatic hypotension, anosmia, or cognitive impairment. RSWA without clinical dream eneactment, as well as clinically overt RBD, also often occurs concomitantly with synucleinopathy neurodegenerative disorders, which include idiopathic Parkinson disease, Lewy body dementia, and multiple system atrophy. This chapter reviews the epidemiology of RBD, clinical, and polysomnographic diagnostic standards for both RBD and RSWA, previously reported associations of RSWA and RBD with neurodegenerative disorders and other potential causes, pathophysiology of brain structures and networks mediating dysregulation of REM sleep muscle atonia and clinical dream enactment, and considerations for the effective and safe management of RBD.