**1. Introduction**

There are a variety of disorders that can manifest complex movements and behaviors that happen during sleep. REM behavior disorder (RBD) is one such disorder characterized by loss of physiologic REM muscle atonia and dream enactment. Motor activity consists of highly complex, vigorous or violent dream enacting behaviors that are noticed when they result in injuries of the patient or their bed partner. Some behaviors include punching, kicking, jumping out of bed, and talking. If the patient is awoken they may recall an unpleasant dream of falling, being attacked or chased by either another person or an animal. The latter are common dream contents associated with RBD.

A disorder of the elderly, RBD onset occurs between the sixth and seventh decades [1], with an estimated prevalence of between 1 and 7.7% of the population [2]. The true extent of this disorder is largely unknown [3]. The disease is male predominant [4]. Symptoms are thought to arise from underlying dysfunction of the brainstem structures that regulate REM sleep atonia, mostly located in the dorsal mesopontine tegmentum and ventromedial medulla [4]. Injury to these areas can occur in the setting of structural lesions (such as stroke or multiple sclerosis), medication side effects (seen with certain antidepressants and beta blockers), or neuronal loss from neurodegenerative disease. There is a known association between RBD and the group of neurodegenerative conditions classified as alpha synucleinopathies. RBD is considered a prodrome of these conditions and can be present years before other neurological symptoms become apparent, thus the importance of early diagnosis and subsequent monitoring [5].
