Rapid Eye Movement Sleep Behavior Disorder: Overview and Current Perspective

Rapid eye movement (REM) stage of sleep in normal circumstances is composed of vivid dream mentation associated with physiological skeletal muscle paralysis and thus, quiescence of motor activity. REM sleep behavior disorder (RBD) is a parasomnia characterized by disinhibition of motor control facilitating dream enactment behaviors. These nocturnal motoric behaviors due to lack of REM atonia range from benign limb movements to complex aggressive actions but are often manifested by violent, aggressive flailing, punching and kicking with vocalizations enacting action-filled hostile dreams. Polysomnographic evidence of increased electromyographic tone during REM with or without capturing clinical dream enactment together with careful history helps diagnose RBD. It is considered a prodromal feature of neurodegenerative alpha-synucleinopathies with high rate of eventual phenoconversion. The mainstay of treatment is to first ensure physical safety. When medications are necessary, options include either low-dose clonazepam, high-dose melatonin or both. Yearly surveillance with detailed neurological evaluation is vital for early detection and eventual management of neurodegenerative disorder.