REM sleep behavior disorder

A diagnosis of REM sleep behavior disorder (RBD), a disorder characterized by “acting out” of dreams during REM sleep, has critical implications for a patient’s future. Aside from being a treatable parasomnia, usually managed with melatonin or clonazepam, RBD is the most powerful risk factor for Parkinson disease and dementia with Lewy bodies yet discovered. Over 70% of patients with idiopathic RBD will develop a neurodegenerative synucleinopathy. Moreover, the disease course is more severe in patients with RBD than those without. Numerous screens have been developed to aid detection, and clinical history can help distinguish RBD from NREM parasomnia. However, final diagnosis relies on polysomnographic documentation of REM atonia loss. Given the profound implications of idiopathic RBD, patients need careful counseling and the offer of neurological follow-up to detect and treat prodromal disease symptoms. Recognition of RBD is also a means to discover and test protective therapies against neurodegenerative disease.