Purpose of Review: The most common rapid eye movement (REM) parasomnia encountered by neurologists is REM sleep behavior disorder (RBD), and nightmares are so frequent that every neurologist should be able to differentiate them from the dream enactment of RBD. Isolated sleep paralysis is relatively common and is often mistaken for other neurologic disorders. This article summarizes the current state of the art in the diagnosis of RBD, discusses the role of specific questionnaires and polysomnography in the diagnosis of RBD, and reviews recent studies on idiopathic RBD as an early feature of a synucleinopathy, secondary RBD, and its management. Recent diagnostic criteria and implications of nightmares and isolated sleep paralysis are also reviewed.
Recent Findings: Idiopathic RBD can now be considered as part of the prodromal stage of a synucleinopathy. Therefore, an accurate diagnosis is mandatory, and this implies detection of REM sleep without atonia. The polysomnography montage, including EMG of the submentalis and flexor digitorum superficialis muscles, provides a high sensitivity and specificity for the diagnosis. The exact diagnosis is important for patient counseling and for future neuroprotective trials.
Summary: REM parasomnias include RBD, sleep paralysis, and nightmares, which have distinct clinical characteristics and different implications regarding diagnostic procedures, management, and prognosis.
Address correspondence to Dr Birgit Ho¨gl, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, Innsbruck 6020, Austria, firstname.lastname@example.org.
Relationship Disclosure: Dr Högl serves as associate editor of the Journal of Clinical Sleep Medicine and receives personal compensation for serving on the advisory board of Mundipharma and UCB. Dr Ho¨gl has received honoraria for lectures for Abbvie, Eli Lilly and Company, Janssen Cilag, Lundbeck, Mundipharma, Otsuka Pharmaceutical, and UCB, and as a consultant for Axovant and Benevolent Bio. Dr Ho¨gl receives royalties from Cambridge University Press and Springer. Dr Iranzo has received personal compensation for serving on the advisory board of and as a lecturer for Otsuka Pharmaceutical and UCB.
Unlabeled Use of Products/Investigational Use Disclosure: Drs Högl and Iranzo discuss the unlabeled/investigational use of clonazepam and melatonin for the management of rapid eye movement sleep behavior disorder.
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