One of the most fascinating — yet disturbing— sleep disorders is REM sleep behavior disorder (RBD).  This parasomnia is most commonly seen in older men, and symptoms can range from mild movements to violent thrashing. Injuries associated with RBD might include broken bones, lacerations, and concussions as the patient may strike the headboard or fall out of bed. Unfortunately, if there is a bed partner, they can also be injured as they try to calm the patient.¹ 

RBD is important to diagnose for 2 important reasons:  1) to keep the patient and bed partner safe; and 2) to monitor for the development of neurodegenerative diseases, such as Parkinson disease, Lewy body dementia, and multiple system atrophy.2 RBD is believed to be a prodromal syndrome of alpha-synuclein neurodegeneration.¹,² Although approximately 35 million people worldwide experience RBD,1 many cases go unrecognized.

All humans experience atonia during REM sleep; only vision and breathing remain unaffected so that we do not act out our dreams. As RBD can be confused with other sleep disorders, such as obstructive sleep apnea, exclusion of those conditions will be necessary to make an appropriate diagnosis. Sleep medications, antidepressants, and alcohol can cause RBD symptoms in some patients.¹

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New evidence suggests there are patients who may exhibit early symptoms of RBD, with isolated events of increased motor activity that may progress to clinically diagnosed RBD.1 Further studies are therefore needed to determine what percentage of these patients will go on to develop full-blown RBD. This could one day lead to neuroprotective interventions that we do not have currently.3

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When assessing a patient’s sleep, especially in elderly men, ask the patient’s sleep partner or caregiver if the patient appears to be fighting in his sleep or has substantial movements. You might be able to identify a disorder that could not only cause physical harm but might signal the beginning of a neurologic disease.                              


  1. Howell M, Schenck C. Rapid eye movement sleep behavior disorder. UpToDate. 2018.
  2. St Louis EK, Boeve BF. REM sleep behavior disorder: diagnosis, clinical implications, and future directions. Mayo Clin Proc. 2017;92(11):1723-1736.
  3. Ferri R, Aricò D, Cosentino FII, Lanuzza B, Chiaro G, Manconi M. REM sleep without atonia with REM sleep-related motor events: broadening the spectrum of REM sleep behavior disorder [published online September 15, 2018]. Sleep. doi: 10.1093/sleep/zsy187