Rapid eye movement sleep behavior disorder





Rapid eye movement sleep behavior disorder or REM behavior disorder (RBD).



A sleep disorder in which individuals act out their dreams. 



RBD prevalence is estimated to be 0.5–2% overall, and 5–13% of those aged 60 to 99.



Typical onset is in the 50s or 60s, and more common in males overall.



It is of equally frequency among men and women below the age of 50.



It is referred to as a  parasomnia.



It is categorized as either idiopathic or symptomatic.



Idiopathic RBD is not associated with another ongoing neurological condition.



When associated with an underlying etiology, it is referred to as symptomatic RBD.



It involves abnormal behavior during the sleep phase with rapid eye movement sleep. 



Its major feature is loss of muscle atonia during otherwise intact REM sleep.



During REM sleep paralysis is normal and necessary.



The most vivid dreaming occurs during REM sleep.



The loss of motor inhibition in this disorder leads to a wide spectrum of behavioral release during sleep. 



The abnormal movement behavior with this disorder extends from simple limb twitches to more complex integrated movement. 



Behaviors can be violent in nature and can result in injury to either the individual or their bedmates.



RBD is a strong predictor of progression to a synucleinopathy: Parkinson’s disease or dementia with Lewy bodies.



90% of individuals with idiopathic rapid eye movement sleep behavior disorder eventually develop related neurodegenerative diseases, usually PD or a related condition such as dementia with Lewy bodies or multiple system atrophy.



It is manifested  by the patient acting out their dreams, with complex behaviors, and include screaming, shouting, laughing, crying, arm flailing, kicking, punching, choking, and even jumping out of bed. 



The individual with RBD may be unaware of these movements.



The underlying dreams are often involve violent or aggressive, and an attack theme like being chased by people or animals. 



Individuals with RBD may not be aware of having dreams.



In a normal sleep cycle, REM sleep may be experienced at intervals of between 90 minutes and two hours every night.



RBD episodes may occur some four times a night. 



In a rare case, they may only happen once a week or once a month.



RBD episodes occur more towards the morning hours because that is when REM sleep is more frequent. 



Upon awakening patients can usually recall the dream they were having, which will match the actions they were performing.



RBD as the first indication of an underlying neurodegenerative disorder, may begin years or decades before other the onset of another condition.



Almost half of those with Parkinson’s, at least 88% of those with multiple system atrophy, and about 80% of people with Lewy body dementia have rapid eye movement sleep behavior disorder.



It  is a very strong predictor of progression to a synucleinopathy: 


On autopsy examination: up to 98% of individuals with polysomnography-confirmed RBD are found to have a synucleinopathy.



In addition, symptomatic RBD can also be associated with narcolepsy, Guillain Barre syndrome, limbic encephalitis, and Morvan’s syndrome.



Additional symptoms in patients with RBD are: reduced motor abilities, posture and gait changes, mild cognitive impairment, alterations in the sense of smell, impairments in color vision, autonomic dysfunction,orthostatic hypotension, constipation, urinary problems and sexual dysfunction, and depression.



RBD can be caused by adverse reactions to certain drugs or during drug withdrawal.



RBD it is most often associated with the elderly and in those with neurodegenerative disorders such as Parkinson’s disease and other neurodegenerative diseases, for example multiple system atrophy and the Lewy body dementias.



It is likely that RBD is an early symptom of synucleinopathy rather than a separate disorder.



RBD associated with damaged brainstem circuits that control atonia during REM sleep, including  those in the pontomedullary brainstem.



REM sleep circuits are located in caudal brainstem structures.



These  same structures that are known to lead to be implicated in the synucleinopathies ((synucleinopathy)).



Risk factors for developing RBD: family history of acting out dreams, prior head injury, farming, exposure to pesticides, low education level, depression, and use of antidepressants.



It has been reported following a cerebrovascular accident suggesting damage to the brain stem area may precipitate RBD.



It is usually a chronic process, but may be acute and sudden in onset if associated with drug treatment or withdrawal: monoamine oxidase inhibitors, tricyclic antidepressants, selective serotonin reuptake inhibitors, and noradrenergic antagonists can induce or aggravate RBD symptoms.



The above drugs should be avoided in individuals with RBD.



Diagnosis: by


documenting complex, dream-enactment sleep behaviors, or by polysomnography recording of these behaviors along with REM sleep atonia loss.



RBD may be established from clinical interview, questionnaires, and bed partner observations.



Differential diagnosis: 



non-REM parasomnias-sleepwalking, sleep terrors



periodic limb movement disorder



severe obstructive sleep apnea



disassociative disorders



Polysomnography plays an important role in confirming RBD diagnosis among these processes.



Most strongly associated with RBD are the synucleinopathies, particularly Parkinson’s disease, dementia with Lewy bodies, and to a lesser extent, multiple system atrophy.



Melatonin and clonazepam are the most frequently used treatments.



They are equally  effective, but melatonin  a safer alternative, because clonazepam can produce undesirable side effects.



Medications: tramadol, mirtazapine, antidepressants, and beta blockers may worsen RBD.



Efforts to secure the sleeper’s environment by removing potentially dangerous objects from the bedroom, cushioning the bed or move the mattress to the floor for added protection against injuries.



Patients should maintain a normal sleep schedule, and avoid sleep deprivation.



Treatment includes regulating neurologic symptoms and treating any other sleep disorders.



Sleep deprivation, alcohol, 


 medications, and other sleep disorders can all increase RBD.



33%-65% of RBD patients have had sleep related injury to self or their partner. 



Prognosis: Most patients with RBD will convert to a synucleinopathy—usually Parkinson’s disease or dementia with Lewy bodies—within 4 to 9 years from diagnosis of RBD, and 11 to 16 years from onset of symptoms.



In patients with degenerative dementia, symptoms of RBD and/or sleep related injuries can decline over time.



Visuospatial and constructional impairments are also found in patients with idiopathic RBD.







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