Rapid eye movement sleep behavior disorder

RBD is characterized by the dreamer acting out their dreams, with complex behaviors.[2] These dreams often involve screaming, shouting, laughing, crying, arm flailing, kicking, punching, choking, and even jumping out of bed. The actions in an episode can result in injuries to oneself or one's bedmate.[2][1] The sleeping person may be unaware of these movements.[2][1] Dreams often involve violent or aggressive actions, and an attack theme like being chased by people or animals. Because violence in dreams is more likely to be recalled, this could be an artifact of recall bias or selection bias.[1] The individual with RBD may not be aware of having it.[4]

In a normal sleep cycle, REM sleep may be experienced at intervals of between 90 minutes and two hours every night, which means RBD episodes may occur some four times a night. In a rare case, they may only happen once a week or once a month. Episodes occur more towards the morning hours because that is when REM sleep is more frequent. When awakened, people can usually recall the dream they were having, which will match the actions they were performing.[5]

As the first indication of an underlying neurodegenerative disorder, symptoms of RBD may begin years or decades before the onset of another condition.[2]

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 RBD.[1] RBD is a very strong predictor of progression to a synucleinopathy (for example, the Lewy body dementias).[3] On autopsy, up to 98% of individuals with polysomnography-confirmed RBD are found to have a synucleinopathy.[3]

Symptomatic RBD can also be associated with narcolepsy, Guillain Barre syndrome, limbic encephalitis, and Morvan's syndrome.[4]

Other symptoms found 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.[4]

Rapid eye movement behavior disorder occurs when there is a loss of normal voluntary muscle atonia during REM sleep resulting in motor behavior in response to dream content. It can be caused by adverse reactions to certain drugs or during drug withdrawal; however, 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.[1][2]

The underlying cause of RBD is not well understood,[2] but it is likely that RBD is an early symptom of synucleinopathy rather than a separate disorder.[6] Brainstem circuits that control atonia during REM sleep may be damaged,[6] including those in the pontomedullary brainstem.[4] REM sleep circuits are located in caudal brainstem structures—the same structures that are known to lead to be implicated in the synucleinopathies.[6] Motor deficits like those seen in RBD are known to result from lesions in those circuits.[6]

Risk factors for developing RBD are a family history of acting out dreams, prior head injury, farming, exposure to pesticides, low education level, depression, and use of antidepressants.[4]

RBD has also been reported following cerebrovascular accident and neurinoma (tumor), indicating that damage to the brain stem area may precipitate RBD. RBD is usually chronic. However, it may be acute and sudden in onset if associated with drug treatment or withdrawal (particularly with alcohol withdrawal). Monoamine oxidase inhibitors, tricyclic antidepressants, Selective serotonin reuptake inhibitors, and noradrenergic antagonists can induce or aggravate RBD symptoms and should be avoided in individuals with RBD.

There are two ways to diagnose RBD: by documenting a history of complex, dream-enactment sleep behaviors, or by polysomnography recording of these behaviors along with REM sleep atonia loss.[2]

RBD may be established from clinical interview as well as several validated questionnaires, when sleep studies cannot be performed.[2][6] Questionnaires such as the Rapid Eye Movement (REM) sleep Behavior Disorder Screening Questionnaire (RBDSQ), the REM Sleep Behavior Questionnaires – Hong-Kong (RBD-HK), the Mayo Sleep Questionnaire (MSQ) and the Innsbruck REM Sleep Behavior Disorder Inventory are well-validated.[2]

Individuals with RBD may not be able to provide a history of dream enactment behavior, so bed partners are also consulted.[1][7] The REM Sleep Behavior Disorder Single-Question Screen offers diagnostic sensitivity and specificity in the absence of polysomnography with one question:[2]

"Have you ever been told, or suspected yourself, that you seem to 'act out your dreams' while asleep (for example, punching, flailing your arms in the air, making running movements, etc.)?"[8]

RBD is treatable (even when the underlying synucleinopathies are not). Melatonin and clonazepam are the most frequently used,[2] and are comparably effective,[11] but melatonin offers a safer alternative, because clonazepam can produce undesirable side effects.[7] Other medications and treatments are available, but have only anecdotal evidence.[12]

Medications that may worsen RBD and should be stopped if possible are tramadol, mirtazapine, antidepressants, and beta blockers.[2]

In addition to medication, it is wise to secure the sleeper's environment by removing potentially dangerous objects from the bedroom and either place a cushion around the bed or move the mattress to the floor for added protection against injuries.[2] Some extreme sufferers sleep in a sleeping bag zipped up to their neck, and wear mittens so they can't unzip it until they awake in the morning.[13][14]

Patients are advised to maintain a normal sleep schedule, avoid sleep deprivation, and keep track of any sleepiness they may have. Treatment includes regulating neurologic symptoms and treating any other sleep disorders that might interfere with sleep. Sleep deprivation, alcohol, certain medications, and other sleep disorders can all increase RBD and should be avoided if possible.[15]

Patients with RBD are at risk for sleep-related injury (SRI) : between 33% and 65% of RBD patients reported to have had sleep related injury to self or their partner.[16][17]

Most people 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.[4] For patients with degenerative dementia, symptoms of RBD and/or sleep related injuries can decline over time.[17] Visuospatial and constructional impairments are also found in patient with idiopathic RBD who had no other neurological disorder.[18]

RBD prevalence as of 2017 is estimated to be 0.5–2% overall, and 5–13% of those aged 60 to 99.[1] It is more common in males overall, but equally frequent among men and women below the age of 50.[2] This may partially be due to a referral bias, as violent activity carried out by men is more likely to result in harm and injury and is more likely to be reported than injury to male bed partners by women, or it may reflect a true difference in prevalence as a result of genetic or androgenic factors. Typical onset is in the 50s or 60s.[2]

In the 1960s and 1970s, Michel Jouvet described brain lesions in cats that led to loss of atonia in REM sleep.[2][19][20] Carlos Schenck and Mark Mahowald and their team in Minnesota first described RBD in 1986.[2][21]

RBD has also been diagnosed in animals; specifically dogs.[22]

• Sleepwalk with Me
• Pseudobulbar affect
• Gelastic seizure

• Roguski A, Rayment D, Whone AL, Jones MW, Rolinski M (2020). "A Neurologist's Guide to REM Sleep Behavior Disorder". Front Neurol (Review). 11: 610. doi:10.3389/fneur.2020.00610. PMC 7360679. PMID 32733361.
• Josh T. "Bed Time Calculator Based On REM Cycles". Cite journal requires |journal= (help)