By Mark W. Mahowald, M.D.
A 59-year-old man was referred to the sleep clinic for evaluation of potentially violent behaviors during his sleep. These had been occurring for two years. Initially there were primarily loud vocalizations and shouting (on occasion loud enough to awaken him), but over time becoming associated with complex behaviors such as punching, flailing about and occasionally falling out of bed. Along with the vocalizations and behaviors, his dreams had become much more violent and action-packed. The dream content often involved being chased, and if he was awakened during or immediately after a period of complex behavior, he was often able to recall a dream that perfectly correlated with the observed behavior.
He was taking no prescription medication and did not use alcohol or recreational drugs. There was no family history of similar behaviors, and no family history of Parkinson's disease or dementia. He had a recent history of erectile dysfunction and constipation. On examination, there was no evidence of any neurologic abnormalities suggestive of Parkinson's disease or dementia.
Due to the potentially violent or injurious nature of these spells, a formal sleep study was performed. There was no evidence of seizure activity or sleep apnea. During rapid eye movement (REM) sleep, there was prominent muscle activity with vocalization and twitching of arms and legs. This finding of prominent motor activity during REM sleep coupled with the history of dream-enacting behavior confirmed the diagnosis of REM sleep behavior disorder (RBD).
He and his wife were told that these behaviors were not the manifestation of underlying psychiatric or psychological problems such as "repressed hostility," depression or anxiety. They put the mattress on the floor and removed all furniture from near the bed. Heavy curtains were installed over the windows. He was placed on clonazepam 0.5 milligrams a half hour before bedtime with a marked reduction in the frequency and severity of the episodes.
On follow up five years later, signs of early Parkinson's disease were now apparent.
REM Sleep Behavior Disorder (RBD)
RBD is a fascinating experiment in nature. One of the defining features of REM sleep is paralysis of all body muscles except for the diaphragm (which is spared to permit breathing during REM sleep). This paralysis is probably a good thing, as our brains are often more active during REM sleep than they are when we are awake. This paralysis prevents us from acting out our dreams. Individuals with RBD lack the anticipated paralysis of REM sleep and can act out their dreams -- occasionally with potentially violent or injurious consequences. Many patients adopt self-protective measures such as tethering themselves to the bed, using sleeping bags or pillow barricades or sleeping on a mattress in an empty room. The resulting injuries to the patient or bed partner may result in forensic medicine issues.
The prevalence of RBD is 0.5 percent of the adult population, and it is more common in men over 55 years of age (however, recently younger individuals and more women with RBD are being identified). Initially RBD was felt to be an isolated neurologic condition. As more patients were identified and followed closely over time, it became apparent that many (over half) would eventually develop a degenerative neurologic condition -- most commonly Parkinson's disease or dementia with Lewy body disease. In many cases, the interval between the onset of RBD and the first appearance of any other manifestation of the underlying neurologic condition is very long -- often decades. Therefore, RBD may be a very early harbinger of these other neurologic conditions.
RBD may also be a manifestation of narcolepsy, a sleep disorder characterized by excessive daytime sleepiness. Many widely prescribed antidepressant medications, particularly the selective serotonin re-uptake inhibitors (such as Prozac, Celexa and Effexor) may either cause RBD or unmask underlying asymptomatic pre-clinical RBD.
Since RBD may be confused with other sleep disorders, a formal sleep study (with extensive muscle activity monitoring and continuous video monitoring) is mandatory.
RBD is often confused with disorders of arousal (confusional arousals, sleepwalking or sleep terrors). Following an RBD event, arousal from sleep to alertness and orientation is usually rapid and accompanied by complete dream recall (in contrast to disorders of arousal). The behaviors, although complex and violent, are of briefer duration than those seen in the disorders of arousal. The violent and aggressive nature of the sleep-related behavior is often discordant with the waking personality.
The patient (and bed partner, if present) should be reassured that these behaviors are not intentional, and are not the manifestation of any underlying psychiatric condition such as "repressed hostility," depression or anxiety. The goal is to prevent sleep-related behaviors which may be extremely bothersome to a bed partner or result in injury to self or bed partner. The mainstay of treatment is environmental safety: potentially dangerous objects should be removed from the bedroom, cushions put around the bed or the mattress placed on the floor, and windows protected.
No double-blind controlled efficacy studies are available for any medication used to treat RBD. About 90 percent of patients respond well to clonazepam 0.5 to 2.0 milligrams, administered a half hour prior to sleep time. Melatonin at doses up to 12 milligrams at bedtime or pramipexole may also be effective.
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Zoccolella S, Savarese M, Lamberti P et al. "Sleep disorders and the natural history of Parkinson's disease: The contribution of epidemiological studies." Sleep Medicine Reviews 2011;15(1):41-50.
Mark W. Mahowald, MD., is a visiting professor at Stanford Center for Sleep Sciences and Medicine. This Center is the birthplace of sleep medicine and includes research, clinical, and educational programs that have advanced the field and improved patient care for decades. To learn more, visit us at: http://sleep.stanford.edu/
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