An alarming sleep pattern
Some patients never do more than stub a toe as they stagger about in the dark. Others end up requiring emergency treatment for severe injuries. Still others don’t harm themselves but may seriously injure their bed partners with violent punching or kicking. Remarkably, these are all symptoms of a medical condition that arises only when a sufferer is fast asleep.
REM sleep behavior disorder, or RBD, is a misunderstood and often misdiagnosed problem. For reasons that aren’t clear, men make up more than 85% of people with RBD, which affects about one person in 200. Experts believe RBD could be more widespread, however, since some sufferers might not discuss the behavior with their physicians, fearing they’ll be labeled spouse abusers. What’s more, some men who do talk about their nighttime rampages with a therapist or doctor may receive an outdated diagnosis: that acting out violent nightmares is a nocturnal expression of bottled-up anger.
“That’s exactly what a lot of these men and their spouses have been told by psychologists or psychiatrists,” says Dr. Bradley Boeve, a neurologist at the Mayo Clinic in Rochester, Minn. Rather than displays of anger, Boeve and other researchers say, these dream-induced fits of rage are caused by a glitch in the brain’s wiring.
Recent studies hint at the cause of RBD, which appears to be closely related to more serious neurological diseases. Other current research offers new clues about how RBD patients can get a more-peaceful night’s rest.
When most of us doze off and enter the dream-filled state known as REM sleep, our muscles become paralyzed (other than an occasional twitching limb and the “rapid eye movement” that gives this phase its name). Scientists assume that this phenomenon prevents us from acting out our dreams. For some reason, people with RBD don’t become paralyzed during REM sleep. Instead, they are free to flail about or climb out of bed as if they stepped into the nightmares playing in their heads.
Boeve and two colleagues studied the characteristics of 93 RBD patients and published their findings in a 2000 article in the scientific journal Brain. They found that 32% of the patients had injured themselves. Sometimes the damage was minor. Boeve knows of at least three cases, however, where patients banged their heads on bedposts or other hard objects with enough force to produce blood clots that required emergency surgery.
More troubling was the finding that 64% of the patients in the study had assaulted their bed partners while having a nightmare. (Not surprisingly, RBD can interfere with intimacy; in 15% of the cases Boeve studied, spouses had chosen to sleep in another room, and one patient erected a plywood barrier to keep himself away from his wife.) In nine out of 10 dreams that produced this violent behavior, RBD patients believed they were defending themselves, family members or friends against an attacker.
RBD is often thought of as a condition that afflicts aging males; the typical patient is about 60. But Boeve has diagnosed the condition in men in their 20s and 30s.
Ironically, he has found that patients tend to be mild-mannered sorts. Their late-night fury, he says, “is 180 degrees from their personality profile during the day.”
Although RBD wasn’t identified as a distinct medical condition until 1986, scientists are slowly piecing together clues about its cause.
For instance, it’s known that RBD sufferers tend to have low levels of the brain chemical dopamine, which transmits nerve impulses. In a study published in the journal Neurology in July, University of Michigan researchers found that subjects who had the lowest brain supply of dopamine tended to have the most active limb muscles during REM sleep.
Dopamine levels are also diminished in people who have Parkinson’s disease and other conditions caused by the degeneration of nerve cells in the brain. Researchers believe that RBD is linked to these so-called neuro-degenerative conditions, but they aren’t sure how. Clues are emerging, however. Scientists have already identified the brain region where Parkinson’s disease appears to arise. By studying cats, UCLA neurobiologist Yuan-Yang Lai and a colleague recently located the region where they believe the damage that leads to RBD begins.
“These two areas are adjacent to one another,” says Lai.
Not surprisingly, Boeve found that about half of the RBD patients he studied eventually developed Parkinson’s disease or one of several other related neurological conditions. Boeve says that developing RBD doesn’t mean a person will definitely develop Parkinson’s or related diseases, but it may serve as a useful warning that a patient should be monitored closely for signs of neurological decline.
Doctors advise patients with RBD to remove potential weapons from the bedroom and even to place cushions or a mattress around the bed.
RBD responds well to medication; about 90% of patients who take the anti-anxiety drug clonazepam (sold as Klonopin) have fewer violent episodes. But some patients cannot tolerate the drug’s side effects, including drowsiness and loss of muscle coordination.
For many RBD sufferers, though, there’s no medicine like being freed from the guilt of believing that they harbor deep-seated aggression toward their spouses. “Once they learn it’s a medical or neurological problem,” says Boeve, “I think they’re quite relieved.”
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Timothy Gower can be reached at tgower@comcast.net. The Healthy Man runs the second Monday of the month.
