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September 2, 2004
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  Sleep and Brain Chemistry    

Sleeping Yourself Sick (11.04.99) - During sleep apnea, people can repeatedly stop breathing for close to a minute at a time. Find out more about this sleep disorder and see the video of an apnea sufferer.

Catching Up On Sleep (1.07.03) - Why it’s important to catch up on your sleep.

Snooze You Can Use (11.07.01) - Hitting the snooze bar on your alarm clock every morning is a likely indication of sleep deprivaton, but a morning snooze or two may give you more than just some extra shut-eye.

  National Center on Sleep Disorders Research

You're Getting Sleepy - How Hypnosis Works

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Sleep disorders affect not only the nighttime slumber and daytime behavior of millions of Americans, but also their overall health. As this ScienCentral News video reports, some neuroscientists say sleep disorders could be associated with chemical imbalances in the brain.

To Sleep, Perchance to Dream

We all have trouble sleeping from time to time. But many Americans suffer from life-disrupting disorders like obstructive sleep apnea (OSA), where they actually stop breathing numerous times during sleep, sometimes for a minute or even more, and a less common disorder called REM sleep behavior disorder (RBD), in which patients literally act out the dreams they are having during REM sleep.

"Obstructive sleep apnea is associated with high blood pressure, heart attack, and stroke as well," says Sid Gilman, chair of the neurology department at the University of Michigan, while "people with [RBD] thrash, talk, sometimes pummel their bed partner. It’s usually the bed partner who complains rather than the person who has this disorder. Some people with this will actually get up out of bed or fall out of bed and injure themselves. It can be a very dramatic disorder."

Gilman says REM sleep behavior disorder likely affects half of 1 percent of the general population, whereas OSA affects likely 3 percent of the population.

Gilman and his colleagues say that chemical imbalances in the brain may be partly to blame for these disorders. They suspected this because patients who have a rare and degenerative brain disorder called Multiple System Atrophy, or MSA, suffer from both obstructive sleep apnea and REM sleep behavior disorder.

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To study this, researchers observed and videotaped sleeping MSA patients for two nights in a row, monitoring their heart rates, limb movements, and eye movements. During the day they scanned the subjects' brains to measure the levels of two important brain chemicals: dopamine, a transmitter used for communication between cells, and acetylcholine, a chemical important for learning and memory.

"We found that the lower the dopamine, the worse the REM sleep behavior disorder; and the lower the acetylcholine, the worse the obstructive sleep apnea," says Gilman. "These patients actually lose the brain cells which produce the chemicals. We controlled for which chemical in the brain was causing which disorder, so only the dopamine is related to REM sleep behavior disorder, and only acetylcholine to obstructive sleep apnea."

This correlation between sleep disorders and brain chemicals may lead researchers to the cause, and better treatments, of these disorders. But since they studied people with MSA, Gilman says this study doesn't prove that there's a direct link between chemical deficits and these sleep disorders in people who don't have MSA. "We’re planning to look at normal people who have sleep behavior disorders and OSA to see if they have these brain chemical abnormalities. That’s a key question in trying to establish causation. This opens the door about the influence of brain chemistry abnormalities to sleep disorders in people who are otherwise normal."

This research appeared in the July issue of the journal Neurology and was funded by the National Institutes of Health.

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