[ ♪INTRO ] In the award-winning movie Sleepwalk with
Me, based on the one-man show of the same name, comedian Mike Birbiglia describes the
hilarious and often startling things his body does when he’s sleeping. Birbiglia has REM sleep behavior disorder,
or RBD, a sleep disorder that causes people to physically act out their dreams. And while that might sound goofy at first,
think about the last dream you had, where you were running from homework monsters or
throwing punches at Voldemort. Maybe… maybe you wouldn’t want to act
those out in real life. Thankfully, RBD can be treated. But in some
cases, it can also tell a deeper story about what’s happening in someone’s brain. RBD affects roughly 1% of the population — although
that number is slightly higher in older people. And it’s often associated with a huge range of things. We’re talking everything from pre-existing,
neurodegenerative diseases like Parkinson’s to narcolepsy to tumors to certain antidepressants.
But ultimately, it happens because something interferes with the brain during sleep. Typically, about 90 minutes after you fall
asleep, you begin the REM sleep stage. REM stands for “rapid eye movement,” because
it’s when your eyes move back and forth under your closed eyelids. But it’s also
the stage where you experience most of your dreams. During this time, your brain activity rises
to near-waking levels, and your breathing and heart rate speed up. But typically, your
body isn’t able to move. That’s because, during REM, structures in
the brainstem prevent the body from acting out dreams by relaxing muscles and suppressing
motor activity. Specifically, clusters of neurons from a structure
called the pons activate neurons in another structure called the medulla. Then, the medulla sends signals to motor neurons
in the spinal column to keep the muscles relaxed and put motor activity on pause. In RBD, that’s where the trouble lies. An
issue in the pons results in a failure to turn off those motor neurons, so someone can
move as much as they want during a dream. Now, to be clear, a little movement during
sleep is totally normal. What these brainstem areas do is stop big movements like kicking
and arm-swinging. Without this kind of inhibition, a person
might just knock a lamp off their nightstand or bruise themselves by kicking their footboard.
But for those who share a bed, this disorder can have more serious consequences. Like, in 1986 when RBD was formally identified,
researchers described men who would dream they were defending their wives from an attacker,
only to wake up and find they were actually attacking their wives. Which, understandably, would be pretty alarming.
It’s kind of thing that you do want to treat. And the very good news is, RBD is treatable,
and there are two medications research has shown to be effective. The first choice for many doctors is clonazepam,
a medication traditionally prescribed for seizures. It does come with a number of side effects,
including drowsiness, dizziness, and incontinence. But for some, that’s better than the alternative. The other medication is melatonin, the same
hormone our brains secrete to make us sleepy at night. It has minimal side effects, but
it only seems to work for some patients. Unfortunately, it’s not clear right now
why these medications work. But, they do seem to. This being said, even though RBD is treatable,
it’s still something doctors tend to keep a close eye on. Because sometimes, this condition
can signal that something bigger is changing in the brain. Earlier in this episode, I mentioned that
RBD is often associated with pre-existing neurodegenerative diseases, like Parkinson’s.
And that’s true. But researchers have also noticed another
connection here. They’ve found that many otherwise-healthy
people with RBD actually go on to develop neurodegenerative diseases later in life. For example, a 2009 study followed 93 patients
who had been diagnosed with RBD at a hospital’s sleep lab. People who had no other signs of
neurodegenerative disease. Researchers followed the health of these patients
for several years, and monitored who got diagnosed with what and when. Then, based on those results, they estimated
the risk of developing a neurodegenerative disease within 12 years after an RBD diagnosis.
And that risk was a whopping 52% — basically, a one in two chance. And other studies have
found similar results. Additionally, papers have identified RBD in
an average of 24% of existing Parkinson’s cases, 88% of cases of multiple systems atrophy,
and 76% of Lewy body dementia cases. As for why? Well, these conditions are all
types of alpha-synucleinopathies. Those are diseases caused by buildup of the
protein alpha-synuclein in — where else? — the brainstem. The same region of the
brain that causes RBD symptoms. Researchers aren’t sure exactly how all
of this is connected, and it’s something they’re still looking into. But there does
seem to be a link here between alpha-synuclein in the brainstem and RBD. Hopefully, as we figure it out, we’ll learn
more about how these diseases develop and progress. For now, though, RBD can at least be the canary
in the coal mine, letting people know something could be up a decade or more before they show
symptoms of full neurodegenerative disease. Again, not everyone with RBD will go on to
develop these conditions. But for those who do, treatments for these diseases are more
effective when they’re administered early. And that counts for a lot. REM sleep behavior disorder is a reminder
that our brains are big, connected systems. So, the more we learn about specific conditions,
the better-equipped we are to understand all kinds of other things. After all, research into this rare sleep disorder
could have a lot to teach us about some of the most common brain diseases. Thanks for watching this episode of SciShow
Psych. If the symptoms we just described are ringing a bell for you, consider reaching
out to your doctor. Because we can tell you a lot about what RBD is, but we’re definitely
not medical professionals and this is not a diagnostic tool. [ ♪OUTRO ]

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