The objective of this course is to give students the most up-to-date information on the biological, personal, and societal relevance of sleep. Personal relevance is emphasized by the fact that the single best predictor of daytime performance is the quality of the previous night's sleep. The brain actively generates sleep, and the first section of the course is an overview of the neurobiological basis of sleep control. The course provides cellular-level understanding of how sleep deprivation, jet lag, and substances such as alcohol, ,caffeine, and nicotine alter sleep and wakefulness. The second section of the course covers sleep-dependent changes in physiology and sleep disorders medicine. Particular emphasis will be placed on disorders of excessive sleepiness, insomnia, and sleep-dependent changes in autonomic control. Chronic sleep deprivation impairs immune function and may promote obesity. Deaths due to all causes are most frequent between 4:00 and 6:00 a.m., and this second section of the class highlights the relevance of sleep for preventive medicine. The societal relevance of sleep will be considered in the final section of the class. In an increasingly complex and technologically oriented society, operator-error by one individual can have a disastrous negative impact on public health and safety. Fatigue-related performance decrements are known to have contributed as causal factors to nuclear power plant failures, transportation disasters, and medical errors.
05.04 - Classification of Sleep Disorders
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Sleep: Neurobiology, Medicine, and Society
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Unit 05 - Medicine: Overview of Sleep Medicine - Ronald Chervin, M.D. - (Standard Track)
Unit 5 marks the beginning of the Medicine section of the course. This unit features an overview of Sleep Medicine from Ronald Chervin, M.D.
Rencontrer les enseignants
Ralph Lydic, Ph.D.Professor Emeritus, Molecular and Integrative Physiology, Professor Emeritus, Anesthesiology
University of Michigan Medical School
Helen Baghdoyan, Ph.D.Professor Emeritus, Anesthesiology, Professor Emeritus, Pharmacology, Professor of Psychiatry
University of Michigan Medical School
So the most commonly used classification for
sleep disorders is the International Classification of Sleep Disorders.
Addition three just came out, this year in 2014.
And basically it's like the DSM-4, the Diagnostic and
Statistical Manual for psychiatry, and now the DSM-5.
It's a book that lists 80 plus types of sleep disorders, but not only lists them,
but tells you what the diagnostic criteria are, what the typical history is,
what the typical findings, what the typical prognosis is.
And so that's the kind of nosology I'll be introducing you
to right now as a broad overview of the segments of that book and
how sleep disorders are classified.
So the first section of the book is about insomnia and there's chronic insomnia
disorder and there are several types or subtypes of chronic insomnia disorder.
So one is pyschophysiological insomnia, another is inadequate sleep hygiene.
And another example would be behavior insomnia of childhood.
These are examples, but they're common examples.
So psychophisiological insomnia is the type where
someone not only has long ongoing difficulty with insomnia.
Taking, for example, a half-hour or more to fall asleep or
having multiple awakenings, or long periods of awakenings during the night,
or waking up in early morning hours before they want to get up.
But the reason in psychophysiological insomnia usually has to do with concern
about sleeping.
So concern, or you might say overconcern about sleeping,
actually promotes the insomnia itself.
And this is a very common type of sleep disorder.
There's also a condition component to it where
it becomes a habit of being awake at certain parts of the night.
And once someone is in that habit, it's hard to break it.
Inadequate sleep hygiene has to do with behaviors or
choices or habits that people make in their daily lifestyle
that are not conducive to good sleep and result in sleep problems.
For example, it might not be the best thing to have a lot of caffeine
in the hours leading up to sleep.
And that would be an example of inadequate sleepy hygiene if the person is suffering
the consequences with insomnia.
Behavioral insomnia of childhood is extremely common.
Many children go through at least phases of having that while they're young.
There's different subtypes even within that.
So for example, sleep onset association disorder is one type in which
a child learns to have a parent by the bedside or by the cribside usually.
When they're going to sleep and then if they wake up during the night,
they learn to associate the pattern with their sleep, and/or with going to sleep.
And they can't go to sleep unless the parent comes back.
So they cry until the parent comes back and
that can lead to quite a difficult night.
Or a series of weeks or
months or sometimes even years of difficult nights for the parent.
Fortunately all these types of insomnia disorders are usually quite treatable.
And we can usually treat them now by behavioral cognitive techniques
often without chronic use of medication.
Another example more broadly of insomnia would be short-term insomnia disorder or
adjustment insomnia.
And that's a very common form that you probably all experienced
at one point or another.
Family member dies, other major challenges in life
are often accompanied by temporary period of insomnia.
So the second large category of sleep disorders are sleep disordered breathing
and within that there's obstructive sleep apnea that we've talked about a little
already.
Extremely common, results for obstruction in the throat.
There's also another type of sleep apnea were there's also pauses in breathing but
it's not from obstruction in the throat.
In central sleep apnea the effort to breathe actually stops for periods.
And that's because usually the brain is not telling, for
one reason or another, the diaphragm to move, and
it's not orchestrating the breathing process for those temporary periods.
Less common than obstructive sleep apnea, but still can be consequential.
Often occurs in the setting of other types of health conditions.
And then sleep-related hypoventilation would be another
example where the diaphragm is moving and
there are not discreet periods where it stops moving or the throat obstructs.
But for one reason or another the person is not moving enough air in and
out, hypoventilating during the night,
during sleep with increases in carbon dioxide levels.
The next big category is called Central Disorders of Hypersomnolence and
these are some types to illustrate that.
There's narcolepsy type 1 and narcolepsy type 2 now.
Narcolepsy type 1 is the type that usually occurs with cataplexy or,
where the person eventually develops cataplexy.
Narcolepsy is a disorder where the person is very sleepy and
it comes from the brain.
In type 1, we know that the cause is a deficiency of a specific neurotransmitter,
hypocretin, also called orexin.
And sometimes it occurs near the onset or sometimes later develops cataplexy,
which is a sudden loss of muscle tone in response to laughter or
other emotion or surprise.
Narcolepsy type 2 in contrast,
has the same pretty much type of daytime sleepiness issue.
But is not so clearly due to a total deficiency of orexin or
hypocretin and does not involve cataplexy.
Idiopathetic hypersomnia we assume is a sleepiness due to a central nervous
system cause.
But we, in these cases, can't identify what that cause is.
It doesn't qualify for narcolepsy of either type, and
we end up calling it idiopathic hypersomnia.
It can often occur with long nocturnal sleep periods.
Kleine-Levin syndrome is sometimes in the past has been called recurrent
hypersomnia.
And what it is a very severe sleepiness and excess of sleep, for
a periods of days to a couple of weeks typically.
And then weeks or months of normal alertness and normal function,
only to be broken again by a recurrence of the period of sleepiness.
Next big section is Circadian Rhythm Disorders and these are disorders
in which the brain clock is not functioning like it is in most people.
And usually problems arise because of disjoints between
the expected requirement for that brain to be awake and
functioning at times when everybody else is and its ability to do so.
So one type is called delayed sleep-wake phase disorder.
Very common disorder.
It affects most commonly teenagers and young adults.
And it happens at that age probably because the natural
clock is a little bit longer.
So whereas many, most of us have a natural tendency to.
Surviving live on a 24 hour or near 24 hour cycle.
And at those ages, sometimes the clock can be a little bit longer and
I think if it gets too long, there's a tendency to sleep later in the morning and
to go to sleep later at night.
And people with sleep wake fails disorder do find.
If they're allowed to go to sleep very late and get up very late, but
when they have to get up at a regular time for a morning class or
to be at work on time, they can encounter substantial difficulty doing so.
Another example would be non-24-hour sleep-wake rhythm disorder
where people clearly have a non-24 hour rhythm.
And consequences from it.
Jet lag disorder, probably many of you have experienced when you cross time zones
and take a while to adjust.
And then, finally, shift work disorder.
Shift work is relevant, it turns out, to about 10% of our society.
So many people are on shifts that are other than the usual 9 to 5 or
8 to 5 kind of work day.
And problems arise not so much from having a different,
as a consequence sleep period and the timing of that sleep period.
But consequences arise when that sleep period is constantly changing.
And people who work shift work often if not always
have a tendency to shift back on the days that they're not working to, quote,
regular schedule and that cost and shifting
turns out to be much faster when than the brain can readily adjust and accommodate.
And the results can be some serious sleepiness during periods
when the person is trying to be awake to function or work or enjoy their lives.
Another big category, parasomnias, this are unwanted or
unusual out of an ordinary behaviors that are occurring during sleep.
An example would be sleepwalking, sleep terrors and sleep-related eating disorder.
All of these are disorders that occur with partial arousal from non-REM sleep.
And they can be normal, the first two can be normal part of being a young child.
If they persist past young childhood they can be more concern.
They can also occur in the context of another sleep disorder that is disturbing
sleep and partially arousing them, and then triggering these behaviors.
Sleep walking doesn't necessarily have to be just walking.
It can involve other types of behavior without getting out of bed.
Sleep terrors are where typically a young child will wake up inconsolable,
crying, and screaming that can last for
minutes and then the person will just go back to sleep and
have no memory of it typically the next day.
But the parents often do because it's such a frightening experience to see
a child in such a state of apparent terror.
Sleep-related eating disorder occurs when people are actually getting out of bed
at night while not completely conscious, and eating various foods, often foods
that they're trying not to eat during the day, if they're on a diet, for example.
And many times they'll have no memory of eating during the night except
that they'll find the evidence of food packages and on places or bowls and
spoon on positions on it in the morning.
REM sleep behavior disorder is another class of these parasomnias,
as you can guess it occurs during REM sleep.
And as opposed to childhood sleep walking or sleep terrors,
typically REM sleep disorder behavior will occur in later life.
And in REM sleep behavior disorder, a patient will actually act out his or
her dreams.
They're often violent in dreams, too.
So the patient maybe punching the air or attacking a bureau or furniture or
in for a concerning cases, even attacking or defending themself
against a bed partner who is perceived in a dream as attacking them.
And interestingly,
this type of parasomnia not always,
but very often is a prelude to a neurodegenerative disorder.
One of the Parkinson related disorder, Parkinsonism,
can often develop sometimes many years after the onset of this parasomnia.
But the parasomnia can also occur in response to certain medications or
other conditions.
And another example of parasomnia would be sleep enuresis, or bed wetting.
There are sleep related movement disorders, an example and
perhaps one of the most common is restless leg syndrome.
This is a sensory motor disorder in which someone
describes typically just the sensation of needing to move
their legs, sometimes it can affect the other parts of the body,
the upper extremities, but typically the legs during the night.
It's worse in the evening hours.
It's worse when the person is still.
And the feeling goes away when they move their legs.
So many of these patients lie down at night to go to bed,
that's the time when it becomes worst and they can't go to sleep because of their
legs feel just have the sensation that they have to move them.
And they end up having to get up and walk.
And as you can imagine can interfere with their sleep.
Periodic limb movement disorder is a condition where
the legs kick intermittently during the night,
every 20, 30, or 40 second intervals, the legs will kick.
It can be one leg, it can be one leg for a while, and
then the other leg, sometimes with both legs.
The periodic leg movements often occur in restless leg syndrome.
Probably 80% of patients with restless legs have the periodic leg movements.
But the periodic leg movements can occur by themselves without the restless
leg syndrome.
And if they're causing insomnia or
daytime sleepiness, then we would call it periodic limb movement disorder.
Bruxism is extremely common.
Few people don't have bruxism or tooth grinding at one point or
another during their life,
but when it occurs during the sleep period, we call it sleep-related bruxism.
Can be increased with stress and other precipitants.
And then, finally, another example is sleep-related rhythmic movement disorder
such as repetitive head banging, or body rocking,
that can occur as a person is going to sleep, sometimes even during sleep.
And they can occur recurrently through the night.
So here I'm going to show you or
give you an opportunity to watch a video that shows an example of parasomnia.
And I'll talk about it briefly after you've had a chance to watch it.
Okay, so I hope you got to watch that example of a parasomnia.
That was sleep groaning, or more officially called catathrenia.
Not a lot is known about the parasomnia.
We don't think it's terribly common.
But it is interesting and sounds rather dramatic, so
it's why I wanted to show you an example.
Typically, that groaning or moaning sound happens with these long and
prolonged expirations.
And some people have hypothesized that it might relate in some way to obstructive
sleep apnea, but we really don't know very much about this parasomnia.
So we'll go to this, which is another video, and
this is an example of a sleep-related movement disorder.
So in that video, what you were watching was sleep-related bruxism
in a child and what you could see Very well was
that there was some teeth grinding, and especially you could hear it.
And there are some cases that are even quite a bit louder than that, and
that can be quite difficult for a bed partner to tolerate during the night.
Interestingly, this disorder is not thought to really have bad consequences,
usually for the person's sleep, but it could have bad consequences for
their teeth.
And so, one of the first things that we do in a bad case would be to make sure that
someone has a dentist who can make a protective splint for
the person to wear during the night, so they're not grinding teeth against teeth.
Now here's another example of a sleep-related movement disorder.
For those of you who didn't recognize it, this sleep-related movement disorder
was actually periodic limb movements during sleep or
actually you can hear specifically periodic leg movements during sleep.
When you saw those relatively brief contractions,
dorsiflexion of the foot and that’s rather typical.
They can be even more pronounced with even more kicking when the bed finally gets
kicked inadvertently, but that's what we are talking about seeing in many patients.
Who also have restless leg syndrome, but
also in other patients who don't have restless leg syndrome and
aren't complaining about anything with regard to their legs.
And occasionally, if someone does have complaints about their sleep and
we think that the leg movements might have something to do with it.
And here l will show you another or
you can look at another sleep-related movement disorder.
So if you watch that example, a sleep-related movement disorder.
What you saw was,
a child with head banging combined with an element of body looking.
And that kind of movement disorder can typify each night of a patient's sleep,
they'll typically start doing that while they're trying to go to sleep.
But it can extend into sleep, and
sometimes occur periodically through the night.
And we don't generally see that has grave consequences for
how refreshing sleep is, where for next day function,
it can have consequences for the safety of someone's cranium.
So in a bad case of head banging,
where some patients have been even known to damage the wall or a bed board.
We'll make sure that someone is wearing a helmet while they're sleeping.
And next, I'm going to ask you to take a look at two examples here of parasomnias.
So if you watch those two videos, they both show the same type of disorder,
REM sleep behavior disorder.
In the first one, you saw an older person lying calmly and sleeping in the bed.
And then suddenly, things became less calm and you saw him kind of punching,
punching, we don't know what in his dream.
It looked like slapping or hitting the bed at one point.
And most likely he was dreaming of a fight and
he was defending himself or possibly attacking someone, but
usually it's a situation of threat where the person is having an aggressive dream.
In the second video, you saw a similar behavior in another individual, but
you got to see at the same time that you were watching polysomnogram signals.
And what you saw was, at one point the signals became much more active.
For example, the brain waves and the muscle tone.
And at the same time you got to see that the person was starting to do things
consistent with what you were seeing in the signals in terms of punching the air
and having another one of these episodes of acting out a dream.
So at this point, I'd like to shift gears and talk a little bit about a specific
sleep disorder that serves very well as an example of what sleep disorders
can do to general health, but also as a prototype for other sleep disorders.
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