What is Sleep?

Little movement—walking, talking, writing, etc., usually preclude a judgment of sleep.

A stereotypic posture — usually we are lying down when we are asleep, and with rare exception, it is safe to say that people who are, for example, standing on their hands, are not asleep.

A reduced response to stimulation — we do not respond to low intensity sounds, touches, etc., which we would be aware of instantly during wakefulness.

Reversibility — we know that we can readily awake from sleep, which distinguishes it from coma or death.

Sleep is Heterogeneous

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5Copyright © 2004 Allyn and Bacon

Divisions of Sleep Stages

REM sleep:A period of desynchronized EEG activity during sleep,

at which time dreaming, rapid eye movements, and muscular paralysis occur.

Non-REM sleep:All stages of sleep except REM sleep.

Slow-wave sleep:Stage III and Stage IV of Non-REM sleep ,

characterized by slow, high amplitude (Delta Waves) synchronized EEG activity.

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Sleep is Cyclical

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Neurobiology of Sleep

Sleep is NOT simply the diminished function of waking systems.

Sleep is an active physiological process requiring the co-ordination of a slew of neurotransmitters and “sleep factors” acting simultaneously at different areas of the brain.

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Activation of GABA neurons in PONS

Decreases activity in NE (Locus Ceruleus) and Serotonin (Raphe Nuclei) systems

Increases ACh release (Pontine Nuclei)

Activates glutamate neurons in Pons

Glutamate neurons activate Glycine neurons in the Medulla

Glycine neurons fire onto and inhibit motor neurons in the Spinal Cord causing sleep paralysis

Deactivates rhythmic synchronous firing patterns in Thalamus causing asynchronous waves of REM sleep in cortex

Sleep Disorders

Categories of Sleep Disorders

DyssomniasProblem with quantity, quality or timing of

sleep.Parasomnias

Relatively normal quality, quantity and timing of sleep, but something odd happens during sleep itself or during the times when the patient is falling asleep or waking up.

Dyssomnias

Insomnia Not enough sleep is usually the presenting

complaint (for at least a month). Usually as a result of an Axis I or II or general

medical condition (rarely shows up by itself). MUST evaluate the cause of the Insomnia for

proper treatment decisions. If no other Axis I, II or III disorders are made then

it’s: Primary Insomnia

Dyssomnias

Primary Hypersomnia Presenting complaint is that they sleep too much. Usually fall asleep quickly and sleep late the next

day. Frequently complain of being chronically tired and

sleepy during the day (may take naps) Sleep 9+ hours/day

Dyssomnias

Narcolepsy Four major symptoms (do not have to have all of

them): Sleep attacks

Irresistible urge to fall asleep. Cataplexy

Sudden bilateral loss of muscle tone Hallucinations (usually visual)

Hypnagogic or hypnopompic Sleep paralysis

Sensation of being awake, but unable to move, speak or even breathe adequately

Associated with anxiety and fear of dying (lasts < 10 mins)

Narcolepsy

REM sleep intrusions Uncommon, chronic, largely hereditary disorder that is

difficult to manage & requires lifelong treatment. No gender differences. Onset is usually in puberty –

always before age 30. Slow steady progression of symptoms Can lead to depression, impotence, work problems,

accidents Not related to a general medical condition or

substances/medications Treatment: Stimulants (e.g. Ritalin)

Breathing-Related Sleep Disorder

Low oxygen levels in bloodCauses insomnia or hypersomniaSymptoms

Alveolar hypoventilation syndromeSleep apnea (relatively common)

ObstructiveCentral

Use Axis III to specify which medical condition

Circadian Rhythm Sleep Disorder

Circadian comes from about one day (circa = approximately; dia = day)

Presenting problem: sleep-wake cycle is off NOTE: this cycle is not constant through the

lifespan Two major types of Circadian Rhythm Sleep Disorder

Jet Lag Type Shift Work Type

Dyssomnia NOS

Complaints of clinically significant insomnia or hypersomnia related to the environment (e.g. airlines, trains, lights)

Restless legs syndromeSleep deprivation sleepiness.

Parasomnias

These are problems that encroach on sleep but don’t cause insomnia or hypersomnia.

ExampleNightmares vs. Sleep apnea

Scary vs. causing sleepiness during the next day

Nightmare Disorder

Nightmares occur during REM sleep Those that occur during childhood have no

pathological significance. Nightmares are very common – when does it

become a disorder? Vivid nightmares sometime precede a psychosis. However most Nightmares are normal a reaction to stress

Sleep Terror Disorder

Usually affect children (not pathological) Occur during non-REM sleep (most common

early during the night). Attack lasts 5-15 minutes and ends with the

individual going back to sleep. In adults the disorder is rare and usually

coincides with another Axis I disorder (anxiety?) or a personality disorder.

Sleepwalking Disorder

Usually occurs during first third of the night (non-REM sleep)

Some purposeful behavior is not uncommon (dressing, eating, using bathroom) but facial expression is blank and speech is either non-existent or garbled.

Usually have amnesia regarding incident Incident can last from a few seconds to 30 minutes. Hard to reawaken (not dangerous) 1-5% of children, <1% of adults

Parasomnia NOS

Sleep paralysis\BruxismSleep-related cluster headaches

Sleep disorders related to another Mental Disorder

Depression Anxiety disorders Adjustment disorders Somatization disorders Cognitive Disorders Manic/Hypomanic Episodes Schizophrenia