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Normal sleep and sleep disorders
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Normal sleep
Awake state. Beta and alpha waves characterize
the electroencephalogram (eeg) of the awake
individual--Beta waves over the frontal lobes are commonly
seen with active mental concentration.
Alpha waves over the occipital and parietal lobes
are seen when a person relaxes with closed eyes.
Sleep state. During sleep, brain waves show
distinctive changes
 -sleep is divided into rem (rapid eye
movement) sleep and non rem sleep. non
rem sleep consists of stages 123and4
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Mapping the transitions from one stage of
sleep to another during the night produces a
structure known as sleep architecture
 Sleep architecture-changes with age .elderly
have poor sleep quality because aging is
associated with reduced rem sleep, delta
sleep and total sleep time and increased
night time awakenings
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sedative agents –barbiturates &
benzodiazepines ---reduced rem & delta
sleep.
 Delta sleep occurs during first half sleep
cycle.
 Longest rem periods occur during second
half
 Average time for first rem period—90 mts.
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Rem periods of 10-40 mts occur every 90
mts. throughout night
 Deprived rem sleep one night---has
increased rem sleep next time rem rebound
 Extended rem deprivation---transient
psychopathology---anxiety
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Rem ---commonly seen just before awakening
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Neurotransmitters are involved in the
production of sleep.
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--increased levels of acetylcholine (ach) increase
both total sleep time and rem sleep. Acetylcholine
levels, total sleep time and rem sleep decrease in
normal aging as well as in alzheimers disease.
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Increased levels of dopamine decrease total sleep
time . Treatment with antipsychotics, which block
dopamine receptors, may improve sleep in patients
with psychotic symptoms.
Increased levels of norepinephrine decrease both
total sleep time and rem sleep
Increased levels of serotonin increase both total
sleep time and delta sleep. Damage to the dorsal
raphae nuclei, which produce serotonin , decreases
both of these measures.
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Classification of sleep disorders
--the diagnostic and statistical manual of mental
disorders, 4th edition (dsm IV) classifies disorders
in two major categories
Dyssomnias are characterised by problems in the
timing , quality, or amount of sleep .they include
insomnia, hypersomnia, narcolepsy breathing
related sleep disorder (sleep apnea ), circadian
rhythm sleep disorder.
Parasomnias are characterized by
abnormalities in physiology or in behavior
associated with sleep. They include
sleepwalking, sleep terror disorder and
nightmare disorders.
 Insomnia, breathing related sleep disorder,
and narcolepsy.
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Insomnia
 Insomnia is difficulty falling asleep or
staying asleep that occurs 3 times per week
for at least 1 month and leads to sleepiness
during the day or causes problems fulfilling
social or occupational obligations. It is
present in 30% of the population. -
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Psychological causes of insomnia include
the affective and anxiety disorders.
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--major depressive disorder
---characteristics of the sleep pattern in
depression
-normal sleep onset
Repeated nighttime awakenings
-waking too early in the morning (terminal
insomnia) is the most common sleep
characteristic of depressed patients.
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Characteristics of the sleep stages in depression
1. short rem latency (appearance of rem within
minutes of falling sleep)
Increased rem early in the cycle and decrease rem
later in the sleep cycle (i.e in the early morning
hours) may lead to waking too early in the
morning.
3. long first rem period and increased total rem
4.reduced delta sleep.
Bipolar disorder. Manic or hypomanic
patients have trouble falling asleep and need
less sleep.
 Anxious patients often have trouble falling
asleep.
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Physical causes of insomnia
1. use of central nervous system stimulants (e.g
caffeine) is the most common cause of insomnia.
2. withdrawal of drugs with sedating action can
result in wakefullness.
3. medical conditions causing pain also result in
insomnia, as do endocrine and metabolic disorders
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Breathing –related sleep disorder (sleep apnea)
A. patients with sleep apnea stop breathing for
brief intervals. Low oxygen or high carbon di
oxide level in the blood awakens the patient
repeatedly during the night, resulting in daytime
sleepiness.
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1. in patients with central sleep apnea (more
common in the elderly), little or no respiratory
effort occurs, resulting in less air reaching the
lungs.
2. in patients with obstructive sleep apnea,
respiratory effort occurs, but an air way
obstruction prevents air from reaching the lungs.
obstructive sleep apnea occurs most often in
people 40-60 years of age, and is more common in
men (8:1 male to female ratio) and in the obese
(pickwickian syndrome) patients often snore.
Sleep apnea occurs in 1%-10% of the
population and is related to depression,
headaches, and pulmonary hypertension. It
may also may result in sudden death during
sleep in the elderly and in infants.
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Narcolepsy
 A. patients with narcolepsy have sleep
attacks (ie fall asleep suddenly during the
day) despite having a normal amount of
sleep at night
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B. narcolepsy is also characterized by
1. hypnagogic or hypnopompic hallucinations.
These are strange perceptual experiences which
occur just as the patient falls asleep or wakes up
,respectively, and occurs in 20-40%of patients. 2.
short rem latency. 3. cataplexy. This is sudden
physical collapse caused by loss of all muscle tone
after a strong emotional stimulus & occurs in 70%
of patients.
4. sleep paralysis—inability to move the
body for a few seconds after waking,
occurs in 30 – 50% of patients.
 Narcolepsy is uncommon. occurs in
adolescent & young adults
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Treatment----