Download Sleep and sleep disorders

Sleep and sleep
disorders
.
Definition
Sleep is an ACTIVE process. It is a reversible
state of unresponsiveness to stimuli of the
outside world and to responses within the
brain which underlie perception.
Sleep Architecture
Normal sleep has 2 essential phases :
- Non rapid eye movement sleep (NREM)
4 stages – strong reduction of
physiological functioning.
- Rapid eye movement sleep (REM).
highly active brain with physiological
levels similar to awake state .
EEG shows the following:
In the awakening state : Alpha waves (9
to 10 Hz ) = Alpha activity
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NREM sleep= S (Synchronized) sleep
(75 - 80%)
stage 1 : Law amplitude Theta waves (3 to 7Hz ) with vertex sharp waves = initiation
to sleep(5%)
stage
2 :Sleep spindles + triphasic k complex
= Light sleep (50% )
Slow Wave Sleep (SWS) = Deep sleep
( stages 3 & 4 ) (15-20%)
stage 3 : Delta waves represent 20%- 50% (½- 1 Hz with amplitude greater than 75 mV ) =
High voltage activity.
Stage 4 : Delta waves more than 50%
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In stages 3 &4(deep sleep) nocturnal enuresis
sleep walking & night terrors may occurs
Most of stage 4 occurs in 1st third of the night.
REM sleep D (Desynchronized ) sleep
Law amplitude mixed frequencies (Theta &Beta
waves) Sawtooth waves – rolling of eyes – Law
amplitude.
Most of REM sleep occurs in the last third of night.
1st episode occurs after a latency of 90 minutes
and is the shortest (less than 10 minutes) later
REM lasts from 15 to 40 minutes (4 to 5 episodes)
Features of non-REM sleep
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reduced recall of dreaming if woken
reduced complexity of dreams
increased parasympathetic activity
upward ocular deviation with few or no eye movements
abolition of tendon reflexes
decreased heart rate
decreased systolic blood pressure
decreased respiratory rate
decreased cerebral blood flow
penis not usually erect
Features of REM sleep
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increased recall of dreams if woken
increased complexity of dreams
increased sympathetic activity
transient runs of conjugate eye movements
maximal loss of muscle tone
increased heart rate
increased systolic blood pressure
increased respiratory rate
increased cerebral blood flow
occasional myoclonic jerks
penile erection or increased vaginal blood flow
increased protein synthesis (in rat brains)
Neuroanatomy of sleep
Wakefulness :
-Reticular formation
-Thalamic Nuclei (intra laminar & midline)
-Subthalamus
-Hypothalamus
SWS :
-Raphe Nuclei of Brain stem (sleep promotion)
-Thalamic Nuclei (non specific)
- Hypothalamus
Neurophysiology of sleep
Neurotransmitters of wakefulness:
-AcetylCholine (cortex)
-Noradrenaline (cortex)
-peptides
-Histamine
-Corticotrophin releasing hormone
-Thyrotrophin releasing hormone
-Vasoactive intestinal polypeptide
-ACTH & TRH
Neurotransmitters of SWS:
- GABA
-5HT ( acting to reduce sensory output to
inhibit motor activity )
-Alpha-melanocyte secreting hormone
- Somatostatin
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The monoaminergic model of the sleep-wake cycle
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· nREM sleep is associated with serotonergic neuronal activity,
originating in the raphe complex
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· REM sleep is associated with noradrenergic neuronal activity,
originating in the locus coerulus
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The cellular model of the sleep-wake cycle
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pontine gigantocellular tegmental fields (nucleus reticularis
pontis caudalis) –
acetylcholine – is responsible for causing the onset of REM sleep; these
are known as the ‘on cells’
these cells are inhibited by the dorsal raphe nuclei (5-HT) and the locus
coeruleus (NA); known as the ‘off cells’
SLEEP – WAKE CYCLE
During sleep : All decrease
Corticosteroids-catecholamine- reflexes- cardiac
output peripheral BP gastric acid ,metabolic ,heart,
respiratory rates ,cerebral blood flow & brain
temprature
GH & Prolactin are secreted
During REM : Thermoregulation stops (No shivering
or sweating)=POIKILOTHERMIC CONDITION
Near paralysis of all muscles
Classification of sleep disorders
Dysomnias
1- DIMS - disorders of initiating and
maintaining sleep
a) Psychophysiological insomnia - transient and
persistent
b) DIMS associated with psychiatric disorder
c) DIMS associated with drug and alcohol abuse
d) Other conditions:
i) restless leg syndrome
2- DOES - disorders of excessive
somnolence
a) Psychophysiological DOES - transient and
persistent
b) DOES associated with psychiatric disorder
c) DOES associated with drug and alcohol
abuse
d) Sleep apnea
e) Narcolepsy
f) Idiopathic CNS Hypersomnia
g) Other medical conditions
Dysfunction associated with sleep, the sleep
stages, and partial arousals
(the Parasomnias)
a) Sleep walking
b) Night terrors
c) Sleep related enuresis
d) Dream anxiety attacks (nightmares)
e) Sleep-related epilepsy
f) Bruxism
g) Head banging (a.k.a. jacatio capitis nocturnis)
h) Body rocking
i) Sleep paralysis
j) Painful nocturnal penile erections ►
. Disorders of the sleep-wake cycle ►
a) transient - jet lag or shift work ►
b) persistent - people who frequently change their ►
cycle e.g. business men
Insomnia
► Epidemiology
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50 % lifetime prevalence
more common in:
females
the elderly
unemployed
separated
lower socioeconomic class
► Neurological
causes
► Psychiatric Illness
· 40 % have a concurrent psychiatric disorder
Restless Leg Syndrome
Deep sensation of creeping inside the calves
sitting or lying down ,not painful
Interferes with sleep and falling asleep - Peak middle age - 5% of population -
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Excessive daytime sleepiness
Aetiology :
1- Insufficient night sleep
2- Pathological causes :
-Obstructive sleep apnea
-Narcolepsy
-Drug effect
-Kleine – Levin syndrome
- Depression
Obstructive sleep apnea
2% of population – males –third are obeselate middle age
Aetiology: Airways obstructed by fatty tissues
leading to cessation of respiration many
times per night
CP : LOUD SNORING (95%) DAYTIME
SLEEPINESS(90%) unrefreshed sleep
morning headache& confusion, enuresis
Narcolepsy
· characterized by excessive sleepiness associated with REM sleep phenomena
such
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1. Cataplexy
► a) sudden temporary episodes of paralysis with muscle tone, precipitated
► by strong emotion
► b) occurs in most cases
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2. Sleep paralysis
a) a transient and generalized inability to move or speak during the
transition between sleep and wakefulness
b) typically occur while falling asleep
c) the paralysis is flaccid, and usually complete
d) episodes usually last only a few seconds, and less than one minute
3. Hypnagogic hallucinations
a) occur while falling asleep
The Kleine – Levin syndrome
-Uncommon (100 cases) affect young men
( onset in early adolescence ), self limiting ,
remission occurs spontaneously before 40
-Period of hypersomnia ( one or several weeks )
-Alternating with periods of normal sleep
Marked by withdrawal from social activities,
return to bed at first opportunity , apathy ,confusion
irritability, loss of sex inhibition, delusions , or
hallucinations.
Parasomnias
1- Abnormality of REM sleep
Nightmares
an awakening from REM sleep to full
consciousness with detailed dream recall
► · usually occur in the 1st third of nocturnal sleep
► · causes:
► · frightening experiences during the day
► · PTSD
► · fever
► · psychotropic drugs
► · alcohol detoxification
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Abnormality of nREM sleep
1- Night terror disorder
sometimes familial
► · begins and ends in childhood
► · child awakes terrified and may scream,
and usually appears confused
► · occurs in stage 3-4 sleep
► · usually occur in the 1st third of nocturnal
sleep
► · there is little or no dream recall
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2- Sleep walking (somnambulism)
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· an automatism occurring during deep non-REM sleep
(stages 3 and 4), usually in
the early part of the night
· affects 1 % of the population
· M>F
· associated with enuresis
· most common between the ages of 5 and 12 years
· 15 % of this age group sleepwalk at least once
· may be familial
· possibly due to an abnormality of deep sleep – subject
goes from deep sleep to
wakefulness
Circadian Rhythm sleep disorders
Circadian means following 24 Hours rhythm
Pacemaker of this rhythm is the
Suprachiasmatic Nucleus ( SCN)
TYPES OF DISORDERS :
Transient : jet lag or shift work
Persistent : in some jobs
The effects of drugs on sleep
Alcohol
Biphasic effect :
- In the first half of night : decrease sleep
onset latency ( promotes sleep initiation ) ,
increase deep sleep , decrease REM sleep
- In the second half : rebound increase in
REM sleep
Chronic use : disruption of all stages of sleep
Withdrawal : decrease total sleep time &
nREM sleep
Sleep and psychiatric illness
► 1.
Depression
a) reduced stage 3 and 4
b) reduced REM latency
c) REM occurs earlier in night
► 2.schizophrenia
a) reduced slow wave sleep
b) reduced REM
► 3. Anxiety
a) increased stage 1 and 2
b) reduced effecieny of sleep
► 4. Panic disorder
a) increased sleep latency
► 5.
Alcoholism
a) increased delta
b) increased REM sleep
c) increased alpha activity
► 6. Alzheimer’s disease
a) increased sleep
b) fragmentation
c) reduced sleep efficiency
Sleep and Age
As we get older :
-We have more difficulty in initiating sleep
- We awaken more often
-We take more time to fall back to sleep
-we fall asleep frequently during the day
Studying sleep is by using polysomnography
in Sleep Lab
THANK Y0U
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disturbance of sleep continuity
more time awake
increased sleep fragmentation
early morning wakening
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disturbance in the sleep architecture
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sleep deprivation (esp. deprivation of REM sleep) has a
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decreased slow wave sleep
disturbance in REM sleep
shortened REM latency
more REM activity (higher % in first ½ of the night)
higher REM density
beneficial effect on mood in depressed patients
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antidepressants destroy REM sleep - there is a rebound
of REM sleep on discontinuation