SLEEP STAGE SCORING
BY
Prof . Mohammad El –Desouky Abou-Shehata
Prof. Of Thoracic Medicine
Sleep Medicine Unite
Mansoura University
Sleep
Objectives
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Definition and Historical pre
Sleep stages
Sleep architecture
History Of Sleep
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In Greek mythology,sleep was considered a state similar to death
and as such, the goddess of night, Nxy was portrayed as the
mother of both god of sleep, hypnos ,and the god of
death,Thanatos
,Aristotle recognised sleep was characterised by relative
inattention to the environment an physical immobility and
suggested that sleep reflected the time needed to replinish
“Power” lost from systems involved in sensory perception during
wakefulness
Sleep was originally considered a time of brain inactivity
it is now recognised, however,that sleep is an extremely active
process as evidenced by a highly predictable change in brain
electrical activity.muscle,activity,and autonomic control
‫بسم هللا الرحمن الرحيم‬
‫‪ ‬ه‬
‫ين َم ْوت َها َوالهتي َل ْم َتم ْ‬
‫ُت‬
‫سح َ‬
‫َّللاُ َي َت َو هفى األَنفُ َ‬
‫ضى َع َل ْي َها ْال َم ْو َ‬
‫ت‬
‫في َم َنام َها َف ُيمْس ُ‬
‫ك الهتي َق َ‬
‫ك‬
‫َويُرْ س ُل األ ُ ْخ َرى إ َلى أَ َجل ُم َس ًّمى إنه في َذل َ‬
‫آل َيات لِّ َق ْوم َي َت َف هكرُو َن ‪‬‬
‫سورة الزمر ايه ‪42‬‬
Definition Of Sleep
Sleep is a naturally recurring state characterized
by reduced or lacking consciousness, relatively
suspended sensory activity, and inactivity of
nearly all voluntary muscles.It is distinguished
from quiet wakefulness by a decreased ability to
react to stimuli, but it is more easily reversible
than hibernation or coma
Historical Prespectives of Sleep Staging
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IN 1937 Loomis and colleagues noted fragmentation and fallout of alpha rhythm
with sleep onset, and subsequent onset of sleep spindles, K complexes and high amplitude
slow waves. Sleep was divided into 5 stages (A-E), with later stages possessing more
slow-frequency and high-amplitude waves.
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In 1957 Kleitman and Dement :The discovery of rapid eye movement (REM) sleep
led to a classification of sleep stages that included REM sleep.
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In 1968, Rechtschaffen and Kales standardized manual for the scoring of sleep
stages.
- Sleep stages were divided into wakefulness, stage 1-4 (non-REM), or REM
- At least 1 EEG lead was recommended (C3 or C4 referenced to the opposite
ear or mastoid)
- 2 electro-oculogram (EOG) leads and a submental electromyography lead.
- The R and K rules recommended dividing the polysomnographic record of
sleep into 30 second epochs, commencing at the start of the study
In 2004,(AASM): Introduced new sleep scoring manual that would address sleep staging as well
as the scoring of arousals, respiratory, cardiac, and movement events
Why We SLEEP ?
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Sleep is necessary for survival.
In animal studies : The normal life span of rats is 2-3
years. However, rats deprived of sleep live for only
about 3 weeks.
They also develop abnormally low body
temperatures and sores on their tails and paws
The sores probably develop because of impairment
of the rats’ immune systems.
Sleep Importance
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IN human studies SLLEEP DEPRIVATION
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metabolic activity of the brain decreases significantly after 24 hours of
sustained wakefulness.
a decrease in immune system function as measured by white blood
cell count
impairment of memory and physical performance and reduced ability
to carry out mathematical calculations
Release of growth hormone in children and young adults takes place
during deep sleep
Sleep deprivation can also cause increased heart rate variability
Most cells of the body show increased production and reduced
breakdown of proteins during deep sleep
maintain optimal emotional and social functioning while we are awake.
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Normative Sleep Stage Data
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Normative values have been constructed based on
sleep staging results to help quantify the composition
and quality of sleep.
Normative data change with age and vary from
center to center.
In addition, most were collected using the R and K
rules.
Sleep Stage Nomenclature
R&K
Wake
NREM
REM
Stage W
Stage 1
Stage 2
Stage 3
Stage 4
Stage REM
AASM
Stage W
N1
N2
N3
Stage R
AASM = American Academy of Sleep Medicine2; NREM = non–rapid eye movement;
R&K = Rechtschaffen and Kales A1; REM = rapid eye movement; stages 3 and 4 are
combined into stage N3.
Electroencephalographic Electrode Nomenclature
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Frontopolar
Frontal
Central
Occipital
Mastoid
LEFT
Fp1
F3
C3
O1
M1
RIGHT
Fp2
F4
C4
O2
M2
MIDLINE
Fpz
Fz
Cz
Oz
Sleep Cycle
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A complete sleep cycle, from the beginning of stage I
to the end of REM sleep, usually takes about one
and a half hours.
REM sleep represents 20-25% of the total sleep
time. REM sleep follows NREM sleep and occurs 4-5
times during a normal 8- to 9-hour sleep period.
The first REM period of the night may be less than
10 minutes in duration, while the last may exceed 60
minutes.
In a normal night’s sleep, bouts of REM occur every
90 minutes.
Sleep cycle
A complete cycle lasts around 90 to 110 minutes. So eight hours of
sleep will give you around five of these sleep cycles per night
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Sleep Stage Scoring
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Electroencephalography EEG
Electro-oculography
EOG
Electromyography
EMG
Cortical Signals
Electrocephalic Waves
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Delta is the slowest activity at <4 cycles per second (cps).
Theta is 4-8 cps.
Alpha is 8-13 cps.
Beta is >13 cps
Characteristic of Alpha Rhythm and Sleep Spindles
Characteristic of K complex and slow wave activity
K complex associated with arousal
EOC – K complex in-phase –REM out-phase
Eye Movement Pattern
Sleep Stage Scoring
SCORING BY EPOCHS
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The AASM scoring manual continues the convention of staging
sleep in sequential 30-second epochs.
Each epoch is assigned a sleep stage. If two or more stages
coexist during a single epoch, the epoch is assigned the stage
comprising the greatest portion of the epoch.
Wake Stage
AASM RULE
Epochs
Stage N1 Scoring
Stage N1
Stage N2 Scoring
Stage 2 scoring
Stage N2
Stage N3 Scoring
Stage N3 Rules
A. Score stage N3 when 20% or more of an epoch
consists of SWA, irrespective of age (20% of 30-sec epoch
= 6 sec).
1. EEG: SWA ≥ 20% of the epoch (≥6 sec), sleep spindles
may be present in stage N3.
2. EOG: Eye movements are not typically seen during
stage N3 sleep.
3. EMG: In stage N3, the chin EMG is of variable amplitude,
often lower than in stage N2 sleep and sometimes as low as
in stage R sleep.
Stage N3 sleep (30-sec epoch). The dotted lines in F4-M1 are 75 μV apart. The
grid lines are 1 second apart. Slow wave activity is present in all 30 seconds
of the epoch
Stage R
Stage R
 A low – amplitude EEG without KCs or SSs
 REMS
 Low EMG tone
- These three component of stage R may not all start or stop at the
same time
- Not all epochs of stage R have REMS
- Therefore, special rules are needed fore the start, contnuation and
end of sage R as well as transition from N2 to REM stage
Stage - R
Stage -R
Continuation of stage R:
Continue to score stage R
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Sleep, even in the absence of
REMs, for epochs following
one or more epochs of stage R
if
a. EEG continues to show lowamplitude mixed-frequency
activity without K complexes or
sleep spindles.
b. Chin EMG: Tone remains low
(at REM level).
End of Stage R
End of Stage R ( transition to stage W or N3
End of REM sleep : increase in chin EMG activity
Stage R Interrupted by arousal
End Stage R by transition to N2
Transition from definite N2 to R•
Transition from stage N2 to R
Interruption of Stage R by K complex
Stage N1 is scored after an arousal during stage N2 sleep.
MAJOR BODY MOVEMENTS
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An MBM is defined as movement and muscle
artifact obscuring the EEG for more than half
an epoch to the extent that sleep stage
cannot be determined
Scoring Major Body Movement
Arousals
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Arousals are transient phenomenon that may lead to
wakefulness or only briefly interrupt sleep.
They are worth scoring because patients with frequent
arousals may have daytime sleepiness even if the total
sleep duration is normal.
An arousal is scored during sleep stages N1, N2, and
N3 (NREM sleep) if there is an abrupt shift of EEG
frequency including alpha, theta, and/or frequencies
greater than 16 Hz (but not spindles) that lasts at least
3 seconds, with at least 10 seconds of stable sleep
preceding the change
Arousal Rules
An Epoch shows -------? ?
An Epoch Shows ------- ? ?
An Epoch Shows-----? ?
Sleep Architecture
Normative Sleep Stage Data Across Age Groups.*
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Age (y)
20-29 30-39 40-49 50-59 >60
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TST (min)
374.9
375.8 370.2 3666
348.8
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Sleep Efficiency (%)
94.4
94.4
90.2
90.4
85.8
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Sleep Latency (min)
6.3
10.0
8.4
6.1
8.2
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Number of Awakenings
6.3
4.7
8.4
9.7
12.3
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Stage R (%TIB)
22.2
23.1
20.4
20.9
16.4
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Stage N1 (%TIB)
3.0
2.5
4.3
4.7
4.0
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Stage N2 (%TIB)
50.5
52.8
54.6
56.7
57.6
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Stage N3 (%TIB)
18.8
16.1
10.9
8.1
7.7
Sleep Architecture
Delta Power
REM Latency
Typical hypnograms for children, young adults, and elderly
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Note that in all three cases, the
majority of deep, slow-wave sleep
occurs during the first half of the
night, and the majority of REM
sleep occurs in the latter half of the
night.
Elderly sleep is shallow and
fragmented—it exhibits less slowwave sleep, shorter REM periods,
and more frequent periods of wake.
Children have a long, restorative
period of delta sleep during the first
sleep cycle, and another early in
the morning.
Current thinking is that the shallow
fragmented sleep of the elderly is
more a function of other health
problems than a sleep problem per
se. Elderly persons in excellent
health do not exhibit shallow,
fragmented sleep. Those with
multiple health problems, do.
Thank you