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Sleep Staging Basics
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The following presentation is being provided for informational and educational purposes only.  While Compumedics endeavors to ensure the validity and accuracy of the information within, we cannot be held responsible for inaccuracies, opinions or practices that often vary between various experts or are without established acceptable medical standards.  Please consult your own medical director for clarification or for policies that are specific to your facility. 
We welcome your comments, suggestions and corrections.  Please
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3. Sleep Staging Variables
Electroencephalogram (EEG) - acquired by surface electrodes on the scalp at standardized locations (10-20 system)
Electrooculogram (EOG) - acquired by surface electrodes placed at the outer canthus of each eye
Electromyogram (EMG) - acquired by surface electrodes placed on the chin muscle (sub-mental)
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4. Sleep Staging Channels
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EEG
Frequency and amplitude change with sleep stage:
Wake: high frequency
Stage N1and REM: low amplitude, mixed frequency (vertex waves may be in N1)
Stage N2: spindles, k-complexes
Stage N3: delta waves (≥ 75 uV, ≤ 2 Hz)
Standard sleep epoch is 30 seconds
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EOG
EOG records voltage changes caused by eye movement; EOG changes with sleep stage
Wake: random, high amplitude:
Stage 1: slow rolling:
REM: very flat with occasional rapid eye movements:
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EMG
Recorded as the potential between two surface electrodes placed several centimeters apart
Typically, the chin (submental) muscle is used because it exhibits large differences during sleep, aiding in the identification of stages
Wake - high activity
Sleep - lower activity
REM sleep - paralysis of skeletal muscles
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Sleep Stage Criteria
ALPHA WAVES
Awake
Alpha or faster > 50% of epoch
Many eye movements
High EMG
Stage N1
Alpha or faster < 50 % of epoch
Increasing theta activity
Slow rolling eyes
Vertex sharp waves
THETA WAVES
VERTEX WAVE
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9. Sleep Staging Criteria
Stage N2
Sleep Spindles
12-14 cps
0.5 second duration or longer
and/or
K-complexes
Sharp negative deflection followed by nearly equal positive deflection
At least 0.5 seconds in duration
Sleep Spindle
K-complex
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10. Sleep Staging Criteria
Stage N3 - Delta Waves (≥75uV) ≥ 20% of epoch
DELTA WAVES
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11. Sleep Staging Criteria
REM
Lowest EMG
Rapid Eye Movements (REMs)
Saw-tooth EEG
Low-amplitude, mixed frequency EEG similar to stage 1
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Stage: Awake
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Stage N1 Sleep
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Stage N2 Sleep
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Stage N3 Sleep
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Stage REM Sleep
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Stage REM Sleep
Sawtooth waveform pattern seen in REM sleep.
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Infant Sleep Patterns
Circadian rhythm not established prior to week 10 or 11 from birth.
Consolidation of sleep usually occurs by week
Between weeks Active-Quiet Sleep pattern is established.
At 5-6 months R&K rules can be applied.
Age is corrected for normal gestational age.
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19. Changing Sleep Patterns With Age
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Active Sleep - Infant
Continuous cycling of wakefulness-active sleep (REM) and quiet sleep(NREM).
Sleep onset is usually to active sleep (REM)
Mixed, low-voltage, irregular EEG
Suppressed EMG
Intermittent REMs
Frequent muscle twitches and body movements
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Active Sleep - Infant
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Quiet Sleep - Infant
High voltage, slow-wave EEG activity
Trace alternant, 3-8 sec. burst of high voltage slow waves, alternating with 4-8 seconds of low voltage mixed freq. waves
EMG tonic
Eye movements absent
Minimal body movement
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Quiet Sleep - Infant
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Infant Sleep Staging
Wake, Active (REM) Sleep, Quiet (NREM) Sleep, Indeterminate, Movement or Artifact.
If an epoch can not be staged as Wake, Active or Quiet, it is Indeterminate.
Crying is considered awake.
Artifact is scored if one minute or more of recording is unscorable.
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