sleep staging basics /09 sleep staging basics copyright compumedics limited
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.Sleep Staging Basics /09
Sleep Staging Basics
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.Sleep Staging Basics /09
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 e-mail your comments to: [email protected]
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.Sleep Staging Basics /09
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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Sleep Staging Channels
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.Sleep Staging Basics /09
EEGFrequency 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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.Sleep Staging Basics /09
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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.Sleep Staging Basics /09
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
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
ALPHA WAVESALPHA WAVES
THETA WAVESTHETA WAVES
VERTEX WAVEVERTEX WAVE
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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 SpindleSleep Spindle
K-complexK-complex
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Sleep Staging Criteria
Stage N3 - Delta Waves (≥75uV) ≥ 20% of epoch
DELTA WAVESDELTA WAVES
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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 16-17. Between 24-36 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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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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