. Sleep Staging Basics /09 Sleep Staging Basics Copyright Compumedics Limited.

.Sleep Staging Basics /09

Sleep Staging Basics

Copyright Compumedics Limited


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.

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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)



Sleep Staging Channels



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



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:



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



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



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



Sleep Staging Criteria

Stage N3 - Delta Waves (≥75uV) ≥ 20% of epoch

DELTA WAVESDELTA WAVES



Sleep Staging Criteria REM

• Lowest EMG• Rapid Eye Movements (REMs)• Saw-tooth EEG• Low-amplitude, mixed frequency EEG similar

to stage 1



Stage: Awake



Stage N1 Sleep



Stage N2 Sleep



Stage N3 Sleep



Stage REM Sleep



Stage REM Sleep

Sawtooth waveform pattern seen in REM sleep.



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.



Changing Sleep Patterns With Age



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



Active Sleep - Infant



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



Quiet Sleep - Infant



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.


. Sleep Staging Basics /09 Sleep Staging Basics Copyright Compumedics Limited.

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