How is rapid eye movement (REM) sleep defined on normal sleep EEG?

Updated: May 15, 2018
  • Author: Selim R Benbadis, MD; Chief Editor: Helmi L Lutsep, MD  more...
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Answer

REM sleep normally is not seen on routine EEGs, because the normal latency to REM sleep (100 min) is well beyond the duration of routine EEG recordings (approximately 20-30 min). The appearance of REM sleep during a routine EEG is referred to as sleep-onset REM period (SOREMP) and is considered an abnormality. While not observed on routine EEG, REM sleep commonly is seen during prolonged (>24 h) EEG monitoring. Representative examples of waveforms described here can be seen in the images below.

Rapid eye movement sleep with rapid (saccadic) eye Rapid eye movement sleep with rapid (saccadic) eye movements. While muscle "atonia" cannot be proven without a dedicated electromyogram (EMG) channel, certainly EMG artifact is absent with a "quiet" recording. Also, no alpha rhythm is present that would suggest wakefulness.
Typical saccadic eye movements of rapid eye moveme Typical saccadic eye movements of rapid eye movement sleep are shown, with lateral rectus "spikes" seen just preceding the lateral abducting eye movements.
In addition to rapid eye movements, this rapid eye In addition to rapid eye movements, this rapid eye movement sleep record is characterized by brief fragments of alpha rhythm (first half) and central saw tooth waves (second half).
This is a good example of saw tooth waves seen in This is a good example of saw tooth waves seen in rapid eye movement sleep and their "notched" morphology.
This is a good example of saw tooth waves seen in This is a good example of saw tooth waves seen in rapid eye movement sleep and their "notched" morphology, best seen here in the Cz-Pz (last) channel.
This illustrates the typical appearance of saw too This illustrates the typical appearance of saw tooth waves on a polysomnogram (PSG) display, equivalent to 1 cm/s.

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