Which channel is used to monitor muscle tone in a standard polysomnography recording?

Which channel is used to monitor muscle tone in a standard polysomnography recording?

• A. EEG
• B. EMG
• C. EOG
• D. DC

Answer: (B)

The muscle tone is monitored with electromyography, typically the submental (chin) EMG channel. This channel records activity from facial and neck muscles, which is high when awake, decreases through non-REM sleep, and becomes minimal during REM sleep (atonia) with only occasional twitches. This pattern is essential for distinguishing REM from other stages, since EEG and EOG reflect brain activity and eye movements, not muscle tone. The DC channel isn’t used to track muscle tone in standard sleep studies, so EMG is the appropriate choice for monitoring muscle tone.

The muscle tone is monitored with electromyography, typically the submental (chin) EMG channel. This channel records activity from facial and neck muscles, which is high when awake, decreases through non-REM sleep, and becomes minimal during REM sleep (atonia) with only occasional twitches. This pattern is essential for distinguishing REM from other stages, since EEG and EOG reflect brain activity and eye movements, not muscle tone. The DC channel isn’t used to track muscle tone in standard sleep studies, so EMG is the appropriate choice for monitoring muscle tone.