Quantification of electromyographic activity during sleep: a phasic electromyographic metric

Area of Science:

• Neuroscience
• Sleep Medicine
• Biomedical Engineering

Background:

• Electromyographic (EMG) activity is crucial for defining REM sleep and quantifying movements like PLMS.
• Routine quantification of EMG activity beyond these uses is infrequent, with a lack of normative data.
• Phasic EMG activity, though recognized, is not systematically analyzed or quantified in sleep studies.

Purpose of the Study:

• To systematically apply a visual scoring system for short-duration phasic EMG activity.
• To quantify this activity as a phasic electromyographic metric (PEM) across different muscle groups and sleep stages.
• To establish normative data for PEM in healthy subjects and compare it with patients with Parkinson's disease.

Main Methods:

• Recorded EMG activity from five muscle groups (submentalis, anterior tibialis, brachioradialis).
• Utilized a visual scoring system for short-duration (approx. 100ms) phasic EMG events.
• Quantified activity as PEM, analyzed separately for REM and non-REM sleep in young adults, older adults, and Parkinson's disease patients.

Main Results:

• PEM is a normal component of REM sleep across all recorded muscle groups.
• In healthy young adults, PEM constitutes approximately 5% of REM sleep intervals in the mentalis muscle.
• PEM occurs at higher rates in Parkinson's disease patients, with leg PEM potentially influenced by PLMS.

Conclusions:

• Phasic electromyographic metric (PEM) is a quantifiable measure of sleep motor activity.
• PEM data can be collected using digital techniques, offering a potentially valuable metric.
• PEM may be particularly relevant for identifying neurodegenerative disorders associated with motor pathway disinhibition during sleep.