Alae nasi electromyographic activity and timing in obstructive sleep apnea

Area of Science:

• Respiratory Physiology
• Sleep Medicine
• Neuromuscular Function

Background:

• The alae nasi muscles are upper airway dilators in the nose.
• Their role during obstructive sleep apnea (OSA) is not fully understood.
• Understanding alae nasi function can offer insights into airway stability during sleep.

Purpose of the Study:

• To investigate the relationship between alae nasi muscle activity and respiratory muscle effort during obstructive apneas.
• To determine the timing of alae nasi activation relative to rib cage and diaphragm contraction.
• To compare these relationships during different sleep stages (NREM and REM).

Main Methods:

• Electromyograms (EMG) of the alae nasi were recorded using surface electrodes in nine patients with OSA.
• EMG signals were processed to obtain a moving time average.
• Rib cage and diaphragm contractions were assessed via changes in esophageal pressure.

Main Results:

• A significant correlation was found between alae nasi EMG activity and esophageal pressure changes during non-rapid-eye-movement (NREM) sleep.
• Correlations were significantly lower during rapid-eye-movement (REM) sleep.
• Alae nasi activation occurred progressively earlier relative to esophageal pressure changes as apnea duration increased.

Conclusions:

• Alae nasi muscle activity increases in conjunction with diaphragm and rib cage muscle force during obstructive apneas in NREM sleep.
• The timing of alae nasi activation advances as apneic episodes progress.
• These findings highlight the alae nasi's role in upper airway dilator function during OSA events.