[Dilator naris activity in relation to obstructive sleep apnea].

Area of Science:

• Neurology
• Sleep Medicine
• Respiratory Physiology

Context:

• Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent airway collapse during sleep.
• Understanding the neuromuscular control of the upper airway is crucial for OSAS pathophysiology.
• Electromyography (EMG) provides insights into muscle activity during sleep.

Purpose:

• To investigate the periodic changes in dilator nasalis and submental muscle EMG activity during sleep in OSAS patients.
• To correlate these EMG changes with the occurrence of apnea and hypopnea episodes.
• To compare the influence of sleep stages (REM vs. non-REM) and airway obstruction severity on muscle activity.

Summary:

• Periodic changes in dilator nasalis+ EMG and submental EMG were observed during sleep in three OSAS patients, showing a strong correlation (r = 0.85).
• Apnea and hypopnea episodes consistently occurred at the lowest points (nadir) of these periodic EMG activities.
• Muscle activity at the nadir was significantly lower during Rapid Eye Movement (REM) sleep compared to non-REM sleep, and further reduced during severe airway obstruction with paradoxical thoracic/abdominal movements.
• Submental EMG showed a stronger correlation with SaO2 and apnea duration than dilator nasalis+ EMG.

Impact:

• This study highlights the role of specific upper airway muscles in the dynamic changes associated with OSAS.
• Findings suggest that reduced dilator nasalis and submental muscle activity may contribute to airway collapse during sleep.
• The differential correlation with submental EMG provides potential for improved monitoring or therapeutic targets in OSAS management.