Abstract
Background: In OSA genioglossus (GG) EMG may increase during flow-limitation (IFL) without restoring pharyngeal patency. In comparison, retractors activation is diminished during sleep.
Goal: To compare the mode of recruitment of multiple dilator muscles during IFL in OSA and healthy subjects.
Methods: Esophageal pressure (Pes), airflow and EMG of the GG, styloglossus, geniohyoid, sternocleidomastoid and sternohyoid (3 EMGs/subject) were recorded in 6 OSA patients and 8 healthy subjects. EMG/Pes wasassessed when the subjects breathed through a variable resistor. During sleep, EMG/Pes was evaluated during IFL. Pre-arousal sleepEMG was compared to awakeEMG at the same Pes.
Results: During resistive breathing (wakefulness), activity of all muscles increased. During IFL GG-EMG was much larger than during wakefulness (SleepEMG/awakeEMG ratio 3.1±1.3 and 2.6±1.0 for OSA and healthy subjects). The ratio for the other dilator muscles was <1.
Conclusions:
1. During sleep GG activity may increase during IFL more than during wakefulness. Other peri- pharyngeal muscles' activity is diminished.
2. This alteration occurs both in health and OSA. It may disrupt dilator muscle coordination, thereby preventing restitution of pharyngeal patency even when the GG is highly active.
- Copyright ©the authors 2016
