O050 Regional electromyographic activity in genioglossus during quiet breathing in supine, awake individuals with and without sleep apnoea

Abstract Introduction Inspiratory-related genioglossus electromyography (EMG) activity is crucial to maintain upper airway patency during inspiration. Recent findings suggest variations in anterior/posterior genioglossus multiunit EMG activation during awake supine quiet breathing in healthy adults. However, whether such differences extend to EMG across oblique (middle) and horizontal (base) genioglossus compartments, and whether activation differ in obstructive sleep apnoea (OSA) is unclear. Methods Prior to in-lab polysomnography, intramuscular electrodes were placed into the horizontal and oblique compartments of the genioglossus in 9 controls (AHI≤5 events/hr) and 45 age- and BMI- matched OSA patients (AHI range 5-94.3 events/hr). Multiunit EMG patterns were classified as phasic or tonic during awake supine quiet nasal breathing. Phasic pattern recordings were quantitatively analysed (% maximum of swallowing or tongue protrusion). The effects of OSA status and genioglossus compartments were assessed through mixed linear analysis, controlling for nadir Pepi and repeated measures in participants. Results More than half (57.6%, n=106/184) of the recording sites had a phasic pattern. A more negative nadir Pepi correlated with reduced likelihood of tonic activity (OR: 0.819, P=0.042). Within phasic patterns, a more negative nadir Pepi correlated with increased peak EMG (beta=-0.847, P=0.011), phasic EMG (beta=-0.654, P=0.005), and tonic EMG (beta=-0.253, P=0.048). No significant effects of OSA status or genioglossus compartment on activity patterns or EMG measurements were observed. Conclusions No compartmental disparity in EMG or differences between OSA and non-OSA individuals were found. Understanding mechanisms driving efficient dilatory activity of the genioglossus compartments is pivotal to develop OSA treatments targeting pharyngeal muscle activity.