Relationship of genioglossus muscle activation and severity of obstructive sleep apnea and hypopnea syndrome among Chinese patients

Conclusion: Variability of GGEMG at sleep onset is associated with apnea severity in OSA patients. At sleep onset, a lower decline in GGEMG might suggest a more severe OSA. Objective: The goal of this study was to evaluate genioglossus (GG) activation in the Chinese population at early sleep onset, and clarify the relationship of GG activation and the apnea severity in patients with Obstructive Sleep Apnea (OSA). Methods: Thirty-five OSA patients and 10 normal controls underwent overnight polysomnography with synchronous genioglossus electromyography (GGEMG) using intra-oral electrodes. The upper airway (UA) anatomy was evaluated by three-dimensional computer tomography (3D-CT) in all subjects. Results: The average GGEMG and tonic GGEMG were higher in the apnea patients than in the normal controls during wakefulness and early sleep onset period (three breaths) (p<0.01). Eight OSA patients had increased GGEMG at sleep onset and 27 patients had decreased GGEMG values. Between the two groups, there were significant differences in the apnea-hypopnea index (AHI), minimal cross-sectional airway area (mCAS) and minimal lateral airway dimension (mLAT) at velopharynx (p<0.05). The change in GGEMG, phasic GGEMG and tonic GGEMG from awake to sleep showed positive correlations with AHI and negative correlations with velopharynx (mLAT and mCAS) (p<0.05).