title: Asynchrony of lingual muscle recruitment during sleep in obstructive sleep apnea.
abstract: Pharyngeal collapsibility during sleep increases primarily due to decline in dilator muscle activity. However, genioglossus EMG is known to increase during apneas and hypopneas, usually without reversing upper airway obstruction or inspiratory flow limitation. The present study was undertaken to test the hypothesis that intense activation of the genioglossus fails to prevent pharyngeal obstruction during sleep, and to evaluate if sleep-induced changes in tongue muscle coordination may be responsible for this phenomenon. We compared genioglossus and tongue retractors EMG activity in 13 obstructive sleep apnea (OSA) patients during wakefulness, while breathing through inspiratory resistors, to the activity observed at the end of apneas and hypopneas after 25 mg of brotizolam, before arousal, at equal esophageal pressure. During wakefulness, resistive breathing triggered increases in both genioglossus and retractor EMG. Activation of agonist tongue muscles differed considerably from that of the arm, as both genioglossus and retractors were activated similarly during all tongue movements. During sleep, flow limitation triggered increases in genioglossal EMG that could reach more than twofold the level observed while awake. In contrast, EMGs of the retractors reached less than half the wakefulness level. In sleeping OSA patients, genioglossal activity may increase during obstructed breathing to levels that exceed substantially those required to prevent pharyngeal collapse during wakefulness. In contrast, coactivation of retractors is deficient during sleep. These findings suggest that sleep-induced alteration in tongue muscle coordination may be responsible for the failure of high genioglossal EMG activity to alleviate flow limitation.
authors: Bnai-Zion Medical Centre, Haifa, Israel;
authors: Yaniv
authors: Y
authors: Dotan
authors: Rappaport School of Medicine, Technion Israel Institute of Technology, Haifa, Israel; Carmel Medical Centre, Haifa, Israel; Sleep Laboratory, Technion, Haifa, Israel; and.
authors: Giora
authors: G
authors: Pillar
authors: Sleep Disorders Center, Johns Hopkins School of Medicine, Baltimore, Maryland.
authors: Alan R
authors: AR
authors: Schwartz
authors: Bnai-Zion Medical Centre, Haifa, Israel; Rappaport School of Medicine, Technion Israel Institute of Technology, Haifa, Israel; oliven@tx.technion.ac.il.
authors: Arie
authors: A
authors: Oliven
mesh_terms: D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000187:drug effects; D001132:Arm / Q000502:physiology; D001381:Azepines / Q000494:pharmacology; D004576:Electromyography; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000503:physiopathology*; D010609:Pharyngeal Muscles / Q000503:physiopathology; D017286:Polysomnography; D011999:Recruitment, Neurophysiological / Q000187:drug effects; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D014059:Tongue / Q000187:drug effects / Q000503:physiopathology*; D014851:Wakefulness
chemical_list: D001381:Azepines; D006993:Hypnotics and Sedatives; C020960:brotizolam
keywords: control of breathing; genioglossus; obstructive sleep apnea; tongue retractors; upper airway