Upper airway neuromuscular compensation during sleep is defective in obstructive sleep apnea

Brian M. McGinley, Alan R. Schwartz, Hartmut Schneider, Jason P. Kirkness, Philip L. Smith, Susheel P. Patil

Research output: Contribution to journalArticle

Abstract

Obstructive sleep apnea is the result of repeated episodes of upper airway obstruction during sleep. Recent evidence indicates that alterations in upper airway anatomy and disturbances in neuromuscular control both play a role in the pathogenesis of obstructive sleep apnea. We hypothesized that subjects without sleep apnea are more capable of mounting vigorous neuromuscular responses to upper airway obstruction than subjects with sleep apnea. To address this hypothesis we lowered nasal pressure to induce upper airway obstruction to the verge of periodic obstructive hypopneas (cycling threshold). Ten patients with obstructive sleep apnea and nine weight-, age-, and sex-matched controls were studied during sleep. Responses in genioglossal electromyography (EMG GG) activity (tonic, peak phasic, and phasic EMGGG), maximal inspiratory airflow (VImax), and pharyngeal transmural pressure (PTM) were assessed during similar degrees of sustained conditions of upper airway obstruction and compared with those obtained at a similar nasal pressure under transient conditions. Control compared with sleep apnea subjects demonstrated greater EMGG, VImax, and PTM responses at comparable levels of mechanical and ventilatory stimuli at the cycling threshold, during sustained compared with transient periods of upper airway obstruction. Furthermore, the increases in EMG GG activity in control compared with sleep apnea subjects were observed in the tonic but not the phasic component of the EMG response. We conclude that sustained periods of upper airway obstruction induce greater increases in tonic EMGGG, VImax, and PTM in control subjects. Our findings suggest that neuromuscular responses protect individuals without sleep apnea from developing upper airway obstruction during sleep.

Original languageEnglish (US)
Pages (from-to)197-205
Number of pages9
JournalJournal of applied physiology
Volume105
Issue number1
DOIs
StatePublished - Jul 2008

Keywords

  • Neuromuscular responses
  • Upper airway neuromuscular control

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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