Effect of coactivation of tongue protrusor and retractor muscles on pharyngeal lumen and airflow in sleep apnea patients

Arie Oliven, Majed Odeh, Louis Geitini, Ron Oliven, Uri Steinfeld, Alan R. Schwartz, Nave Tov

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


The present study evaluated the effect of coactivation of tongue protrusors and retractors on pharyngeal patency in patients with obstructive sleep apnea. The effect of genioglossus (GG), hyoglossus (HG), and coactivation of both on nasal pressure (Pn):flow relationships was evaluated in a sleep study (SlS, n = 7) and during a propofol anesthesia study (AnS, n = 7). GG was stimulated with sublingual surface electrodes in SlS and with intramuscular electrodes in AnS, while HG was stimulated with surface electrodes in both groups. In the AnS, the cross-sectional area (CSA):Pn relationships was measured with a pharyngoscope to estimate velopharyngeal compliance . In the SlS, surface stimulation of GG had no effect on the critical pressure (Pcrit), HG increased Pcrit from 2.8 ± 1.7 to 3.7 ± 1.6 cmH2O, but coactivation lowered Pcrit to 0.2 ± 1.9 cmH2O (P < 0.01 for both). In the AnS, intramuscular stimulation of GG lowered Pcrit from 2.6 ± 1.3 to 1.0 ± 2.8 cmH2O, HG increased Pcrit to 6.2 ± 2.5 cmH2O (P < 0.01), and coactivation had a similar effect to that of GG (Pcrit = 1.2 ± 2.4 cmH2O, P < 0.05). None of the interventions affected significantly velopharyngeal compliance. We conclude that the beneficial effect of coactivation depends on the pattern of GG fiber recruitment: although surface stimulation of GG failed to protrude the tongue, it prevented the occlusive effect of the retractor, thereby improving pharyngeal patency during coactivation. Stimulation of deeper GG fibers with intramuscular electrodes enlarged the pharynx, and coactivation had no additive effect.

Original languageEnglish (US)
Pages (from-to)1662-1668
Number of pages7
JournalJournal of applied physiology
Issue number5
StatePublished - Nov 2007
Externally publishedYes


  • Genioglossus
  • Hyoglossus
  • Pharynx
  • Sleep apnea
  • Tongue muscles

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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