Chest
Volume 135, Issue 4, April 2009, Pages 957-964
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Original Research
Sleep Medicine
The Influence of Obstructive Sleep Apnea and Gender on Genioglossus Activity During Rapid Eye Movement Sleep

https://doi.org/10.1378/chest.08-2292Get rights and content

Background

The mechanisms contributing to worsening of obstructive sleep apnea (OSA) during rapid eye movement (REM) sleep have been minimally studied. Reduced upper-airway muscle tone may be an important contributor. Because respiratory events and the associated blood gas changes can influence genioglossus (GG) activity, we compared GG activity between OSA patients and control subjects during REM sleep using continuous positive airway pressure (CPAP) to minimize the influences of upper-airway resistance (RUA) and blood gas disturbances on GG activity.

Methods

Twenty subjects (10 female subjects), 12 healthy individuals, and 8 OSA patients, were studied overnight. Sleep staging, epiglottic pressure, minute ventilation, and GG electromyogram (GGEMG) were recorded. GGEMG was compared between REM sleep with (phasic REM) and without (tonic REM) eye movements, non-REM (NREM) sleep, and wakefulness.

Results

Breathing frequency increased from stable NREM, to tonic REM to phasic REM sleep, whereas tidal volume and GGEMG decreased (ie, peak GGEMG: 3.0 ± 0.7 vs 1.7 ± 0.4 vs 1.2 ± 0.3% max, respectively; p < 0.001). Reductions in GGEMG during REM sleep were not different between OSA patients and control subjects or between genders.

Conclusions

When RUA and blood gas disturbances are minimized by CPAP, genioglossal activity is reduced in a stepwise manner from stable NREM, to tonic REM to phasic REM sleep to a similar extent in OSA and healthy individuals of both genders. Thus, an inherent abnormality in GG neural control in OSA patients during REM sleep is unlikely to explain the increased upper-airway collapse in this sleep stage. Rather, a generalized reduction in GG activity during REM likely renders individuals who are highly reliant on upper-airway dilator muscles vulnerable to pharyngeal collapse during REM sleep.

Section snippets

Subjects

Periods of wakefulness and stable NREM and REM sleep were identified (see data analysis section for further detail) in 20 subjects (10 women). Although some of our subjects participated in a prior experiment,15 none of the findings of the present study have been previously reported. Eight subjects (four women) had OSA and reported nightly use of CPAP for at least 3 months before participation in the study. The remaining subjects were healthy individuals (six women) without reported history of

Anthropometric Characteristics

The mean age and the body mass index of the 20 subjects were 42 ± 3 years and 29 ± 2 kg/m2, respectively. Male and female participants did not differ in age (40 ± 3 vs 44 ± 4 years, respectively; p = 0.452) or body mass index (29 ± 2 vs 29 ± 2 kg/m2, respectively; p = 0.879). OSA patients had severe disease with an apnea-hypopnea index of 51 ± 10 events per hour (range, 13 to 94 events per hour). OSA patients were older (48 ± 3 vs 37 ± 3 years, respectively; p = 0.047) and had higher body mass

Discussion

The main finding of this study was that phasic and tonic GGEMG activity decreased considerably from wakefulness to stable NREM to REM sleep in both healthy subjects and patients with OSA on CPAP. The presence of eye movements during REM sleep was associated with further decrements in peak GGEMG activity. These data are in concordance with the few previous studies in this area, but they extend these prior observations by fully characterizing the extent of these reductions and determining that

References (50)

  • C O'Connor et al.

    Gender differences in the polysomnographic features of obstructive sleep apnea

    Am J Respir Crit Care Med

    (2000)
  • DP White

    Pathogenesis of obstructive and central sleep apnea

    Am J Respir Crit Care Med

    (2005)
  • L Wiegand et al.

    Changes in upper airway muscle activation and ventilation during phasic REM sleep in normal men

    J Appl Physiol

    (1991)
  • YL Lo et al.

    Genioglossal muscle response to CO2 stimulation during NREM sleep

    Sleep

    (2006)
  • E Onal et al.

    Diaphragmatic and genioglossal electromyogram responses to isocapnic hypoxia in humans

    Am Rev Respir Dis

    (1981)
  • E Onal et al.

    Diaphragmatic and genioglossal electromyogram responses to CO2 rebreathing in humans

    J Appl Physiol

    (1981)
  • ML Stanchina et al.

    Genioglossus muscle responsiveness to chemical and mechanical stimuli during non-rapid eye movement sleep

    Am J Respir Crit Care Med

    (2002)
  • ES Katz et al.

    Genioglossus activity during sleep in normal control subjects and children with obstructive sleep apnea

    Am J Respir Crit Care Med

    (2004)
  • AR Schwartz et al.

    The hypotonic upper airway in obstructive sleep apnea: role of structures and neuromuscular activity

    Am J Respir Crit Care Med

    (1998)
  • AS Jordan et al.

    Mechanisms used to restore ventilation after partial upper airway collapse during sleep in humans

    Thorax

    (2007)
  • JA Rowley et al.

    The effect of rapid eye movement (REM) sleep on upper airway mechanics in normal human subjects

    J Physiol

    (1998)
  • J Ludbrook

    On making multiple comparisons in clinical and experimental pharmacology and physiology

    Clin Exp Pharmacol Physiol

    (1991)
  • WS Mezzanotte et al.

    Influence of sleep onset on upper-airway muscle activity in apnea patients versus normal controls

    Am J Respir Crit Care Med

    (1996)
  • C Worsnop et al.

    Activity of respiratory pump and upper airway muscles during sleep onset

    J Appl Physiol

    (1998)
  • DJ Tangel et al.

    Influences of NREM sleep on the activity of tonic vs. inspiratory phasic muscles in normal men

    J Appl Physiol

    (1992)
  • Cited by (0)

    This study was supported by National Institutes of Health grants P50 HL60292, R01 HL085188-01, RO1-HL73146, AG024837-01, and RR01032; and by American Heart Association grants 0635318N and 0840159N. Dr. Eckert is supported by the Thoracic Society of Australia and New Zealand/Allen and Hanbury's Respiratory Research Fellowship.

    Dr. Malhotra has received consulting and/or research income from Respironics, Restore/Medtronic, NMT Medical, Apnex Medical, Itamar Medical, Pfizer, Cephalon, and Inspiration Medical. Dr. White is Chief Medical Officer for Respironics Inc. Drs. Eckert, Lo, and Jordan have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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