title: Nonrapid Eye Movement-Predominant Obstructive Sleep Apnea: Detection and Mechanism.
abstract: OBJECTIVE
  Obstructive sleep apnea (OSA) can be severe and present in higher numbers during rapid eye movement (REM) than nonrapid eye movement (NREM) sleep; however, OSA occurs in NREM sleep and can be predominant. In general, ventilation decreases an average 10% to 15% during transition from wakefulness to sleep, and there is variability in just how much ventilation decreases. As dynamic changes in ventilation contribute to irregular breathing and breathing during NREM sleep is mainly under chemical control, our hypothesis is that patients with a more pronounced reduction in ventilation during the transition from wakefulness to NREM sleep will have NREM- predominant rather than REM-predominant OSA.
  
  
  METHODS
  A retrospective analysis of 451 consecutive patients (apnea-hypopnea index [AHI] > 5) undergoing diagnostic polysomnography was performed, and breath-to-breath analysis of the respiratory cycle duration, tidal volume, and estimated minute ventilation before and after sleep onset were examined. Values were calculated using respiratory inductance plethysmography. The correlation between the percent change in estimated minute ventilation during wake-sleep transitions and the percentage of apnea-hypopneas in NREM sleep (%AHI in NREM; defined as (AHI-NREM) / [(AHI-NREM) + (AHI-REM)] × 100) was the primary outcome.
  
  
  RESULTS
  The decrease in estimated minute ventilation during wake-sleep transitions was 15.0 ± 16.6% (mean ± standard deviation), due to a decrease in relative tidal volume. This decrease in estimated minute ventilation was significantly correlated with %AHI in NREM (r = -0.222, p < 0.01).
  
  
  CONCLUSIONS
  A greater dynamic reduction in ventilation back and forth from wakefulness to sleep contributes to the NREM predominant OSA phenotype via induced ventilatory instability.
authors.affiliation: Second Department of Internal Medicine (Department of Respiratory Medicine), Nara Medical University, Kashihara, Japan.
authors.forename: Motoo
authors.initials: M
authors.lastname: Yamauchi
authors.affiliation: Second Department of Internal Medicine (Department of Respiratory Medicine), Nara Medical University, Kashihara, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Fujita
authors.affiliation: Second Department of Internal Medicine (Department of Respiratory Medicine), Nara Medical University, Kashihara, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Kumamoto
authors.affiliation: Second Department of Internal Medicine (Department of Respiratory Medicine), Nara Medical University, Kashihara, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Yoshikawa
authors.affiliation: Center for Sleep Disorders, Tenri City Hospital, Tenri, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ohnishi
authors.affiliation: Department of Pulmonology, Fukuoka National Hospital, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakano
authors.affiliation: Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University and Louis Stokes Cleveland VA Medical Center, Cleveland, OH.
authors.forename: Kingman P
authors.initials: KP
authors.lastname: Strohl
authors.affiliation: Second Department of Internal Medicine (Department of Respiratory Medicine), Nara Medical University, Kashihara, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kimura
mesh_terms: D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000706:statistics & numerical data; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology*; D012895:Sleep, REM
keywords: NREM-predominant OSA; obstructive sleep apnea; respiratory physiology during sleep
references.citation: Chest. 2005 Nov;128(5):3350-7
references.pmid: 16304283
references.citation: Am J Respir Crit Care Med. 2004 Dec 1;170(11):1225-32
references.pmid: 15317668
references.citation: Sleep Breath. 2008 Aug;12(3):259-64
references.pmid: 18074161
references.citation: Respir Physiol Neurobiol. 2008 Jul 31;162(2):144-51
references.pmid: 18577470
references.citation: Chest. 2008 Dec;134(6):1156-61
references.pmid: 18812455
references.citation: Am J Respir Crit Care Med. 2010 Jan 15;181(2):189-93
references.pmid: 19762565
references.citation: Clin Sci (Lond). 2011 Jun;120(12):505-14
references.pmid: 21269278
references.citation: J Appl Physiol (1985). 2011 Jun;110(6):1627-37
references.pmid: 21436459
references.citation: Chest. 2011 Jul;140(1):54-61
references.pmid: 21393396
references.citation: J Physiol. 2012 Mar 1;590(5):1199-211
references.pmid: 22219335
references.citation: J Appl Physiol (1985). 2013 Apr;114(7):911-22
references.pmid: 23349453
references.citation: Sleep Breath. 2013 May;17(2):845-52
references.pmid: 23080481
references.citation: Am J Respir Crit Care Med. 2014 Oct 15;190(8):930-7
references.pmid: 25191791
references.citation: IEEE Trans Biomed Eng. 2002 Mar;49(3):206-16
references.pmid: 11878312
references.citation: Am J Respir Crit Care Med. 2001 Apr;163(5):1181-90
references.pmid: 11316657
references.citation: Eur Respir J. 2015 Feb;45(2):408-18
references.pmid: 25323235
references.citation: Sleep. 2004 Mar 15;27(2):229-34
references.pmid: 15124715
references.citation: Am Rev Respir Dis. 1978 Nov;118(5):909-39
references.pmid: 216294
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1981 Apr;50(4):724-30
references.pmid: 6790487
references.citation: Thorax. 1982 Nov;37(11):840-4
references.pmid: 7164002
references.citation: Clin Sci (Lond). 1984 Nov;67(5):465-71
references.pmid: 6383691
references.citation: Am J Respir Crit Care Med. 1998 Oct;158(4):1142-9
references.pmid: 9769273
references.citation: J Clin Sleep Med. 2007 Mar 15;3(2):169-200
references.pmid: 17557426