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Sleep Disorders
Volume 2016, Article ID 9645347, 13 pages
Research Article

Length of Individual Apnea Events Is Increased by Supine Position and Modulated by Severity of Obstructive Sleep Apnea

1Department of Clinical Neurophysiology, Kuopio University Hospital, Puijonlaaksontie 2, 70210 Kuopio, Finland
2Department of Clinical Neurophysiology, Seinäjoki Central Hospital, Hanneksenrinne 7, 60220 Seinäjoki, Finland
3Department of Applied Physics, University of Eastern Finland, Yliopistonranta 1, 70211 Kuopio, Finland
4Institute of Clinical Medicine, Faculty of Health Sciences, University of Eastern Finland, Yliopistonranta 1, 70211 Kuopio, Finland

Received 9 December 2015; Revised 8 February 2016; Accepted 15 February 2016

Academic Editor: Giora Pillar

Copyright © 2016 Timo Leppänen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Positional obstructive sleep apnea (OSA) is common among OSA patients. In severe OSA, the obstruction events are longer in supine compared to nonsupine positions. Corresponding scientific information on mild and moderate OSA is lacking. We studied whether individual obstruction and desaturation event severity is increased in supine position in all OSA severity categories and whether the severity of individual events is linked to OSA severity categories. Polygraphic recordings of 2026 patients were retrospectively analyzed. The individual apnea, and hypopnea durations and desaturation event depth, duration, and area of 526 included patients were compared between supine and nonsupine positions in different OSA severity categories. Apnea events were 6.3%, 12.5%, and 11.1% longer () in supine compared to nonsupine position in mild, moderate, and severe OSA categories, respectively. In moderate and severe OSA categories desaturation areas were 5.7% and 25.5% larger () in supine position. In both positions the individual event severity was elevated along increasing OSA severity category (). Supine position elevates apnea duration in all and desaturation area in moderate and severe OSA severity categories. This might be more hazardous for supine OSA patients and therefore, estimation of clinical severity of OSA should incorporate also information about individual event characteristics besides AHI.