Hypersomnolence, insomnia and the pathophysiology of upper airway resistance syndrome

Gold, Avram R.; Gold, Morris S.; Harris, Keith W.; Espeleta, Vidal J.; Amin, Mohammad M.; Broderick, Joan E.

doi:10.1016/j.sleep.2007.08.013

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Volume 9, Issue 6 , Pages 675-683, August 2008

Hypersomnolence, insomnia and the pathophysiology of upper airway resistance syndrome

Avram R. Gold
- Division of Pulmonary/Critical Care Medicine, Stony Brook University School of Medicine, Stony Brook, DVA Medical Center, Northport, NY 11768, USA
- Corresponding author. Tel.: +1 631 261 4400x7696; fax: +1 631 266 6016.
Morris S. Gold
- Biostatistician, Novartis Consumer Health, Parsippany, NJ, USA
Keith W. Harris
- Division of Pulmonary/Critical Care Medicine, Stony Brook University School of Medicine, Stony Brook, DVA Medical Center, Northport, NY 11768, USA
Vidal J. Espeleta
- Division of Pulmonary/Critical Care Medicine, Stony Brook University School of Medicine, Stony Brook, DVA Medical Center, Northport, NY 11768, USA
Mohammad M. Amin
- Division of Pulmonary/Critical Care Medicine, Stony Brook University School of Medicine, Stony Brook, DVA Medical Center, Northport, NY 11768, USA
Joan E. Broderick
- Department of Psychiatry and Behavioral Sciences, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA

Received 24 April 2007; received in revised form 24 July 2007; accepted 31 August 2007.

Abstract

Objective

In order to test the hypothesis that upper airway resistance syndrome (UARS) is merely an extension of the pathophysiology of obstructive sleep apnea/hypopnea (OSA/H) to less severe pharyngeal collapse during sleep, we compared the severity of hypersomnolence and the prevalence of insomnia in UARS patients to the patterns observed for OSA/H patients. Our goal was to determine whether the severity of hypersomnolence and the prevalence of insomnia observed in UARS patients could have been predicted from the patterns observed among OSA/H patients.

Methods

We performed a retrospective study of a large consecutive patient series evaluated at an academic sleep disorders center, including 220 OSA/H patients and 137 UARS patients. Patients had no other sleep-related diagnosis and underwent an initial evaluation that included a measure of hypersomnolence [a multiple sleep latency test (MSLT); 95%] or insomnia questionnaire (87%). Patients were characterized by anthropometric data, polysomnographic descriptive measures of sleep, MSLT data and insomnia questionnaire data.

Results

Severity of hypersomnolence decreased over the continuum from severe to mild OSA/H. A model fit to the OSA/H patients to predict severity of hypersomnolence significantly underestimated hypersomnolence in UARS patients, which was comparable in severity to that of patients with mild OSA/H. The frequency of sleep-onset insomnia increased over the continuum from severe to mild OSA/H and increased further in UARS.

Conclusions

UARS is, in some respects, an extension of OSA/H to less severe pharyngeal collapse, but this does not adequately account for the symptom profile of patients with UARS. A physical model is proposed to account for the excess somnolence in UARS relative to expectations and the increasing frequency of sleep-onset insomnia along the continuum from severe OSA/H to UARS.

Keywords: Obstructive sleep apnea/hypopnea, Upper airway resistance syndrome, Insomnia, Hypersomnolence, Multiple sleep latency test, Physiologic hyperarousal