HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Grenèche, J. Articles by Tassi, P. PubMed PubMed Citation Articles by Grenèche, J. Articles by Tassi, P.

Severity of obstructive sleep apnoea/hypopnoea syndrome and subsequent waking EEG spectral power

¹ Laboratory of Imaging and Cognitive Neuroscience (LINC CNRS), ² University Louis Pasteur, ³ Federal Institute of Neurosciences (IFR 37), ⁴ Sleep Disorders Unit, Civil Hospital, Strasbourg, and ⁵ Forenap FRP, Rouffach, France.

CORRESPONDENCE: J. Grenèche, LINC (Laboratoire d’Imagerie et de Neurosciences Cognitives), CNRS-UMR 7191, 21 rue Becquerel, 67087 Strasbourg, France. Fax: 33 388106245. E-mail: Jerome.Greneche{at}linc.u-strasbg.fr

Keywords: Daytime sleepiness, nocturnal hypoxaemia, obstructive sleep apnoea/hypopnoea syndrome, spectral analysis, sustained wakefulness, waking electroencephalogram

Received: September 5, 2007
Accepted April 17, 2008

It is well known that most patients with obstructive sleep apnoea/hypopnoea syndrome (OSAHS) suffer sleepiness, although the underlying mechanisms of this relationship remain unclear. The present study examined the relationship between nocturnal variables and the subsequent waking electroencephalogram (EEG), in order to determine if sleepiness was related to OSAHS severity and due to sleep fragmentation or to nocturnal hypoxaemia.

In total, 12 moderate-to-severe OSAHS patients underwent a total sleep night followed by a 24-h period of sustained wakefulness where the waking EEG was measured every hour.

The results showed that alpha (7.9–12.6 Hz) and beta (12.7–29.2 Hz) activities were strongly related to OSAHS severity, mainly reflected by the apnoea index. Moreover, spectral power in most of the waking EEG components was significantly correlated with nocturnal hypoxaemia indices, namely alpha and beta activity when hypoxaemia becomes severe. However, no correlation was found between the waking EEG and sleep fragmentation parameters.

In conclusion, the present results suggest that the difficulty in maintaining an optimal level of alertness, reflected by a higher activity in awake alpha and beta bands (7.9–29.2 Hz) in obstructive sleep apnoea/hypopnoea syndrome, was better explained by: 1) the apnoea as opposed to the hypopnoea index; and 2) nocturnal hypoxaemia as opposed to sleep fragmentation.