title: [Circadian rhythm : Influence on Epworth Sleepiness Scale score].
abstract: BACKGROUND
  The Epworth Sleepiness Scale (ESS) is frequently used to determine daytime sleepiness in patients with sleep-disordered breathing. It is still unclear whether different levels of alertness induced by the circadian rhythm influence ESS score.
  
  
  OBJECTIVE
  The aim of this study is to investigate the influence of circadian rhythm-dependent alertness on ESS performance.
  
  
  METHODS
  In a monocentric prospective noninterventional observation study, 97 patients with suspected sleep-disordered breathing were investigated with respect to daytime sleepiness in temporal relationship to polysomnographic examination and treatment. The Karolinska Sleepiness Scale (KSS) and the Stanford Sleepiness Scale (SSS) served as references for the detection of present sleepiness at three different measurement times (morning, noon, evening), prior to and following a diagnostic polysomnography night as well as after a continuous positive airway pressure (CPAP) titration night (9 measurements in total). The KSS, SSS, and ESS were performed at these times in a randomized order.
  
  
  RESULTS
  The KSS and SSS scores revealed a circadian rhythm-dependent curve with increased sleepiness at noon and in the evening. Following a diagnostic polysomnography night, the scores were increased compared to the measurements prior to the night. After the CPAP titration night, sleepiness in the morning was reduced. KSS and SSS reflect the changes in alertness induced by the circadian rhythm. The ESS score war neither altered by the intra-daily nor by the inter-daily changes in the level of alertness.
  
  
  CONCLUSIONS
  According to the present data, the ESS serves as a reliable instrument to detect the level of daytime sleepiness independently of the circadian rhythm-dependent level of alertness.
authors.affiliation: Klinik für Hals-Nasen-Ohrenheilkunde, Kopf- und Halschirurgie, Carl-Thiem-Klinikum GmbH, Thiemstr. 111, 03048, Cottbus, Deutschland. m.herzog@ctk.de.|Klinik und Poliklinik für Hals-Nasen-Ohren-Heilkunde, Kopf- und Halschirurgie, Martin-Luther-Universität Halle-Wittenberg, Ernst-Grube-Straße 40, 01620, Halle (Saale), Deutschland. m.herzog@ctk.de.
authors.forename: M
authors.initials: M
authors.lastname: Herzog
authors.affiliation: , Habersaathstraße 38e, 10115, Berlin, Deutschland.
authors.forename: A
authors.initials: A
authors.lastname: Bedorf
authors.affiliation: Klinik und Poliklinik für Hals-Nasen-Ohren-Heilkunde, Universitätsklinikum Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Deutschland.
authors.forename: C
authors.initials: C
authors.lastname: Rohrmeier
authors.affiliation: Klinik und Poliklinik für Hals-Nasen-Ohren-Heilkunde, Universitätsklinikum Regensburg, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Deutschland.
authors.forename: T
authors.initials: T
authors.lastname: Kühnel
authors.affiliation: Institut für Medizinische Epidemiologie, Biometrie und Informatik, Martin-Luther-Universität Halle-Wittenberg, Magdeburger Straße 8, 06112, Halle (Saale), Deutschland.
authors.forename: B
authors.initials: B
authors.lastname: Herzog
authors.affiliation: Klinik und Poliklinik für Hals-, Nasen-, Ohrenkrankheiten, Kopf- und Halschirurgie, Universitätsmedizin Greifswald, Sauerbruchstrasse, 17475, Greifswald, Deutschland.
authors.forename: T
authors.initials: T
authors.lastname: Bremert
authors.affiliation: Klinik und Poliklinik für Hals-Nasen-Ohren-Heilkunde, Kopf- und Halschirurgie, Martin-Luther-Universität Halle-Wittenberg, Ernst-Grube-Straße 40, 01620, Halle (Saale), Deutschland.
authors.forename: S
authors.initials: S
authors.lastname: Plontke
authors.affiliation: Klinik und Poliklinik für Hals-Nasen-Ohren-Heilkunde, Kopf- und Halschirurgie, Martin-Luther-Universität Halle-Wittenberg, Ernst-Grube-Straße 40, 01620, Halle (Saale), Deutschland.
authors.forename: S
authors.initials: S
authors.lastname: Plößl
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D002940:Circadian Rhythm; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D017286:Polysomnography / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology
keywords: Neuropsychological tests; Obstructive sleep apnea syndrome; Polysomnography; Sleep; Sleep-disordered breathing