title: Daytime sleepiness and polysomnography in obstructive sleep apnea patients.
abstract: BACKGROUND
  Excessive daytime sleepiness (EDS) is the major complaint in subjects with obstructive sleep apnea syndrome (OSAS). However, EDS is not universally present in all patients with OSAS. The mechanisms explaining why some patients with OSAS complain of EDS whereas others do not are unknown.
  
  
  OBJECTIVE
  To investigate polysomnographic determinants of excessive daytime sleepiness (EDS) in a large multicenter cohort of patients with obstructive sleep apnea (OSAS).
  
  
  METHODS
  All consecutive patients with an apnea-hypopnea index greater than 5h(-1) who were evaluated between 2003 and 2005. EDS was assessed using the Epworth Sleepiness Scale (ESS), and patients were considered to have EDS if the ESS was >10.
  
  
  RESULTS
  A total of 1649 patients with EDS ((mean [+/-SD] Epworth 15+/-3) and 1233 without EDS (Epworth 7+/-3) were studied. Patients with EDS were slightly younger than patients without EDS (51+/-12 vs 54+/-13 years, p<0.0001), had longer total sleep time (p<0.007), shorter sleep latency (p<0001), greater sleep efficiency (p<0.0001) and less NREM sleep in stages 1 and 2 (p<0.007) than those without EDS. Furthermore, patients with EDS had slightly higher AHI (p<0.005) and arousal index (p<0.001) and lower nadir oxygen saturation (p<0.01).
  
  
  CONCLUSIONS
  Patients with OSAS and EDS are characterized by longer sleep duration and increased slow wave sleep compared to those without EDS. Although patients with EDS showed a mild worsening of respiratory disturbance and sleep fragmentation, these results suggest that sleep apnea and sleep disruption are not the primary determinants of EDS in all of these patients.
authors.affiliation: Servei de Pneumología, Hospital Univ Arnau de Vilanova, IRBLLEIDA, Lleida, Catalunya, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Roure
authors.forename: Silvia
authors.initials: S
authors.lastname: Gomez
authors.forename: Olga
authors.initials: O
authors.lastname: Mediano
authors.forename: Joaquin
authors.initials: J
authors.lastname: Duran
authors.forename: Monica de la
authors.initials: Mde L
authors.lastname: Peña
authors.forename: Francisco
authors.initials: F
authors.lastname: Capote
authors.forename: Joaquin
authors.initials: J
authors.lastname: Teran
authors.forename: Juan Fernando
authors.initials: JF
authors.lastname: Masa
authors.forename: Maria Luz
authors.initials: ML
authors.lastname: Alonso
authors.forename: Jaime
authors.initials: J
authors.lastname: Corral
authors.forename: Angeles
authors.initials: A
authors.lastname: Sánchez-Armengod
authors.forename: Cristina
authors.initials: C
authors.lastname: Martinez
authors.forename: Antonia
authors.initials: A
authors.lastname: Barceló
authors.forename: David
authors.initials: D
authors.lastname: Gozal
authors.forename: Jose Maria
authors.initials: JM
authors.lastname: Marín
authors.forename: Ferran
authors.initials: F
authors.lastname: Barbé
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001143:Arousal; D002940:Circadian Rhythm; D015331:Cohort Studies; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000175:diagnosis; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D012894:Sleep Stages
chemical_list: D010100:Oxygen