title: How is the Epworth Sleepiness Scale related with subjective sleep quality and polysomnographic features in patients with sleep-disordered breathing?
abstract: OBJECTIVE
  To determine the relationship between the Epworth Sleepiness Scale (ESS) and the Subjective Sleep Quality (SSQ) or polysomnographic (PSG) features in patients with sleep-disordered breathing (SDB).
  
  
  METHODS
  This is a retrospective study that included 646 untreated patients with a PSG diagnosis of primary snoring (PS) or obstructive sleep apnea syndrome. Patients with SDB were grouped into four categories according to ESS scores: no diurnal sleepiness (DS) = 0-6; mild DS = 7-12; moderate DS = 13-18, and severe DS = ≥19. Analyses of variance were performed to compare SSQ or PSG features among the four ESS severity categories.
  
  
  RESULTS
  We found a significant increase in subjective sleep time in the group of patients with severe DS. With regard to PSG data, we also identified increases in total sleep time (TST) and rapid eye movement (REM) in the group of patients with severe DS.
  
  
  CONCLUSIONS
  Unexpectedly, DS severity was related with increases in TST and REM sleep. As has been described in SDB patients, a change in muscular tonus throughout sleep onset (and depth) is a causal factor of SDB features and DS impairment. Therefore, we propose that increases in TST and REM are worsening factors of SDB and consequently, also in DS.
authors.affiliation: Universidad Nacional Autónoma de México, Distrito Federal, México. ulisesjc@yahoo.com
authors.forename: Ulises
authors.initials: U
authors.lastname: Jiménez-Correa
authors.forename: Reyes
authors.initials: R
authors.lastname: Haro
authors.forename: Rosa Obdulia
authors.initials: RO
authors.lastname: González-Robles
authors.forename: Javier
authors.initials: J
authors.lastname: Velázquez-Moctezuma
mesh_terms: D000328:Adult; D001294:Attitude to Health; D015992:Body Mass Index; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000523:psychology; D012895:Sleep, REM; D012913:Snoring / Q000175:diagnosis / Q000523:psychology; D013223:Statistics as Topic; D011795:Surveys and Questionnaires