title: Can sleep microstructure improve diagnosis of OSAS? Integrative information from CAP parameters.
abstract: OBJECTIVE
  The scoring of American Academy of Sleep Medicine (AASM) arousal is mandatory for the definition of respiratory event-related arousal (RERA). However there are other EEG activation phenomena, such as A phases of cyclic alternating pattern (CAP) which are associated with respiratory events in non rapid eye movements (NREM) sleep. This study aims at quantifying the additional value of CAP for the definition of respiratory events and sleep alterations in OSAS.
  
  
  METHODS
  Analysis of polysomnographic recordings from nineteen OSAS patients was carried out. Scoring was focused on investigation of the cerebral response to flow limitation (FL) events. For this purpose we used both CAP rules and AASM arousal criteria.
  
  
  RESULTS
  While no difference was demonstrated in the arousal index between mild and moderate-severe OSAS patients, CAP time showed a progressive enhancement from normal subjects (152.5±20.76) to mild (180.64±34.76) and moderate-severe (282.27±58.02) OSAS patients. In NREM sleep, only 41.1% of FL events met the criteria for the definition of RERA, while, 75.5% of FL events ended with a CAP A phase and most FL CAP (69.1%) terminated with a CAP phase A3 subtype.
  
  
  CONCLUSIONS
  Our data indicate that the RERA scoring has a limited accuracy in the detection of FL events. In NREM sleep, CAP rules provided more information than AASM arousal for the definition of respiratory events and sleep alterations in OSAS.
authors.affiliation: Sleep Disorders Center, Dept of Neurosciences, University of Parma, Italy. Email: giulia.milioli@gmail.com.
authors.forename: Giulia
authors.initials: G
authors.lastname: Milioli
authors.forename: Marcello
authors.initials: M
authors.lastname: Bosi
authors.forename: Andrea
authors.initials: A
authors.lastname: Grassi
authors.forename: Silvia
authors.initials: S
authors.lastname: Riccardi
authors.forename: Mario Giovanni
authors.initials: MG
authors.lastname: Terzano
authors.forename: Pietro
authors.initials: P
authors.lastname: Cortelli
authors.forename: Venerino
authors.initials: V
authors.lastname: Poletti
authors.forename: Liborio
authors.initials: L
authors.lastname: Parrino
mesh_terms: D000328:Adult; D058256:Brain Waves; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods*; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D012895:Sleep, REM