title: Respiratory cycle-related EEG changes: response to CPAP.
abstract: OBJECTIVE
  Respiratory cycle-related EEG changes (RCREC) quantify statistically significant synchrony between respiratory cycles and EEG spectral power, vary to some extent with work of breathing, and may help to predict sleepiness in patients with obstructive sleep apnea. This study was designed to assess the acute response of RCREC to relief of upper airway obstruction by positive airway pressure (PAP).
  
  
  METHODS
  Comparison of RCREC between baseline diagnostic polysomnograms and PAP titration studies.
  
  
  METHODS
  Accredited academic sleep disorders center.
  
  
  METHODS
  Fifty adults referred for suspected sleep disordered breathing.
  
  
  METHODS
  For each recording, the RCREC in specific physiologic EEG frequency ranges were computed as previously described for the last 3 h of sleep not occupied by apneic events.
  
  
  RESULTS
  The sample included 27 women; mean age was 47 ± 11 (SD) years; and median respiratory disturbance index at baseline was 24 (inter-quartile range 15-43). Decrements in RCREC, from baseline to PAP titration, reached 43%, 24%, 14%, 22%, and 31% for delta (P = 0.0004), theta (P = 0.01), alpha (P = 0.10), sigma (P = 0.08), and beta (P = 0.01) EEG frequency ranges, respectively. Within each specific sleep stage, these reductions from baseline to PAP studies in synchrony between EEG power and respiratory cycles still reached significance (P < 0.05) for one or more EEG frequency ranges and for all frequency ranges during REM sleep.
  
  
  CONCLUSIONS
  RCREC tends to diminish acutely with alleviation of upper airway obstruction by PAP. These data in combination with previous observations support the hypothesis that RCREC reflect numerous, subtle, brief, but consequential inspiratory microarousals.
authors.affiliation: Sleep Disorders Center and Department of Neurology, University of Michigan, Ann Arbor, MI, USA. chervin@umich.edu
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Chervin
authors.forename: Anita Valanju
authors.initials: AV
authors.lastname: Shelgikar
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Burns
mesh_terms: D000704:Analysis of Variance; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010507:Periodicity; D017286:Polysomnography / Q000379:methods; D012119:Respiration; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012815:Signal Processing, Computer-Assisted; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D012894:Sleep Stages; D014939:Work of Breathing