title: Breathing and Snoring Sound Characteristics during Sleep in Adults.
abstract: OBJECTIVE
  Sound level meter is the gold standard approach for snoring evaluation. Using this approach, it was established that snoring intensity (in dB) is higher for men and is associated with increased apnea-hypopnea index (AHI). In this study, we performed a systematic analysis of breathing and snoring sound characteristics using an algorithm designed to detect and analyze breathing and snoring sounds. The effect of sex, sleep stages, and AHI on snoring characteristics was explored.
  
  
  METHODS
  We consecutively recruited 121 subjects referred for diagnosis of obstructive sleep apnea. A whole night audio signal was recorded using noncontact ambient microphone during polysomnography. A large number (> 290,000) of breathing and snoring (> 50 dB) events were analyzed. Breathing sound events were detected using a signal-processing algorithm that discriminates between breathing and nonbreathing (noise events) sounds.
  
  
  RESULTS
  Snoring index (events/h, SI) was 23% higher for men (p = 0.04), and in both sexes SI gradually declined by 50% across sleep time (p < 0.01) independent of AHI. SI was higher in slow wave sleep (p < 0.03) compared to S2 and rapid eye movement sleep; men have higher SI in all sleep stages than women (p < 0.05). Snoring intensity was similar in both genders in all sleep stages and independent of AHI. For both sexes, no correlation was found between AHI and snoring intensity (r = 0.1, p = 0.291).
  
  
  CONCLUSIONS
  This audio analysis approach enables systematic detection and analysis of breathing and snoring sounds from a full night recording. Snoring intensity is similar in both sexes and was not affected by AHI.
authors.affiliation: Sleep-Wake Disorders Unit, Soroka University Medical Center and Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.
authors.forename: Asaf
authors.initials: A
authors.lastname: Levartovsky
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Israel.
authors.forename: Eliran
authors.initials: E
authors.lastname: Dafna
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, Israel.
authors.forename: Yaniv
authors.initials: Y
authors.lastname: Zigel
authors.affiliation: Sleep-Wake Disorders Unit, Soroka University Medical Center and Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.
authors.forename: Ariel
authors.initials: A
authors.lastname: Tarasiuk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012119:Respiration; D012737:Sex Factors; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000503:physiopathology; D012894:Sleep Stages / Q000502:physiology; D012913:Snoring / Q000503:physiopathology*; D055815:Young Adult
keywords: breathing; obstructive sleep apnea; sex; snoring; sound analysis