title: Analysis of respiratory events in obstructive sleep apnea syndrome: Inter-relations and association to simple nocturnal features.
abstract: OBJECTIVE
  This study carefully evaluates the association of different respiration-related events to each other and to simple nocturnal features in obstructive sleep apnea-hypopnea syndrome (OSAS). The events include apneas, hypopneas, respiratory event-related arousals and snores.
  
  
  METHODS
  We conducted a statistical study on 158 adults who underwent polysomnography between July 2012 and May 2014. To monitor relevance, along with linear statistical strategies like analysis of variance and bootstrapping a correlation coefficient standard error, the non-linear method of mutual information is also applied to illuminate vague results of linear techniques.
  
  
  RESULTS
  Based on normalized mutual information weights (NMIW), indices of apnea are 1.3 times more relevant to AHI values than those of hypopnea. NMIW for the number of blood oxygen desaturation below 95% is considerable (0.531). The next relevant feature is "respiratory arousals index" with NMIW of 0.501. Snore indices (0.314), and BMI (0.203) take the next place. Based on NMIW values, snoring events are nearly one-third (29.9%) more dependent to hypopneas than RERAs.
  
  
  CONCLUSIONS
  1. The more sever the OSAS is, the more frequently the apneic events happen. 2. The association of snore with hypopnea/RERA revealed which is routinely ignored in regression-based OSAS modeling. 3. The statistical dependencies of oximetry features potentially can lead to home-based screening of OSAS. 4. Poor ESS-AHI relevance in the database under study indicates its disability for the OSA diagnosis compared to oximetry. 5. Based on poor RERA-snore/ESS relevance, detailed history of the symptoms plus polysomnography is suggested for accurate diagnosis of RERAs.
authors.affiliation: Department of Electrical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran.
authors.forename: H
authors.initials: H
authors.lastname: Ghandeharioun
authors.affiliation: Department of Neurology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Rezaeitalab
authors.affiliation: Department of Electrical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran. Electronic address: rlotfi@ieee.org.
authors.forename: R
authors.initials: R
authors.lastname: Lotfi
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012120:Respiration Disorders / Q000209:etiology*; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000503:physiopathology
keywords: Analysis of variance; Bootstrapping technique; Mutual information; Obstructive sleep apnea–hypopnea syndrome; Polysomnography; Respiratory events