title: A Comprehensive Evaluation of a Two-Channel Portable Monitor to "Rule in" Obstructive Sleep Apnea.
abstract: OBJECTIVE
  We hypothesized that a dual-channel portable monitor (PM) device could accurately identify patients who have a high pretest probability of obstructive sleep apnea (OSA), and we evaluated factors that may contribute to variability between PM and polysomnography (PSG) results.
  
  
  METHODS
  Consecutive clinic patients (N = 104) with possible OSA completed a home PM study, a PM study simultaneous with laboratory PSG, and a second home PM study. Uniform data analysis methods were applied to both PM and PSG data. Primary outcomes of interest were the positive likelihood ratio (LR+) and sensitivity of the PM device to "rule-in" OSA, defined as an apnea-hypopnea index (AHI) ≥ 5 events/h on PSG. Effects of different test environment and study nights, and order of study and analysis methods (manual compared to automated) on PM diagnostic accuracy were assessed.
  
  
  RESULTS
  The PM has adequate LR+ (4.8), sensitivity (80%), and specificity (83%) for detecting OSA in the unattended home setting when benchmarked against laboratory PSG, with better LR+ (> 5) and specificity (100%) and unchanged sensitivity (80%) in the simultaneous laboratory comparison. There were no significant night-night (all p > 0.10) or study order effects (home or laboratory first, p = 0.08) on AHI measures. Manual PM data review improved case finding accuracy, although this was not statistically significant (all p > 0.07). Misclassification was more frequent where OSA was mild.
  
  
  CONCLUSIONS
  Overall performance of the PM device is consistent with current recommended criteria for an "acceptable" device to confidently "rule-in" OSA (AHI ≥ 5 events/h) in a high pretest probability clinic population. Our data support the utility of simple two-channel diagnostic devices to confirm the diagnosis of OSA in the home environment.
  
  
  CONCLUSIONS
  A commentary on this article appears in this issue on page 411.
authors.affiliation: School of Population Health, The University of Western Australia, Perth, Australia.|Western Australian Sleep Disorders Research Institute, Queen Elizabeth Medical Centre, Perth, Australia.
authors.forename: Kim L
authors.initials: KL
authors.lastname: Ward
authors.affiliation: Western Australian Sleep Disorders Research Institute, Queen Elizabeth Medical Centre, Perth, Australia.|Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, Australia.
authors.forename: Nigel
authors.initials: N
authors.lastname: McArdle
authors.affiliation: Western Australian Sleep Disorders Research Institute, Queen Elizabeth Medical Centre, Perth, Australia.|Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, Australia.|School of Medicine and Pharmacology, The University of Western Australia, Perth, Australia.
authors.forename: Alan
authors.initials: A
authors.lastname: James
authors.affiliation: School of Population Health, The University of Western Australia, Perth, Australia.
authors.forename: Alexandra P
authors.initials: AP
authors.lastname: Bremner
authors.affiliation: School of Anatomy and Human Biology, The University of Western Australia, Perth, Australia.
authors.forename: Laila
authors.initials: L
authors.lastname: Simpson
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Subiaco, Australia.
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Cooper
authors.affiliation: The Joanna Briggs Institute and School of Translational Health Science, University of Adelaide, Adelaide, Australia.
authors.forename: Lyle J
authors.initials: LJ
authors.lastname: Palmer
authors.affiliation: Center for Sleep and Circadian Neurobiology, University of Pennsylvania, PA.
authors.forename: Annette C
authors.initials: AC
authors.lastname: Fedson
authors.affiliation: Western Australian Sleep Disorders Research Institute, Queen Elizabeth Medical Centre, Perth, Australia.
authors.forename: Sutapa
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Western Australian Sleep Disorders Research Institute, Queen Elizabeth Medical Centre, Perth, Australia.|Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Perth, Australia.
authors.forename: David R
authors.initials: DR
authors.lastname: Hillman
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D017286:Polysomnography; D015203:Reproducibility of Results; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology
keywords: obstructive sleep apnea; portable monitor; positive likelihood ratio; rule-in; sensitivity; type 4; validation