A system for portable sleep apnea diagnosis using an embedded data capturing module

  • Hisham Alshaer
  • Alexander Levchenko
  • T. Douglas Bradley
  • Steven Pong
  • Wen-Hou Tseng
  • Geoff R. Fernie
Original Research


Sleep apnea (SA) is a very common disease with serious health consequences, yet is very under-diagnosed, partially because of the high cost and limited accessibility of in-laboratory polysomnography (PSG). The purpose of this work is to introduce a newly developed portable system for the diagnosis of SA at home that is both reliable and easy to use. The system includes personal devices for recording breath sounds and airflow during sleep and diagnostic algorithms to process the recorded data. The data capturing device consists of a wearable face frame with an embedded electronic module featuring a unidirectional microphone, a differential microphone preamplifier, a microcontroller with an onboard differential analogue to digital converter, and a microSD memory card. The device provides continuous data capturing for 8 h. Upon completion of the recording session, the memory card is returned to a location for acoustic analysis. We recruited 49 subjects who used the device independently at home, after which each subject answered a usability questionnaire. Random data samples were selected to measure the signal-to-noise ratio (SNR) as a gauge of hardware functionality. A subset of 11 subjects used the device on 2 different nights and their results were compared to examine diagnostic reproducibility. Independent of those, system’s performance was evaluated against PSG in the lab environment in 32 subject. The overall success rate of applying the device in un-attended settings was 94 % and the overall rating for ease-of-use was ‘excellent’. Signal examination showed excellent capturing of breath sounds with an average SNR of 31.7 dB. Nine of the 11 (82 %) subjects had equivalent results on both nights, which is consistent with reported inter-night variability. The system showed 96 % correlation with simultaneously performed in-lab PSG. Conclusion: Our results suggest excellent usability and performance of this system and provide a strong rationale to further improve it and test its robustness in a larger study.


Home diagnosis Usability Portable system Embedded module 



The authors are thankful to the contributions of Inas Kadri in developing the illustrations and to Azadeh Yadollahi for her editorial input. This work might result in a commercializable device and patent applications have been filed. This project has been supported by the Ministry of Research and Innovation of Ontario, MaRS Innovation, Ontario Centre of Excellence, Johnson and Johnson Inc., and FedDev via the Ontario Brain Institute. Toronto Rehabilitation Institute receives funding from the Ontario Ministry of Health and Long-Term Care. Dr Alshaer is a recipient NSERC scholarship.


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Hisham Alshaer
    • 1
    • 2
  • Alexander Levchenko
    • 3
  • T. Douglas Bradley
    • 4
  • Steven Pong
    • 3
  • Wen-Hou Tseng
    • 1
  • Geoff R. Fernie
    • 5
  1. 1.Sleep and Upper Airway Team & Technology TeamToronto Rehabilitation Institute, University Health NetworkTorontoCanada
  2. 2.IBBMEUniversity of TorontoTorontoCanada
  3. 3.Technology Team, Toronto Rehabilitation InstituteUniversity Health NetworkTorontoCanada
  4. 4.Sleep and Upper Airway Team, Toronto Rehabilitation InstituteUniversity Health NetworkTorontoCanada
  5. 5.Toronto Rehabilitation InstituteUniversity Health NetworkTorontoCanada

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