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Nat Sci Sleep. 2017 Jun 6;9:171-180. doi: 10.2147/NSS.S133789. eCollection 2017.

A randomized controlled trial to validate the Alice PDX ambulatory device.

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HELIOS-Klinik Ambrock, Universität Witten-Herdecke, Hagen, Germany.
Service de Physiologie - Explorations Fonctionnelles DHU FIRE, Groupe Hospitalier Bichat-Claude Bernard, Assistance Publique-Hopitaux de Paris.
Université Denis Diderot Paris 7, Paris, France.



Obstructive sleep apnea (OSA) is a highly prevalent condition; however, the majority of patients remain undiagnosed. There is a potential to expand the diagnostic capacity of sleep laboratories. The study objective was to validate a portable respiratory monitoring device (Alice PDX) against polysomnography (PSG) in the laboratory and to assess its reliability at home.


A total of 85 patients with suspected OSA (80% male, mean age 49.1±13.5 years, body mass index 29.7±6.9 kg/m2, Epworth Sleepiness Scale 10.0±5.1) were randomized to 3 diagnostic nights: 1 night simultaneous in-laboratory PSG and PDX recording; 1 night self-applied PDX at home, and 1 night in-laboratory PSG. Study data were manually scored according to American Academy of Sleep Medicine criteria.


The Alice PDX was in diagnostic agreement with simultaneously recorded reference PSG in 96.4% of studies. In 2.4% of studies the in-laboratory PDX underestimated and in 1.2% of studies it overestimated the apnea hypopnea index (AHI). The difference between the AHI from the reference PSG and the home study was similar to the difference between the PSGs (2.79 vs 0.79, p=0.08).


In a population with a high suspicion of OSA, the Alice PDX showed a high level of diagnostic agreement with a simultaneous PSG and performed valid home diagnostic studies for OSA. If manually scored, the portable device can be used by sleep specialists for diagnosing moderate-to-severe obstructive sleep apnea in cases with a high pretest probability for the disease over a wide range of disease severity. The technology can be deployed reliably outside of the sleep laboratory setting.


ambulant monitoring; diagnostic; polysomnography; portable device; sleep apnea

Conflict of interest statement

Disclosure The company had no influence on the data acquisition, study conduct, and interpretation of the data. The authors report no conflicts of interest in this work.

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