In a head-to-head comparison between the WatchPAT home sleep apnea screening device by Itamar Medical, Framingham, Mass, and in-laboratory attended polysomnography (PSG), researchers found that the WatchPAT had a high degree of correlation on the key measures of apnea-hypopnea index (AHI), lowest oxygen saturation (LSAT), and sleep time, leading them to conclude that the device might be reliable enough to be used for the diagnosis of sleep apnea.

Physicians at the Department of Otolaryngology–Head and Neck Surgery at the Medical College of Georgia in Augusta had 37 patients (12 men and 25 women) with suspected sleep apnea wear the WatchPAT device on their wrists during their in-laboratory attended polysomnograms. This ensured that the sleep measured by the two diagnostic methods was exactly the same. Furthermore, the test was constructed so that neither the principal investigator nor the sleep physician could compare the results directly in order to avoid any bias toward or against either testing method.

Five of the 37 subjects were eliminated because they did not sleep long enough in the laboratory for proper diagnosis. The remaining 32 sets of results were sent to Kenny P. Pang, FRCSEd, FRCSI(OTO)a, of the Pacific Sleep Centre in Singapore, who did the statistical analysis of the results. He found that the mean AHI for the PSG was 34.87, while the mean AHI for the WatchPAT was 35.10. The mean LSAT from the PSG was 82.03%, while the mean LSAT from the WatchPAT was 81.46%. Finally, the mean total sleep time for the PSG was 5.65 hours, while that of the WatchPAT was 5.33 hours.

Because there was such a high degree of correlation between the results in this study, and in previous comparison studies of the WatchPAT and PSG, the researchers came out in favor of its use. The study authors wrote: “Given the high prevalence of OSA and limited capacity for sleep laboratory testing, there is a clear need for home diagnostic devices. The WatchPAT is small, lightweight, inexpensive, reliable, accurate, easy to use, and safe. It also demonstrates high correlation with the gold standard polysomnogram (PSG).”

The study appears in the October edition of the journal Otolaryngology - Head and Neck Surgery. Itamar Medical has posted information about the WatchPAT online.