Can arterial tonometry-based detection of obstructive sleep apnea be a promising alternative for home sleep apnea tests?

Polysomnography is the gold-standard diagnostic test for obstructive sleep apnea (OSA) [1]. However, during polysomnography, sleep might differ from usual sleep at home because of the wearing of numerous sensors, sleeping in an unfamiliar environment in the hospital, and only one night of testing. In general, polysomnography must be performed in a sleep laboratory with specialized medical personnel, which limits the number of facilities where the test can be performed. The test cost is also high, leading to a financial burden on patients and/or health insurance systems. Against this background, there is a need for sleep tests that can be performed easily and are less expensive. Many products for home sleep apnea test (HSAT) have been developed. Some HSAT devices are based on unique technologies, such as arterial tonometry, and have been used clinically [2, 3].

In this issue of Sleep and Biological Rhythms, McMahon et al. compared data in the AHI and other parameters such as total sleep time and oxygen desaturation index by polysomnography and Somfit, which is a new HSAT device based on pulse arterial tonometry and is attached to the patient’s forehead [4]. Somfit provides frontal neurological signals to detect sleep stages, pulse arterial tonometry, pulse oximetry, pulse rate, respiratory rate, temperature, snoring, accelerometer-derived head position, and motion. Authors assessed 92 participants with suspected OSA using overnight polysomnography recordings and simultaneously recorded Somfit signals. They found that the total sleep time, oxygen desaturation index, and AHI by Somfit were highly correlated with those obtained by polysomnography, which provided acceptable sensitivity, specificity, and accuracy. These findings suggest that Somfit’s performance was comparable to that of polysomnography in detecting OSA severity.

However, the results of this study should be interpreted with caution due to the following issues. First, although the authors themselves addressed this as a major limitation, inter-scorer agreement regarding manual scoring of polysomnography was relatively low, in association with the fact that manual scoring was performed by three scorers. In this study, all scoring was performed by an experienced scorer. Second, details of participants’ characteristics, such as the presence or severity of atherosclerotic diseases, which may affect respiratory variables determined by arterial tonometry-based technology [5], and whether any vasodilators other than alpha-blockers were used were elucidated. Third, beyond the awaken/sleep state, the accuracy of the sleep stage determined based on Somfit can affect the correlation between the AHI by polysomnography and Somfit. However, data on sleep stages were not obtained in this study. Finally, comparative data between Somfit and other arterial tonometry-based HSAT are lacking. Nevertheless, the results of this study provide novel and important insights into pulse arterial tonometry-based detection of OSA. Further studies are needed to clarify whether arterial tonometry-based detection of obstructive sleep apnea can be a promising alternative for home sleep apnea tests.

Funding

This was supported by JSPS KAKENHI (Grant Numbers: 17K09527, 18K15904, JP21K08116, JP21K16034), Grant-in-Aid for Scientific Research (Grant Number: 20FC1027, 23FC1031) from the Ministry of Health, Labor, and Welfare of Japan, and a research grant from the Japanese Center for Research on Women in Sport, Juntendo University. These funding sources do not have any other roles.

Declarations

Conflict of interest

Nanako Shiroshita and Takatoshi Kasai are affiliated with departments endowed by Philips, ResMed, and Fukuda Denshi, and by Paramount Bed.