Description and validation of the apnea risk evaluation system: a novel method to diagnose sleep apnea-hypopnea in the home.

STUDY OBJECTIVES

To evaluate the accuracy and practicality of the Apnea Risk Evaluation System (ARES; Advanced Brain Monitoring; Carlsbad, CA), a limited-channel system for diagnosing sleep apnea/hypopnea in the home.

DESIGN

Prospective randomized study with blinded analysis.

SETTINGS

Two independent, community-based, sleep-disorders centers and the participants' homes.

PARTICIPANTS

Two hundred ninety-nine subjects were recruited, including 210 consecutive willing patients referred by community physicians to the centers because of suspected sleep apnea; 36 "general medical" patients recruited from community physicians' offices; and 53 "presumably healthy" subjects recruited from community centers.

MEASUREMENTS AND RESULTS

Manual scoring of attended in-laboratory full-night or split-night polysomnography by trained technologists supervised by physicians board certified in sleep medicine, and automated scoring of the limited-channel system used attended in the laboratory and unattended at home. The definition of the polysomnography apnea-hypopnea index (AHI) and the ARES respiratory disturbance index was the total number of events divided by the study duration in hours. Two hundred eighty-four valid comparisons of in-laboratory simultaneous polysomnography and ARES and 187 valid comparisons of in-laboratory polysomnography with a separate 2 nights of unattended self-applied ARES Unicorder (Advanced Brain Monitoring) were obtained. A diagnostic AHI cutoff of > 10 was used to establish the accuracy and validity of the ARES. The concurrent in-laboratory comparison yielded a sensitivity of 97.4, a specificity of 85.6, a positive predictive value of 93.6, and a negative predictive value of 93.9; in-home comparison sensitivity, specificity, positive predictive value, and negative predictive value were 91.5, 85.7, 91.5, and 85.7, respectively.

CONCLUSIONS

The ARES demonstrated consistently high sensitivity and specificity for both in-laboratory and in-home recordings. In patients at risk for sleep apnea who do not a priori need an attended study, the ARES could provide a low-cost alternative to traditional polysomnography.