Screening for obstructive sleep apnea using a contact-free system compared with polysomnography

Study objectives: To evaluate the utility of a contact-free device in screening for obstructive sleep apnea.

Methods: Three hundred fifty-nine participants (mean age 46 ± 13 years, body mass index 26.1 ± 4.2 kg/m², 67.7% male) underwent overnight monitoring using a contact-free device, the OrbSense, and polysomnography (PSG) in the sleep laboratory simultaneously. The OrbSense recordings were analyzed automatically, and PSG was scored based on recommended guidelines.

Results: The respiratory event index from the OrbSense was lower than the apnea-hypopnea index (AHI) from PSG (25.5 ± 20.7 vs 27.0 ± 25.2 events/h; P = .007) and was significantly correlated with AHI (Pearson coefficient, 0.92; P < .0001). Bland-Altman analysis showed a mean difference of 1.5 events/h, and the limit of agreement was -18.6 to 21.5 events/h. Use of the OrbSense resulted in larger underestimates of AHI and lower negative predictive values at higher AHI values (especially when AHI ≥ 30 events/h). When we used a PSG diagnostic criterion of AHI > 5 events/h, the optimal diagnostic cutoff value from the OrbSense was 8 events/h, with a sensitivity of 90.4%, a specificity of 77.6%, a 94.6% positive predictive value, and a 65% negative predictive value. For patients with moderate to severe obstructive sleep apnea whose AHI was > 15 events/h, the OrbSense cutoff was 16.6 events/h, with a sensitivity of 87.1% and a specificity of 89.7%. Among the 359 participants, 250 patients (69.6%) had the same obstructive sleep apnea severity division classified by both PSG and the OrbSense.

Conclusions: The contact-free device OrbSense can detect respiratory events during sleep and has close agreement with in-laboratory PSG in screening for obstructive sleep apnea. Further studies are warranted to test its utility in community-based settings and at home.