AUTHOR=Saeb Sohrab , Nelson Benjamin W. , Barman Poulami , Verma Nishant , Allen Hannah , de Zambotti Massimiliano , Baker Fiona C. , Arra Nicole , Sridhar Niranjan , Sullivan Shannon S. , Plowman Scooter , Rainaldi Erin , Kapur Ritu , Shin Sooyoon 

TITLE=Performance of the Verily Study Watch for measuring sleep compared to polysomnography

JOURNAL=Frontiers in Sleep

VOLUME=Volume 3 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/sleep/articles/10.3389/frsle.2024.1481878

DOI=10.3389/frsle.2024.1481878

ISSN=2813-2890

ABSTRACT=Introduction: This study evaluated the performance of a wrist-worn wearable, Verily Study Watch (VSW), in detecting key sleep measures against polysomnography (PSG). Methods: We collected data from 41 adults without obstructive sleep apnea or insomnia during a single overnight laboratory visit. We evaluated epoch-by-epoch performance for sleep versus wake classification, sleep stage classification and duration, total sleep time (TST), wake after sleep onset (WASO), sleep onset latency (SOL), sleep efficiency (SE), and number of awakenings (NAWK). Performance metrics included sensitivity, specificity, Cohen’s kappa, and Bland-Altman analyses. Results: Sensitivity and specificity (95% CIs) of sleep versus wake classification were 0.97 (0.96, 0.98) and 0.70 (0.66, 0.74), respectively. Cohen’s kappa (95% CI) for 4-class stage detection was 0.64 (0.18, 0.82). Most VSW sleep measures had proportional bias. The mean bias values (95% CI) were 14.0 minutes (5.55, 23.20) for TST, -13.1 minutes (-21.33, -6.21) for WASO, 2.97% (1.25, 4.84) for SE, -1.34 minutes (-7.29, 4.81) for SOL, 1.91 minutes (-8.28, 11.98) for light sleep duration, 5.24 minutes (-3.35, 14.13) for deep sleep duration, and 6.39 minutes (-0.68, 13.18) for REM sleep duration. Mean and median NAWK count differences (95% CI) were 0.05 (-0.42, 0.53) and 0.0 (0.0, 0.0), respectively. Discussion: Results support applying the VSW to track overnight sleep measures in free-living settings. Registered at clinicaltrials.gov (NCT05276362).