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=3 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 vs. 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 vs. 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 min (5.55, 23.20) for TST, −13.1 min (−21.33, −6.21) for WASO, 2.97% (1.25, 4.84) for SE, −1.34 min (−7.29, 4.81) for SOL, 1.91 min (−8.28, 11.98) for light sleep duration, 5.24 min (−3.35, 14.13) for deep sleep duration, and 6.39 min (−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).