Toevaluate the performance of a multi-sensor sleep-tracker (ŌURA ring) against polysomnography (PSG) in measuring sleep and sleep stages.
Sleep data were recorded using the ŌURA ring and standard PSG on a single laboratory overnight. Metrics were compared using Bland-Altman plots and epoch-by-epoch (EBE) analysis.
Summary variables for sleep onset latency (SOL), total sleep time (TST) and wake after sleep onset (WASO) were not different between ŌURA ring and PSG. PSG-ŌURA discrepancies for WASO were greater in participants with more PSG-defined WASO (p<.001). Compared with PSG, ŌURA ring underestimated PSG N3 (~20 min) and overestimated PSG REM (~17 min) (p<.05). PSG-ŌURA differences for TST and WASO lay within the ≤30 min a-priori-set clinically satisfactory ranges for 87.8% and 85.4% of the sample, respectively. From EBE analysis, ŌURA ring had a 96% sensitivity to detect sleep,and agreement of 65%, 51%, and 61%, in detecting “light sleep” (N1+N2), “deep sleep” (N3),and REM sleep, respectively. Specificity in detecting wake was 48%. Similarly to PSG-N3 (p<.001), “deep sleep” detected with the ŌURA ring was negatively correlated with advancing age (p=.001). ŌURA ring correctly categorized 90.9%, 81.3%, and 92.9% into PSG-defined TST ranges of <6h, 6–7h, >7h, respectively.