In-home validation of wrist- and waist-worn devices against portable electroencephalography for sleep assessment in community-dwelling older adults.

Sleep health is essential for older adults. However, the validity of wrist- and waist-worn devices for assessing sleep under free-living conditions in community-dwelling older adults remains unclear. This study evaluated the accuracy of a wrist-worn smartwatch (Silmee W22) and a waist-worn activity monitor (MTN-221) in measuring key sleep parameters, using portable electroencephalography (EEG; Insomnograf K2) as the reference. Healthy community-dwelling older adults wore all devices simultaneously for at least three nights. Total sleep time, sleep onset latency, wake after sleep onset, and sleep efficiency were analyzed using Bland-Altman plots, multilevel models, and intraclass correlation coefficients (ICCs). Fifty-five participants completed the study, yielding valid EEG-paired data for 49 participants with Silmee W22 (238 nights) and 53 with MTN-221 (265 nights). Silmee W22 overestimated total sleep time by 35 min and sleep efficiency by 8.1%, whereas MTN-221 underestimated it by 3 min and sleep efficiency by 1.0%. Both devices underestimated sleep onset latency, whereas the direction of bias for wake after sleep onset differed between devices. ICCs for total sleep time were 0.60-0.75 and 0.66-0.79 for Silmee W22 and MTN-221, respectively, while agreement for sleep onset latency and wake after sleep onset remained lower. While Silmee W22 did not provide sufficiently accurate estimates of total sleep time, MTN-221 provided comparatively accurate total sleep time estimates, supporting large-scale monitoring of sleep duration in community-dwelling older adults. However, wake- and sleep quality related metrics should be interpreted cautiously due to probable misclassification of quiet wakefulness. Further algorithm refinement is warranted.