In-home validation of wrist actigraphy against portable electroencephalography for sleep assessment in older adults

While accurate sleep measurement is vital for older adults, the validity of actigraphy in free-living environments remains controversial, particularly given the flexible sleep-wake schedules common in this demographic. To address this uncertainty, we assessed the accuracy of wrist actigraphy against in-home portable electroencephalography (EEG) among community-dwelling older adults.

Relatively healthy community-dwelling older adults underwent concurrent sleep monitoring using a portable EEG device and a wrist-worn actigraphy for five consecutive nights whenever possible, with monitoring extended to up to seven nights when feasible. Key sleep parameters, including total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency, were derived from both devices. Measurement agreement was assessed using Bland-Altman plots and multilevel modeling, while reliability and accuracy were quantified via intraclass correlation coefficients (ICCs) and mean absolute percentage error (MAPE).

Forty-nine adults contributed 217 nights of recordings. On average, actigraphy slightly overestimated TST and sleep efficiency and underestimated SOL and WASO compared with EEG. Single-measure ICCs were 0.73 for TST and 0.38 for WASO (0.84 and 0.55 for averages across nights), and the MAPE was 11% for TST but exceeded 50% for SOL and WASO, indicating poor accuracy for these indices.

Wrist actigraphy provided acceptable estimates of average TST for epidemiological monitoring but showed substantial errors for SOL and WASO. These findings, based on relatively healthy community-dwelling older adults, should not be generalized to older adults with clinically significant sleep disorders or broader clinical populations.