Validation of MotionWatch8 Actigraphy Against Polysomnography in Menopausal Women Under Warm Conditions

Abstract

What are the main findings? MotionWatch8 overestimated TST and SE while it underestimated SOL and WASO. MotionWatch8 showed high sensitivity for sleep detection (94.8%) but low specificity for wake detection (33.1%), with an overall accuracy of 87.3%. What is the implication of the main finding? MotionWatch8 may be less reliable for individuals with more extreme sleep characteristics (SOL > 30 min and WASO > 80 min (criteria that fall under insomnia in DSM-5), and SE < 77%). Caution is needed when using this device in clinical populations with sleep disturbances Highlights: This study evaluated the agreement between MotionWatch8 actigraphy and polysomnography (PSG) in measuring sleep parameters among menopausal women under controlled 30 °C laboratory conditions. Sixteen peri- and post-menopausal women (age: 51.4 ± 4.2 years, BMI: 26.0 ± 3.1 kg/m2) contributed 59 nights of simultaneous recordings, with parameters analyzed using Bland–Altman plots, linear mixed model analysis, and epoch-by-epoch comparisons. Results showed MotionWatch8 significantly overestimated total sleep time by 18.6 min and sleep efficiency by 3.5%, while underestimating sleep onset latency by 11.2 min and wake after sleep onset by 9.1 min compared to PSG. Significant proportional errors were observed, particularly for participants with prolonged sleep onset latency, high wake after sleep onset, and lower sleep efficiency. Epoch-by-epoch analysis revealed high sensitivity for sleep detection (94.8%) but low specificity for wake detection (33.1%), with 87.3% overall accuracy. These findings demonstrate that MotionWatch8 may be less reliable for individuals with more extreme sleep characteristics, such as insomnia, as measurement accuracy declines with increasing severity of sleep disturbances, highlighting the need for caution when using this device for detailed sleep assessments in clinical populations with sleep disturbances.