Feasibility and Methodological Consideration of Using Wearable Devices to Examine the Relationship Between Sleep and...

This exploratory case study primarily examined the feasibility of using consumer-grade wearable devices for longitudinal sleep tracking and observed descriptive visual trends between sleep patterns and balance performance. Two college students participated over 4 months. Participant 1 used an Apple Watch Series 5 and an OURA ring; participant 2 used a Fitbit Charge 5 and an OURA ring. Data were collected continuously alongside daily sleep diaries and monthly sensory organization test (SOT) balance assessments. As a primary feasibility outcome, missing data rates were initially high (up to 75.2%) but improved significantly after implementing structured weekly check-ins, dropping to 14.1% and 20.3% for the wrist devices, 9.4% and 25% for the OURA rings, and 0% and 6.25% for the sleep diaries in the optimized phase. Wearables showed varying concordance with sleep diaries for time in bed (TIB), with the Apple Watch showing the least bias (-0.6 min) and the Fitbit and OURA overestimating TIB. While devices showed excellent within-participant agreement for total sleep time (intraclass correlation coefficient=0.97-0.99), agreement was poor for specific sleep stages. Regarding secondary exploratory observations, descriptive visual trends showed that fluctuations in sleep timing and duration coincided with changes in SOT visual subscale scores. In conclusion, consumer wearables are feasible for long-term sleep monitoring when supported by active compliance protocols. While sleep consistency was visually patterned alongside postural stability, these balance findings are strictly exploratory, hypothesis-generating, and not generalizable due to the small sample size and potential practice effects from repeated testing.