A longitudinal study of sleep-wake patterns during early infancy using proposed scoring guidelines for actigraphy

Objective/Background: We describe developmental and day-to-night sleep patterns across the first six months of life using actigraphy and compare these to mother-reported perceptions of infant sleep. Patients/Methods: This observational, burst design included three, one-week bursts of data collection at six, 15, and 24 weeks of age. Infants wore an actigraphy device (Actiwatch Spectrum) on their right ankle for each one-week period. Data were scored using a SAS-based hierarchical, algorithmic methodology and independently assessed for necessary corrections by two trained scorers in a Visual Basic. Mothers completed the Brief Infant Sleep Questionnaire (BISQ) at each burst. Mixed models tested developmental patterns over time and multilevel models examined day-to-night sleep patterns at each burst. Results: Daytime nap sleep duration decreased over time (p = 0.02) with marginal significance for nighttime sleep interval duration increasing over time (p = 0.09). Total 24-h sleep duration was time invariant (p > 0.05). These longitudinal patterns were similar when examining mothers' perception of infant sleep. Daily variations demonstrated nighttime sleep interval and maintenance efficiency did not predict next-day nap sleep duration. Yet, at 24 weeks of age, daytime nap sleep was associated with that nights' sleep interval. For every 1-h above infants' average total daytime nap sleep duration, infants slept similar to 15 min longer and 1.0% less efficiently that night (p <= 0.05). Mothers overestimated daytime nap sleep and total 24-h sleep, when compared to actigraphy (p < 0.01). Conclusion: Changes to infants' usual daytime sleep duration impacted subsequent sleep bouts and mothers tended to overestimate infants' sleep. These patterns should be explored in relation to parenting practices. (C) 2019 Elsevier B.V. All rights reserved.