Development of sleep–wake rhythms during the first year of age

Abstract

Circadian rhythms refer to biological rhythms that have an endogenous period length of approximately 24 hr. However, not much is known about the variance in the development of the sleep-wake rhythm. The study objectives were (a) to describe the normative variation in the development of a sleep-wake rhythm in infancy, (b) to assess whether slower development is related to sleep quality and (c) to evaluate factors that are related to the slower development of a sleep-wake rhythm. The study is based on a representative birth cohort. Questionnaires at the ages of 3 (n = 1,427) and 8 months (n = 1,302) and actigraph measurement at 8 months (n = 372) were available. Infants with significant developmental delays (n = 11) were excluded. The results are based on statistical testing and multivariate modelling. We found that the average percentage of daytime sleep was 36.3% (standard deviation [SD], 8.5%) at 3 months and 25.6% (SD, 6.6%) at 8 months. At both time-points, infants with slower sleep-wake rhythm development slept more hours per day, had a later sleep-wake rhythm, more difficulties in settling to sleep and longer sleep-onset latency; they also spent a longer time awake during the night. According to actigraph registrations, we found that the infants with slow development of a sleep-wake rhythm slept less and had a later start and end to night-time sleep than the other infants. Infants' sleep-wake rhythm development is highly variable and is related to parent-reported and objectively measured sleep quality and quantity. Interventions to improve the sleep-wake rhythm might improve sleep quality in these infants. K E Y W O R D Sinfant, sleep, sleep-wake rhythms

Normal sleep development in infants: findings from two large birth cohorts

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Sleep During Infancy, Inhibitory Control and Working Memory in Toddlers: Findings from the FinnBrain Cohort Study

“…age) (Paavonen et al, 2020;Weissbluth, 1995), and most of the infants sleep an average of two hours during daytime. Interestingly, one recent longitudinal study reported that inappropriate amounts of daytime sleep were related to worse quality of night-time sleep in three to eight-month-old infants (Paavonen et al, 2019). Therefore, it is likely that infants with average amounts of daytime sleep most likely represent the normal ranges of the developmental stage also in other areas of development, such as cognition and/or self-regulation.…”

An Open Source Classifier for Bed Mattress Signal in Infant Sleep Monitoring

“…The gold standard in short-term infant sleep studies is polysomnography (PSG), a non-invasive technique that combines a large set of physiological signals, recorded overnight, to generate an assessment of sleep behavior ( Grigg-Damberger et al, 2007 ). For long-term studies, infant sleep behavior is assessed with sleep diaries and questionnaires ( Sadeh, 2004 ; Paavonen et al, 2019 ). Recent work has also used wrist- or ankle-worn actigraphy ( Sadeh, 2011 ; Paavonen et al, 2019 ) to provide rough assessments of sleep-wake cycles.…”

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