The Role of Sleep in Retention of New Words in Habitually and Non-Habitually Napping Children

Exploring the Relationship Between Age at Nap Cessation and Social-Emotional Functioning in Children

OBJECTIVE

The objective of this study was to examine variations in age at nap cessation and identify whether there is an association with social-emotional functioning (SEF) as measured by internalizing/externalizing behavior, child temperament, and social skills in a sample of early childhood education and care-attending children.

METHODS

The sample comprised 1117 children from the Australian Effectiveness Early Educational Experiences for Children longitudinal early childhood study. We used children's age at nap cessation as retrospectively recalled by caregivers in 2011 or 2013 when children were between ages 2 and 7 years. Each child's SEF was reported by a caregiver using the Strengths and Difficulties Questionnaire, the Short Temperament Scale for Children, and the Social Skills Inventory Scale. Associations between children's age of nap cessation and SEF were tested using linear regressions.

RESULTS

The children's age at nap cessation ranged from 6 months to 6 years. For each additional year of napping, children's total , conduct , externalizing , and peer behavior problems decreased by 0.39 (95% confidence interval [CI], -0.70 to -0.09), 0.11 (95% CI, -0.21 to -0.01), 0.11 (95% CI, -0.51 to -0.06), and 0.11 (95% CI, -0.20 to -0.02) units on the Strengths and Difficulties Questionnaire scale, respectively. No further significant associations were found.

CONCLUSION

This is the first study reporting the age range of nap cessation and its associations with social-emotional functioning. Our findings demonstrate earlier cessation ages in Australian children attending Early Childhood Education and Care programs than previously reported and a small association with externalizing and peer problems.

Contributions of memory and brain development to the bioregulation of naps and nap transitions in early childhood

The transition from multiple sleep bouts each day to a single overnight sleep bout (i.e., nap transition) is a universal process in human development. Naps are important during infancy and early childhood as they enhance learning through memory consolidation. However, a normal part of development is the transition out of naps. Understanding nap transitions is essential in order to maximize early learning and promote positive long-term cognitive outcomes. Here, we propose a novel hypothesis regarding the cognitive, physiological, and neural changes that accompany nap transitions. Specifically, we posit that maturation of the hippocampal-dependent memory network results in more efficient memory storage, which reduces the buildup of homeostatic sleep pressure across the cortex (as reflected by slow-wave activity), and eventually, contributes to nap transitions. This hypothesis synthesizes evidence of bioregulatory mechanisms underlying nap transitions and sheds new light on an important window of change in development. This framework can be used to evaluate multiple untested predictions from the field of sleep science and ultimately, yield science-based guidelines and policies regarding napping in childcare and early education settings.

Relationships between screen viewing and sleep quality for infants and toddlers in China: A cross-sectional study

AIM

Currently young children have more opportunity to access all kinds of media, while their sleep duration has been steadily decreasing. However, little is known about the relationships between screen viewing and sleep quality, and the reasons of screen viewing for children under three years old in China. This study aimed to describe the relationships between screen viewing and sleep quality of infants and toddlers in mainland China.

METHODS

A cross-sectional study was conducted. Eight hundred twenty-seven children were recruited at a health care unit from a university affiliated hospital in China, and the questionnaires were completed by their parents. An extended Brief Infant Sleep Questionnaire and a Screen Viewing Questionnaire were used to collect information on children's sleep quality and screen viewing. Multivariate linear regression models were used to assess the relationships between screen viewing and sleep quality among infants and toddlers, adjusted for sociodemographic variables.

RESULTS

Of the 827 children, 26.9% of the infants and 61.4% of the toddlers did not comply with the World Health Organization (WHO) guideline on screen time. Even after adjusting for the sociodemographic covariates for both infants and toddlers, negative relationships between screen time and total sleep time (P < 0.001), and screen time and nighttime sleep (P < 0.001) existed. TV viewing time was negatively related to infants' total sleep time (β = -0.15, P < 0.001) and toddlers' nighttime sleep (β = -0.1, P < 0.05). Smartphone viewing time was negatively related to toddlers' total sleep time (β = -0.12, P < 0.05) and daytime sleep (β = -0.22, P < 0.05). Parents who offered screen media for children when they needed to do house chores were more likely to report that their children had less total sleep time (β = -0.1, P < 0.05) and shorter longest sleep episode (β = -0.1, P < 0.05).

CONCLUSION

The majority of toddlers did not meet the WHO guidelines on screen time in China. Screen time was negatively related to total sleep time and nighttime sleep among infants and toddlers. Practical strategies, such as education programs on children's screen viewing, more outdoor exercises and indoor parent-child activities, providing other educational materials instead of screening, early sleep, restricted use of TVs and smartphones, and screen co-viewing, are needed to improve young children's sleep quality and promote their development.