Relations between physiological and cognitive regulatory systems: infant sleep regulation and subsequent executive functioning

Executive Functions and Social-Emotional Problems in Toddlerhood: Nature, Persistence, and Direction of Associations

Social-emotional problems can emerge as early as the first years of life and are associated with a broad range of negative outcomes throughout the lifespan. There is convincing evidence that poorer executive functions (EF) are associated with more social-emotional problems during childhood and adolescence. However, the nature, persistence, and direction of the associations between different components of EF and social-emotional problems in toddlerhood remain unclear. Using two complementary statistical approaches, the present study aimed to (a) identify the role of EF components (inhibitory control, cognitive flexibility, and working memory) in the emergence and maintenance of social-emotional problems during toddlerhood, and (b) explore potential bidirectional associations between toddlers' EF and social-emotional problems. EF and social-emotional problems were assessed around 13, 19, and 28 months of age in a sample of 133 typically developing toddlers (51% boys) from mostly White middle-class families. At each time point, EF were measured with three behavioral tasks and social-emotional problems with a well-validated questionnaire completed by mothers. Multilevel growth models revealed a significant increase in social-emotional problems across toddlerhood and a negative association between inhibitory control and social-emotional problems that persisted across time. Controlling for stability across time, cross-lagged panel models indicated that child inhibitory control at 19 months negatively predicted child social-emotional problems at 28 months, but not the reverse. This study highlights that toddlerhood is a period of significant increase in social-emotional problems and provides evidence for the protective role of early inhibitory control skills against the development of social-emotional problems during toddlerhood.

Actigraphy-assessed sleep duration and quality and executive function in a sample of typically developing preschoolers

Sleep is essential for cognitive development and brain maturation during early childhood. Studies focused on preschool populations using objective measures of sleep are still scarce. The objective of this study was to examine the associations between objective measures of sleep duration and quality with executive functioning in a 133 non-clinical sample of Spanish participants (Mage = 60.33 months, SD = 9.04; ages 41-77 months; 51.1% girls). Sleep was assessed for five weeknights using actigraphy; Shape School task was applied to assess inhibition and cognitive flexibility; and Word Span task was used to assess working memory. The results revealed that relation between sleep and executive functioning was significant for inhibition and working memory. Preschoolers with higher sleep efficiency showed better results in executive functioning tasks after controlling for the effect of age. Additionally, age and sleep duration and quality variables were predictive of inhibition, working memory, and cognitive flexibility. These results suggest that the different dimensions of sleep could play an important role in the development of executive functions during preschool age. Therefore, improving sleep could lead to an improvement in children's executive functioning in both clinical and educational contexts.

The Association Between Infant Sleep, Cognitive, and Psychomotor Development: A Systematic Review

STUDY OBJECTIVES

To synthesize findings of original articles examining the association between sleep-wake patterns of typically developing infants aged 0-to-18 months and cognitive and psychomotor development.

METHODS

A systematic search strategy was used to identify articles assessing the association between infant sleep (0-to-18 months) and cognitive/psychomotor development (Medline, PsycINFO, SCOPUS). Of 7,136 articles screened, 22 articles met inclusion criteria, and the results were subsequently synthesized. A quality assessment was conducted, and studies were categorized as "poor", "fair", or "good".

RESULTS

Out of 22 studies, two found exclusively significant associations between infant sleep and cognitive/psychomotor development, three found no significant associations and 17 found mixed results. Studies with exclusively significant results used a single sleep variable and single timepoint designs. Studies finding mixed results or no significant associations used multiple sleep, developmental variables, or multi-timepoint designs. Eight out of 10 studies and seven out of eight studies investigating nocturnal and total sleep duration, respectively, found no significant association with developmental outcomes. While 63% of studies were rated as having good methodological quality, all studies but one had estimated power of less than 0.80.

CONCLUSION

Findings of this review do not support conclusive associations between sleep-wake patterns in infancy and cognitive/psychomotor development. This conclusion contrasts with the literature in older populations, questioning if the association between sleep and development is of a different nature in infancy, potentially because of brain maturation. More studies including larger samples will be needed to clarify the presence or absence of such an association.

Infants' early recovery from sleep disturbance is associated with a lower risk of developmental delay in the Japan Environment and Children's Study

To examine whether patterns, such as the timings of onset or recovery from sleep disturbance, are associated with later developmental problems, including autism spectrum disorder (ASD). Mothers participating in the Japan Environment and Children's Study with a child aged 3 years were included in the analyses. Children were assessed for short sleep and frequent awakenings at 1 month, 6 months, and 1 year of age. Developmental problems were evaluated at 3 years of age based on ASD diagnosis and developmental delay, using the Japanese translation of the Ages and Stages Questionnaire (ASQ) 3rd edition. Sleep disturbance patterns were classified by onset age, and developmental problem risks were examined based on onset/recovery ages. Among 63,418 mother-infant dyads, 0.4% of infants were later diagnosed with ASD, and 14.4% had abnormal scores on any ASQ domains. The later the onset of short sleep, the lower the risk of abnormal ASQ scores (RR of short sleep onset at 1 year: 1.41; 6 months: 1.52; 1 month: 1.57). The earlier the infants recovered from short sleep persistence, the lower the risk of developmental delay (RR of remittance of sleep problems identified at 1 month by 6 months: 1.07; 1 year: 1.31; not before 1 year: 1.57). Although not all patterns were significant, later short sleep onset and earlier recovery were associated with lower ASD risk. These findings may have significant implications for future interventions in infant development.

Daytime sleep duration during infancy as an indicator for cognitive development at school age: a prospective cohort study

STUDY OBJECTIVES

The reduction in daytime sleep during early life is considered one of the indicators of the maturation of sleep patterns, which is closely associated with cognitive development. The current study aims to analyze the relationships between daytime sleep duration (DSD) during infancy and cognitive development at 6 and 10 years.

METHODS

The study included 262 mothers with their newborns from the Shanghai Sleep Birth Cohort Study, spanning 11 follow-ups from 42 days to 10 years. Sleep parameters were assessed using parent-reported questionnaires at each follow-up, and cognitive development was evaluated with the Wechsler Intelligence Scale for Children, fourth edition at 6 and 10 years.

RESULTS

Two distinct DSD trajectories in early childhood were identified: "typical DSD" (66.7%) and "infancy excessive DSD" (33.3%). Children in the "infancy excessive DSD" trajectory exhibited lower working memory scores than those in the "typical DSD" trajectory at 6 years (mean difference = 5.90, 95% confidence interval [1.83, 9.96], P = .005) and 10 years (mean difference = 4.37, 95% confidence interval [0.26, 8.48], P = .037). Additional analysis in a relatively homogeneous sample consistently showed correlations between DSD trajectories and working memory performance. No consistent significant differences were found in other domains of cognitive development.

CONCLUSIONS

Excessive daytime sleep during infancy may serve as an early indicator for poor working memory at school age. These findings raise concerns about the long-term cognitive development of infants with excessive DSD.

CITATION

Lin J, Jiang Y, Xiao X, et al. Daytime sleep duration during infancy as an indicator for cognitive development at school age: a prospective cohort study. J Clin Sleep Med. 2024;20(7):1069-1077.

Early childhood sleep quantity, but not caregiver-reported sleep problems, predicts impulse control in children at age 8 years

Short duration of sleep and poor sleep quality have been linked to poor attention and impulse control in children. We aimed to determine the longitudinal predictive value of sleep quantity and quality during early childhood on objective and caregiver-report measures of attention, impulse control, and executive function in children at age 8 years. We used data from the Health Outcomes and Measures of the Environment (HOME) Study, a pregnancy and birth cohort. Caregivers reported on their child's sleep at ages 2, 2.5, 3, 4, and 5 years. Analysis included 410 participants. We used longitudinal growth curve models of early childhood sleep patterns to predict neurobehavioral functioning at age 8 years. Sleep problems did not predict any of our outcome measures at age 8 years. Sleep duration trended shorter as children matured, so predictive models examined both intercept and slope. Children with the least decline in sleep duration across early childhood had fewer impulsive errors at age 8 years on a continuous performance test (unadjusted p = .013; adjusted p = .013). Children with shorter duration of sleep across early childhood had worse caregiver-reported behavioral regulation at age 8 years (unadjusted p = .002; adjusted p = .043). Neither sleep duration slope nor intercept predicted inattention or metacognitive skills at age 8 years (p > .05). Total sleep time across early childhood predicts behavior regulation difficulties in school-aged children. Inadequate sleep during early childhood may be a marker for, or contribute to, poor development of a child's self-regulatory skills.

Carer-reported sleep disturbance and carer- and teacher-rated executive functioning in children with prenatal alcohol exposure and Fetal Alcohol Spectrum Disorder

Children with prenatal alcohol exposure (PAE) and Fetal Alcohol Spectrum Disorder (FASD) have high rates of sleep disturbance and marked difficulties with executive functioning (EF). Sleep disturbance has been associated with poorer EF across development in typically developing children. The contribution of insomnia symptoms and nightmares to EF difficulties in children with PAE and FASD is unclear. The current study examined whether caregiver-reported insomnia symptoms and nightmares predicted difficulties with EF in children with PAE who were assessed at FASD diagnostic clinics. Archival data on 116 children with PAE assessed at FASD diagnostic clinics were extracted from databases. Children were assigned to a preschool-age group (3.1 to 5.9 years, n = 40) and a school-age group (5.9 to 10.9 years, n = 76). Insomnia symptoms and nightmares were measured using items extracted from the Child Behavior Checklist (CBCL) while EF was measured using the caregiver and teacher Behavior Rating Inventory of Executive Function (BRIEF) rating forms. Bootstrapped regression models were used examine the effects of insomnia symptoms and nightmares on domains of EF in each group while adjusting for potential confounds. For preschool children, insomnia symptoms were associated with greater daytime tiredness while nightmares were associated with greater difficulties with Emergent Metacognition according to their teachers. For school-age children, insomnia symptoms predicted greater EF difficulties across most domains according to their caregivers but not teachers. Sleep disturbance may compound EF impairments in children with PAE and should be screened for as part of FASD diagnostic assessment.

The Associations Between Sleep and Externalizing and Internalizing Problems in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: Empirical Findings, Clinical Implications, and Future Research Directions

Sleep problems are common in youth with attention-deficit/hyperactivity disorder (ADHD). Externalizing and internalizing problems contribute to dysfunction in youth with ADHD and are amplified by disrupted sleep. This objective of this article is to synthesize empirical studies that examined the associations between sleep and internalizing or externalizing problems in individuals with ADHD. The main findings are that sleep problems precede, predict, and significantly contribute to the manifestation of internalizing and externalizing behavior problems among children and adolescents with ADHD. Clinicians should assess sleep and integrate sleep interventions into the management of youth with ADHD.

Maternal Perceptions of Evidence-Based Early Childhood Sleep Health Promotion Recommendations: An Explanatory Sequential Study

OBJECTIVES

The purpose of this explanatory sequential design study was to better understand caregivers' perceptions about and interest in evidence-based early childhood sleep health promotion recommendations.

METHOD

A purposeful sample of mothers of 20 1-5-year-old children (10 children exhibiting optimal sleep and 10 children exhibiting insufficient/fragmented sleep) attending a preschool serving a low socio-economic (SES) status metropolitan community were invited to participate in qualitative interviews. Data were coded according to a grounded theory approach and themes were identified within the optimal and suboptimal sleeper groups.

RESULTS

Mothers reported different approaches to managing electronics by optimal/suboptimal sleeper group, with mothers of optimal sleepers limiting access to electronics more than mothers in the suboptimal sleep group. Other themes of sleep health practices did not differ meaningfully between groups.

CONCLUSIONS

Maternal perspectives about early childhood sleep health were similar across optimal and suboptimal sleepers on most elements of child sleep health. Managing child sleep was contextually influenced and these results highlight the complexities of how families living in lower SES environments perceive common sleep recommendations. Thus, sleep health education efforts should be tailored to the needs and values of specific families and communities.

Association of physical activity and fitness with executive function among preschoolers

It is well-documented in the literature that high levels of regular physical activity (PA), low levels of sedentary behavior (SB), and high levels of cardiorespiratory fitness (CRF) are associated with superior cognitive functioning, especially with regard to older populations. However, concerning other age groups (e.g., preschoolers) the available evidence documenting such a positive relationship is relatively scarce. Thus, this study aimed to investigate the association of time spent in different PA intensity zones and CRF with executive functions (EFs) in preschool-age children. To this end, preschoolers (n = 127) aged 3 to 6 years were recruited from 9 kindergarten classes in 2 districts of Shenzhen, China. The amount and the intensity of PA were assessed via accelerometry, and the CRF level was quantified by the 20-meter shuttle run test. EFs including inhibitory control and working memory were assessed using the one-on-one iPad-based Early Year Toolbox. Results suggested that children who had a higher CRF level ("impulse control" scores: β = 0.34, p < .001; "Go" accuracy: β = 0.31, p < .001; "No-Go" accuracy: β =0.28, < .001) and spentmore time in moderate-to-vigorous physical activity (MVPA) ("impulse control" scores: β = 0.50, p < .001; No-Go" accuracy: β = 0.52, p < .001) had higher scores on inhibitory control tasks, and those who had a higher CRF level had higher scores on a working memory task (β = 0.24, p < .05). The findings are discussed in light of the positive roles of MVPA and CRF for promoting EFs, but also consider the disproportionate association of PA and CRF with working memory relative to inhibition.

Early Sleep Differences in Young Infants with Autism Spectrum Disorder

OBJECTIVE

Children with autism spectrum disorder (ASD) experience greater sleep challenges than their neurotypical peers, but sleep patterns for infants later diagnosed with ASD are unknown. This study examined differences in total sleep duration and proportion of sleep experienced at night within the first 6 months of life among infants later diagnosed with ASD, infants who demonstrated subclinical characteristics of ASD and were classified as exhibiting the broad autism phenotype (BAP), and their typically developing (TD) peers. In addition, associations between infant sleep variables and developmental outcomes at 24 months were explored.

METHODS

Participants included 79 infants enrolled in a prospective, longitudinal study of the early development of ASD. Between ages 1 week and 6 months, participants completed a monthly retrospective 24-hour sleep log. At 24 months, participants received a comprehensive diagnostic evaluation, including the Autism Diagnostic Observation Schedule-2 and Mullen Scales of Early Learning and Vineland-II and were clinically characterized as ASD, BAP, or TD.

RESULTS

When accounting for the influence of age, infants later diagnosed with ASD slept less within the 24-hour period than infants in TD or BAP groups from 0 to 6 months ( p = 0.04). Percentage of sleep experienced during nighttime hours did not significantly differ between groups from 0 to 6 months ( p = 0.25). Greater nighttime sleep percentage at 6 months predicted higher receptive language ( p < 0.001) and fine motor scores ( p < 0.0001) at 24 months. Total sleep duration at 6 months did not predict any developmental outcomes at 24 months.

CONCLUSION

Findings suggest that differences in sleep may occur among autistic individuals earlier in life than previously documented and have cascading effects on development.

The impact of extreme summer temperatures in the United Kingdom on infant sleep: Implications for learning and development

The U.S. Global Change Research Program reports that the frequency and intensity of extreme heat are increasing globally. Studies of the impact of climate change on child health often exclude sleep, despite its importance for healthy growth and development. To address this gap in the literature, we studied the impact of unusually high temperatures in the summer of 2022 on infants' sleep. Sleep was assessed objectively using Nanit camera monitors in infants' homes. Generally, sleep was not impacted when temperatures stayed below 88° but was negatively impacted when temperatures reached over 100°. Compared to non-heatwave nights, infants had less total sleep, less efficient sleep, took longer to fall asleep, had more fragmented sleep, and parents' visits were more frequent during the night. Following peaks in temperature, sleep metrics rebounded to better than average compared to non-peak nights, suggesting that infants compensated for disrupted sleep by sleeping more and with fewer interruptions once the temperature dropped below 85°. Increased instances of disrupted sleep in infancy have important implications for psychological health and development. Climate disruptions such as heat waves that create occasional or ongoing sleep disruptions can leave infants vulnerable and unprepared for learning.

Universality and context-specificity in early executive function development

A renewed interest in early executive function (i.e., EF or the conscious control of thought and behavior) development has led several research groups to suggest that EF may be emerging and is less coordinated (e.g., showing few relations between tasks) in the first few years (Devine et al., 2019; Gago Galvagno et al., 2021; Johansson et al., 2016; Miller & Marcovitch, 2015; Ribner et al., 2022). This potentially universal development in EF does not exclude the possibility that EF may also differ across context (e.g., Gago Galvagno et al., 2021; Lohndorf et al., 2019; Tran et al., 2015) reflecting unique strengths and development built within one's sociocultural environment. The present paper explores potential universal and context-specific early EF developments by focusing on three aims: (1) reviewing work on EF within the first two years of life that may speak to potential universality in the measurement, structure, growth, stability, and conceptualization of early EF (2) reviewing research that may speak to how the sociocultural context may play a role in context-specific development within early EF and (3) examining potential developmental EF frameworks for understanding universal and context-specific developments of early EF within context.

The relationship between parents' cognitions, bedtime behaviours and sleep-related practices with their child's sleep

Certain parental cognitions about child sleep and bedtime behaviours used with their child have been linked to poorer child sleep. However, previous research has focused on mothers and explored only a limited range of sleep-related cognitions and practices. The present study investigated whether parental cognitions and sleep-related practices (both in connection with their own sleep and their child's sleep), alongside the bedtime behaviours used with their child were associated with and/or were predictive of their child's sleep. Mothers and fathers from 44 families (with a child aged 12-24 months) separately completed questionnaires reporting (i) their cognitions (about their own sleep and their child's sleep), (ii) sleep-related practices (used in connection with their own and their child's sleep) and (iii) bedtime behaviours used with their child. Child sleep was assessed through parental report and actigraphy. Both parents' cognitions about their own sleep predicted cognitions about their child's sleep. Mothers' own sleep-related practices predicted the types of practices they used with their child. Different patterns of maternal and paternal variables influenced parental perceptions of their child having a sleep problem. The present findings highlight the importance of including mothers and fathers in child sleep research. Parents' dysfunctional cognitions (their own sleep) and broader sleep-related practices (their own and child sleep) should be considered when exploring influences on child sleep. Results have possible implications for targets of interventions for child sleep problems and also potential implications for theoretical models of child sleep.

Trajectories of reported sleep duration associate with early childhood cognitive development

STUDY OBJECTIVES

Examine how different trajectories of reported sleep duration associate with early childhood cognition.

METHODS

Caregiver-reported sleep duration data (n = 330) were collected using the Brief Infant Sleep Questionnaire at 3, 6, 9, 12, 18, and 24 months and Children's Sleep Habits Questionnaire at 54 months. Multiple group-based day-, night-, and/or total sleep trajectories were derived-each differing in duration and variability. Bayley Scales of Infant and Toddler Development-III (Bayley-III) and the Kaufman Brief Intelligence Test- 2 (KBIT-2) were used to assess cognition at 24 and 54 months, respectively.

RESULTS

Compared to short variable night sleep trajectory, long consistent night sleep trajectory was associated with higher scores on Bayley-III (cognition and language), while moderate/long consistent night sleep trajectories were associated with higher KBIT-2 (verbal and composite) scores. Children with a long consistent total sleep trajectory had higher Bayley-III (cognition and expressive language) and KBIT-2 (verbal and composite) scores compared to children with a short variable total sleep trajectory. Moderate consistent total sleep trajectory was associated with higher Bayley-III language and KBIT-2 verbal scores relative to the short variable total trajectory. Children with a long variable day sleep had lower Bayley-III (cognition and fine motor) and KBIT-2 (verbal and composite) scores compared to children with a short consistent day sleep trajectory.

CONCLUSIONS

Longer and more consistent night- and total sleep trajectories, and a short day sleep trajectory in early childhood were associated with better cognition at 2 and 4.5 years.

The Architecture of Early Childhood Sleep Over the First Two Years

INTRODUCTION

The architecture and function of sleep during infancy and early childhood has not been fully described in the scientific literature. The impact of early sleep disruption on cognitive and physical development is also under-studied. The aim of this review was to investigate early childhood sleep development over the first two years and its association with neurodevelopment.

METHODS

This review was conducted according to the 2009 PRISMA guidelines. Four databases (OVID Medline, Pubmed, CINAHL, and Web of Science) were searched according to predefined search terms.

RESULTS

Ninety-three studies with approximately 90,000 subjects from demographically diverse backgrounds were included in this review. Sleep is the predominant state at birth. There is an increase in NREM and a decrease in REM sleep during the first two years. Changes in sleep architecture occur in tandem with development. There are more studies exploring sleep and early infancy compared to mid and late infancy and early childhood.

DISCUSSION

Sleep is critical for memory, learning, and socio-emotional development. Future longitudinal studies in infants and young children should focus on sleep architecture at each month of life to establish the emergence of key characteristics, especially from 7-24 months of age, during periods of rapid neurodevelopmental progress.

Sleep Patterns in Young Children with Congenital Heart Disease

Sleep patterns of 419 toddlers with congenital heart disease were comparable with the normative population except for increased likelihood across the cohort of sleeping in parents' room and increased disrupted sleep in children aged 18-23 months. Disrupted sleep patterns were associated with lower maternal education and increased medical complexity.

The Mediatory Role of Executive Functioning on the Association Between Sleep and Both Everyday Memory and ADHD Symptoms in Children and Youth With Down Syndrome

People with Down syndrome (DS) commonly experience challenges with sleep, executive functioning, everyday memory, and symptoms of attention deficit hyperactivity disorder (ADHD). A path analysis was conducted to determine if executive function mediated the relationship between sleep problems and both everyday memory and ADHD symptoms. Parents of 96 children and youth with DS completed questionnaires related to sleep, executive functioning, everyday memory, and ADHD symptoms. Results showed that executive functioning fully mediated the relation between sleep and both everyday memory and ADHD symptoms. Implications for education and intervention for children and youth with DS are discussed.

Links between Daytime Napping, Night-Time Sleep Quality and Infant Attention: An Eye-Tracking, Actigraphy and Parent-Report Study

The current study explored the potential influence of infant sleep, measured by parental report and actigraphy, and family functioning on attention development using eye tracking. The use of actigraphy in parallel with parental report, has the advantage of measuring participant’s sleep throughout the night without parental observation and the ability to objectively assess sleep quality. An eye-tracking version of the Gap-Overlap task was used to measure visual attention. Questionnaires and behavioural assessment were used to assess family function, and general cognitive development. Fifty infants (Mean age = 13.44 months, SD = 3.10) participated in the study, 23 of which had full final datasets. Results show that daytime sleep duration, as measured by parental report, and proportion of light sleep at night, as measured by actigraphy, are linked to visual attention. A higher proportion of light sleep, a marker of poorer sleep quality, and less daytime sleep were negatively linked with facilitation and disengagement on the Gap-Overlap task. Family functioning was not associated with attention. The results provide initial evidence that in addition to the amount of daytime sleep; quality of night-time sleep as measured by proportion of light sleep, is a potentially useful sleep variable which requires further focus in the study of attention development.

Sleep disturbances in infants and young children following an acquired brain injury

STUDY OBJECTIVES

Sleep disturbances impact over half of older children and teens with acquired brain injury (ABI) following critical care hospitalization but are underevaluated in infants and young children. Given the importance of sleep in brain development and healing after injury, we hypothesized sleep disturbances would be associated with worse neurodevelopmental outcomes in infants with ABI.

METHODS

We performed a retrospective cohort study of 68 children aged 2-32 months following critical care hospitalization for ABI. The Brief Infant Sleep Questionnaire assessed sleep disturbances. Bayley Scales of Infant and Toddler Development, third edition and Adaptive Behavior Assessment System, third edition assessed developmental and adaptive functioning outcomes, respectively. t tests compared sleep characteristics in infants with ABI to historical healthy controls. Spearman's correlation evaluated relationships among sleep and outcomes. Multiple linear regression investigated relationships controlling for demographic and ABI characteristics.

RESULTS

Compared to healthy controls, children with ABI had shorter nighttime sleep duration (P = .01), longer daytime sleep duration (P < .001), and longer duration of nighttime awakenings (P < .001). Duration of night awakenings negatively correlated with Bayley Cognitive scores (Spearman's correlation = -.40). Night awakenings negatively correlated with worse Adaptive Behavior Assessment System, third edition General Adaptive Composite scores (Spearman's correlation = -.42). When controlling for demographic and ABI characteristics, ≥ 3 awakenings was significantly associated with worse Adaptive Behavior Assessment System, third edition General Adaptive Composite (β = -11.3; 95% confidence interval = -19.2, -3.5).

CONCLUSIONS

Sleep disturbances are associated with poorer outcomes in infants and toddlers after ABI. Sleep is vital to recovery and a potentially modifiable target to improve outcomes.

CITATION

Klapp JM, Hall TA, Riley AR, Williams CN. Sleep disturbances in infants and young children following an acquired brain injury. J Clin Sleep Med. 2022;18(10):2387-2395.

The Brain and Early Experience Study: Protocol for a Prospective Observational Study

BACKGROUND

Children raised in conditions of poverty (or near poverty) are at risk for nonoptimal mental health, educational, and occupational outcomes, many of which may be precipitated by individual differences in executive function (EF) skills that first emerge in early childhood.

OBJECTIVE

The Brain and Early Experience study considers prenatal and postnatal experiences that may mediate the association between poverty and EF skills, including neural substrates. This paper described the study rationale and aims; research design issues, including sample size determination, the recruitment strategy, and participant characteristics; and a summary of developmental assessment points, procedures, and measures used to test the study hypotheses.

METHODS

This is a prospective longitudinal study examining multiple pathways by which poverty influences normative variations in EF skills in early childhood. It is funded by the National Institute of Child Health and Human Development and approved by the institutional review board.

RESULTS

Recruitment is complete with a sample of 203 participants, and data collection is expected to continue from September 2018 to February 2024. Of those recruited as low socioeconomic status (SES), 71% (55/78) reported income-to-needs (ITN) ratios of <2.0, and 35% (27/78) reported ITN ratios of <1.0. Among participants recruited into the not-low SES stratum, only 8.8% (11/125) reported ITN ratios of <2.0, and no participant reported ITN ratios of <1.0. The average ITN ratio for participants recruited into the low-income stratum was significantly lower than the average for the high-income recruitment cell (P<.001). Comparable recruitment outcomes were observed for both Black and non-Black families. Overall, the sample has adequate diversity for testing proposed hypotheses, with 13.3% (27/203) of participants reporting ITN ratios of <1 and >32.5% (66/203) reporting ratios of <2.0.

CONCLUSIONS

Preliminary results indicate that the recruitment strategy for maximizing variation in family SES was successful, including variation within race. The findings of this study will help elucidate the complex interplay between prenatal and postnatal risk factors affecting critical neurocognitive developmental outcomes in early childhood.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/34854.

Associations of sleep characteristics with cognitive and gross motor development in toddlers

OBJECTIVE

To examine cross-sectional associations of sleep characteristics (duration, consolidation, timing, variability) with cognitive and gross motor development in toddlers.

METHODS

Participants were 205 toddlers (19.6 ± 4.3 months) from the GET-UP!

STUDY

Nap/nighttime sleep onset and offset were measured using an accelerometer and used to calculate nap/nighttime sleep duration. Total sleep duration was calculated and classified as meeting or not meeting the sleep recommendation of the Australian 24-Hour Movement Guidelines (11-14 h/d). Nighttime sleep ratio (ie, nighttime sleep duration: total sleep duration), indicative of consolidation, was expressed as a percent value. Nighttime sleep midpoint (ie, the midpoint between nighttime sleep onset and offset), indicating the lateness of sleep schedules, was converted to a decimal hour. For sleep variability, the intraindividual standard deviation of nighttime sleep duration and nighttime sleep midpoint was calculated, respectively. Cognitive development (Bayley Scales of Infant and Toddler Development-III) and specific domains of gross motor development (Peabody Developmental Motor Scales, 2nd edition) were measured.

RESULTS

Shorter nap duration (B = -0.87, 95%CI: -1.71, -0.02) and higher nighttime sleep ratio (B = 0.13, 95% CI: 0.02, 0.24) were associated with better cognitive development. Regarding gross motor development, positive associations were found for nighttime sleep duration (object manipulation: B = 0.26, 95% CI: 0.01, 0.51; gross motor quotient: B = 1.21, 95% CI: 0.04, 2.38) and total sleep duration (object manipulation: B = 0.28, 95% CI: 0.03, 0.52); negative associations were found for nighttime sleep midpoint (stationary: B = -0.31; 95% CI: -0.58, -0.06) and nighttime sleep duration variability (stationary: B = -0.32, 95% CI: -0.64, -0.004).

CONCLUSIONS

In toddlers, more consolidated sleep may be an indicator of better cognitive development. Promoting longer and more consistent nighttime sleep duration, as well as an earlier nighttime sleep schedule, may facilitate gross motor development. However, our findings for the associations of sleep characteristics with cognitive and gross motor development need to be confirmed in prospective studies.

Early life circadian rhythm disruption in mice alters brain and behavior in adulthood

Healthy sleep supports robust development of the brain and behavior. Modern society presents a host of challenges that can impair and disrupt critical circadian rhythms that reinforce optimal physiological functioning, including the proper timing and consolidation of sleep. While the acute effects of inadequate sleep and disrupted circadian rhythms are being defined, the adverse developmental consequences of disrupted sleep and circadian rhythms are understudied. Here, we exposed mice to disrupting light–dark cycles from birth until weaning and demonstrate that such exposure has adverse impacts on brain and behavior as adults. Mice that experience early-life circadian disruption exhibit more anxiety-like behavior in the elevated plus maze, poorer spatial memory in the Morris Water Maze, and impaired working memory in a delayed match-to-sample task. Additionally, neuron morphology in the amygdala, hippocampus and prefrontal cortex is adversely impacted. Pyramidal cells in these areas had smaller dendritic fields, and pyramidal cells in the prefrontal cortex and hippocampus also exhibited diminished branching orders. Disrupted mice were also hyperactive as adults, but otherwise exhibited no alteration in adult circadian locomotor rhythms. These results highlight that circadian disruption early in life may have long lasting and far-reaching consequences for the development of behavior and the brain.

Not all babies are in the same boat: Exploring the effects of socioeconomic status, parental attitudes, and activities during the 2020 COVID-19 pandemic on early Executive Functions

Early executive functions (EFs) lay the foundations for academic and social outcomes. In this parent-report study of 575 UK-based 8- to 36 month olds (218 followed longitudinally), we investigate how variation in the home environment before and during the 2020 pandemic relates to infants' emerging EFs. Parent-infant enriching activities were positively associated with infant Cognitive Executive Function (CEF) (encompassing inhibitory control, working memory, cognitive flexibility). During the most-restrictive UK lockdown-but not subsequently-socioeconomic status (SES) was positively associated with levels of parent-infant enriching activities. Parents who regard fostering early learning, affection, and attachment as important were more likely to engage in parent-infant enriching activities, yet there was no significant pathway from parental attitudes or SES to CEF via activities. Infant screen use was negatively associated with CEF and Regulation. Screen use fully mediated the effect of SES on CEF, and partially mediated the effect of SES on regulation. Parental attitudes toward early learning, affection, and attachment did not significantly influence screen use. These results indicate that although parental attitudes influence the development of early EFs, interventions targeting attitudes as a means of increasing enriching activities, and thus EF are likely to be less effective than reducing barriers to engaging in enriching activities.

Socioeconomic status and infant nighttime sleep across the second year of life: The moderating role of infant attachment security

This study examined socioeconomic status (SES) and attachment security as predictors of infant nighttime sleep during the second year. Participants included 128 mothers (86% White) with infants (48.4% boys). Data collection took place between April, 2009 and February, 2014. At 12, 18, and 24 months, infant sleep was assessed via actigraphy and daily diaries, and attachment with the Attachment Q-Set. SES indicators included income-to-needs ratios and education. Lower SES predicted greater variability in sleep duration and later sleep timing only for less secure infants. Less secure attachment was associated with poorer sleep at both between- and within-person levels, especially when infants were 12 months of age. Results emphasize the complex interactive effects of environmental and relational factors on infant sleep.

Early executive and school functioning: Protective roles of home environment by income

This study used data from the Family Life Project (N=1,227), a longitudinal study of child development. We tested a three-way interaction in which positive parenting and learning materials in the home from age 6-36 months and family income predicted children's executive functioning (EF) at 58 months. We also tested whether this interaction predicted early school functioning, specifically behavioral and academic skills in the 1^st grade. The interactive effects of positive parenting and learning materials differed by family income. For children in families of lower income, more learning materials and positive parenting predicted better EF, and in turn, better early school functioning. For children in families of higher income, only positive parenting significantly predicted EF, which in turn, predicted better early school functioning. Findings suggest that more targeted policy and program support for enrichment and positive parenting may bolster efforts to combat poverty.

Does the maturation of early sleep patterns predict language ability at school entry? A Born in Bradford study

Children's vocabulary ability at school entry is highly variable and predictive of later language and literacy outcomes. Sleep is potentially useful in understanding and explaining that variability, with sleep patterns being predictive of global trajectories of language acquisition. Here, we looked to replicate and extend these findings. Data from 354 children (without English as an additional language) in the Born in Bradford study were analysed, describing the mean intercepts and linear trends in parent-reported day-time and night-time sleep duration over five time points between 6 and 36 months-of-age. The mean difference between night-time and day-time sleep was predictive of receptive vocabulary at age five, with more night-time sleep relative to day-time sleep predicting better language. An exploratory analysis suggested that socioeconomic status was predictive of vocabulary outcomes, with sleep patterns partially mediating this relationship. We suggest that the consolidation of sleep patterns acts as a driver of early language development.

Parenting and maternal reported child sleep problems in infancy predict school-age aggression and inattention

OBJECTIVE

To examine caregiving predictors of maternal reported sleep problems and child behavioral and cognitive outcomes in early childhood.

DESIGN

A prospective longitudinal study from 6 to 84 months of age.

SETTING

Lab visits, assessments, and questionnaires conducted with a community-based sample.

PARTICIPANTS

One hundred sixty-four African American and White children, their mothers, and teachers.

MEASUREMENT

Parenting behavior was measured during a free-play task at 6 months of age, maternal-report of child sleep problems was completed at 6 timepoints, and teacher report of child aggression and attention was collected in kindergarten and second grade.

RESULTS

Latent growth curve modeling revealed that maternal reported sleep problems decreased in children from 18 to 84 months and harsh-intrusive parenting at 6 months predicted sleep problems at 18 months. Maternal reported sleep problems at 18 months predicted aggressive behaviors in kindergarten and second grade.

CONCLUSION

Parenting at 6 months of age exerts an influence on sleep quality at 18 months which is associated with aggressive behavior in early childhood.

Association between breastfeeding and sleep patterns in infants and preschool children

BACKGROUND

Although most studies have reported unfavorable short-term effects of breastfeeding on early-childhood sleep-wake behaviors that potentially attenuate over time, findings have remained inconsistent.

OBJECTIVES

We assessed associations of breastfeeding with longitudinal day-, night-, and total-sleep trajectories and with sleep-wake behaviors in healthy infants and preschoolers.

METHODS

Caregivers of naturally conceived, term, singleton infants (n = 654) completed the Brief Infant Sleep Questionnaire (3, 6, 9, 12, 18, and 24 mo) and/or Children's Sleep Habits Questionnaire (54 mo), and provided information on their infants' breastfeeding status at 3 mo. Trajectory analyses derived 4 day- (n = 243), 3 night- (n = 248), and/or 4 total- (n = 241) sleep trajectories, each differing in length of sleep duration (short/moderate/long) and variability (variable/consistent). Sleep-wake behaviors from 3 to 24 mo (day/night/total-sleep durations and duration/number of night awakenings) were also assessed for associations with breastfeeding.

RESULTS

After adjusting for potential covariates, formula-fed infants, relative to fully breastfed (predominant or exclusive) infants, were significantly less likely to exhibit moderate (OR: 0.28; 95% CI: 0.11, 0.70) and long consistent (OR: 0.18; 95% CI: 0.07, 0.50) night-sleep trajectories and less likely to exhibit moderate (OR: 0.21; 95% CI: 0.07, 0.61) and long consistent (OR: 0.12; 95% CI: 0.04, 0.38) and long variable (OR: 0.16; 95% CI: 0.05, 0.56) total-sleep trajectories, instead of short variable night- and total-sleep trajectories. Partially breastfed infants did not differ from fully breastfed infants for both night- and total-sleep trajectories. No significant differences were found between all groups for day-sleep trajectories. Fully breastfed infants had longer night- (6, 9, 12, and 24 mo) and total- (3 and 12 mo) sleep durations than formula-fed infants, albeit a greater number of night awakenings (from 6 to 12 mo).

CONCLUSIONS

Despite more night awakenings, fully breastfed infants have overall longer night- and total-sleep durations (sleep trajectories) than formula-fed infants.

Concordance between subjective and objective measures of infant sleep varies by age and maternal mood: Implications for studies of sleep and cognitive development

Infant habitual sleep has been proposed as an important moderator of development in domains such as attention, memory or temperament. To test such hypotheses, we need to know how to accurately and consistently assess habitual sleep in infancy. Common assessment methods include easy to deploy but subjective parent-report measures (diary/sleep questionnaire); or more labour-intensive but objective motor movement measures (actigraphy). Understanding the degree to which these methods provide converging insights is important, but cross-method agreement has yet to be investigated longitudinally. Moreover, it is unclear whether concordance systematically varies with infant or maternal characteristics that could represent confounders in observational studies. This longitudinal study (up to 4 study visits/participant) investigated cross-method concordance on one objective (7-day actigraphy) and three commonly used subjective (7-day sleep diary, Brief Infant Sleep Questionnaire, Sleep & Settle Questionnaire) sleep measures in 76 typically developing infants (age: 4–14 months) and assessed the impact of maternal characteristics (stress, age, education) and infant characteristics (age) on cross-method concordance. In addition, associations between objective and subjective sleep measures and a measure of general developmental status (Ages & Stages Questionnaire) were investigated. A range of equivalence analyses (tests of equivalence, correlational analyses, Bland-Altman plots) showed mixed agreement between sleep measures. Most importantly, cross-method agreement was associated with maternal stress levels and infant age. Specifically, agreement between different measures of night waking was better for mothers experiencing higher stress levels and was higher for younger than older infants; the reverse pattern was true for day sleep duration. Interestingly, objective and subjective measures did not yield the same patterns of association with developmental domains, indicating that sleep method choice can influence which associations are found between sleep and cognitive development. However, results converged across day sleep and problem-solving skills, highlighting the importance of studying day sleep in future studies. We discuss implications of sleep method choice for investigating sleep in the context of studying infant development and behaviour.

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A range of equivalence analyses showed mixed agreement between subjective and objective sleep measures.

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Cross-method agreement was associated with maternal stress levels and infant age.

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Objective and subjective measures did not yield the same patterns of association with developmental domains except for day sleep duration.

Type of Milk Feeding and Introduction to Complementary Foods in Relation to Infant Sleep: A Systematic Review

Inconsistent conclusions from infant sleep and feeding studies may influence parents feeding-related decisions. This study aimed to systematically review the existing literature on infant sleep and its relation to the timing of introduction to complementary foods and type of milk feeding to better understand their role(s) in infant sleep. Cohort, longitudinal, cross-sectional studies, and controlled trials were identified using online searches of five databases up to April 2020. Twenty-one articles with a total of 6225 infants under 12 months-of-age were eligible. Exclusively breastfed infants (≤6 months-of-age) had a greater number of night wakings, but most studies (67%) reported no difference in night-time and 24 h sleep duration compared to formula-fed infants. However, after 6 months-of-age, most studies (>65%) reported breastfed infants to sleep less in the night-time and over 24 h compared to formula-fed infants. Furthermore, studies reported no association between the timing of introduction to complementary foods and infant sleep duration (<12 months-of-age). Future studies using standardized methodologies and definitions, transdisciplinary expertise, and longitudinal design are required to better understand the complex role of feeding on sleep.

Temperament and sleep behaviors in infants and toddlers living in low-income homes

Temperament is a dynamic trait that can be shaped by maturity and environmental experiences. In this study, we sought to determine whether and the extent to which temperament was predicted by sleeping behaviors in an understudied sample of primarily Black and White infants and toddlers living in low-income homes (N = 150). Sleeping behaviors were assessed at 15-19 months of age with caregiver report of the Tayside Children's Sleep Questionnaire. Temperament was examined as effortful control, negativity, and surgency with the Infant Behavior Questionnaire Very Short Form at 9-12 months of age and with the Early Childhood Behavior Questionnaire Short Form at 20-24 months of age. Covariates were maternal education, household income, and child sex and race. Continuous variables were standardized, then missing data from independent variables were multiply imputed in 20 datasets. Regression analyses showed that about 1 SD improvement in toddler sleep behaviors significantly predicted about 1/5 SD better toddler effortful control. However, sleep behaviors did not significantly predict toddler surgency or negative affect. This study shows that for a sample of infants and toddlers in low-income homes, how a child learns to regulate sleeping behaviors may influence the development of overall effortful control about six months later.

Sleep during infancy, inhibitory control and working memory in toddlers: findings from the FinnBrain cohort study

Background

Sleep difficulties are associated with impaired executive functions (EFs) in school-aged children. However, much less is known about how sleep during infancy relates to EF in infants and toddlers. The aim of this study was to investigate whether parent-reported sleep patterns at 6 and 12 months were associated with their inhibitory control (IC) and working memory (WM) performances at 30 months.

Methods

This study included children whose parents filled in a sleep questionnaire at 6 or 12 months and who participated in the development assessment at 30 months (initial available sample at 30 months; N = 472). The final sample comprised (a) 359 infants with IC task and sleep questionnaire at 6 months and 322 toddlers at 12 months and (b) 364 infants with WM task and sleep questionnaire at 6 months and 327 toddlers at 12 months. Nighttime, daytime and total sleep duration, frequency of night awakenings, time awake at night, and proportion of daytime sleep were assessed at 6 and 12 months using the Brief Infant Sleep Questionnaire. IC at 30 months was measured using a modified version of the Snack Delay task, and WM was measured at 30 months using the Spin the Pots task. Further, children were divided into three groups (i.e., “poor sleepers”, “intermediate sleepers”, and “good sleepers”) based on percentile cut-offs (i.e., <10th, 10th–90th and > 90th percentiles) to obtain a comprehensive understanding of the direction and nature of the associations between sleep and EF in early childhood.

Results

Our results showed an inverted U-shaped association between proportion of daytime sleep at 12 months and IC at 30 months, indicating that average proportions of daytime sleep were longitudinally associated with better IC performance. Furthermore, a linear relation between time awake at night at 12 months and WM at 30 months was found, with more time awake at night associating with worse WM.

Conclusions

Our findings support the hypothesis that sleep disruption in early childhood is associated with the development of later EF and suggest that various sleep difficulties at 12 months distinctively affect WM and IC in toddlers, possibly in a nonlinear manner.

The role of prior sleep for divergent thinking in infants

Higher-order cognitive functions seem particularly vulnerable to disruptions in prior sleep in school-aged children and adult populations. This study tested whether divergent thinking in infants varied as a function of prior sleep. Forty-three infants aged 13-16 months participated in a behavioural assessment of divergent thinking. Length of wakefulness since last sleep was experimentally manipulated. In addition, potential relations between divergent thinking and sleep quantity and quality during the night immediately before the assessment, as well as during three consecutive nights preceding the assessment, were examined using actigraphy recordings in combination with parent diaries. Divergent thinking was not impaired by lack of sleep within the previous 4 h. Divergent thinking was consistently related to night-time sleep quality and quantity prior to the assessment. These results suggest that timing of prior naturally occurring daytime sleep is less relevant for emergent divergent thinking capacity than quality and quantity of preceding night-time sleep.

Sleep and self-control: A systematic review and meta-analysis

Controlling impulses and overcoming temptations (i.e., self-control) are key aspects of living a productive life. There is a growing yet disperse literature indicating that sleep is an important predictor of self-control. The goal of this meta-analysis is to empirically integrate the findings from multiple literatures, and investigate whether sleep quality, and sleep duration predict self-control. To provide a thorough understanding of the proposed relationships, this meta-analysis also investigated potential differences between the level of analysis (between-individual vs. within-individual), research design (experiment vs. correlation; and cross-sectional vs. time-lagged), and types of measure (subjective vs. objective for sleep and self-control). A systematic review was conducted through ABI/Inform (including PsycInfo), ERIC, ProQuest Dissertation & Theses, PubMed, and Psychology Database using keywords related to self-control and sleep. Sixty-one independent studies met the inclusion criteria. The results, in general, suggest that sleep quality (between-individual 0.26, CI 0.21; 0.31; and within-individual 0.35, CI 0.24; 0.45), and sleep duration (between-individual 0.14, CI 0.07; 0.21; and within-individual 0.20, CI 0.09; 0.31) are all related to self-control. Given the impact of self-control on how individuals live productive lives, a future research agenda should include a deeper investigation in the causal process (potentially via prefrontal cortex activity) linking sleep and self-control, and an examination of the moderators (individual and contextual variables) that could impact the relationship between sleep and self-control.

'Investigating longitudinal associations between parent reported sleep in early childhood and teacher reported executive functioning in school-aged children with autism'

Up to 80% of children with autism spectrum disorder (ASD) experience sleep disturbance. Poor sleep impairs executive functioning (EF), a lifelong difficulty in ASD. Evidence suggests EF difficulties in ASD are exacerbated by poor sleep. We examine whether early childhood sleep disturbances are associated with worsening EF trajectories in school-aged children with ASD. A subsample (n=217) from the Pathways in ASD longitudinal study was analyzed. The Children's Sleep Habits Questionnaire captured sleep duration, onset, and night awakenings before age 5 (Mean=3.5years). Metacognition (MI) and Behavioral Regulation (BRI) indices, on the Teacher Behavior Rating Inventory of Executive Functioning, were used to measure cognitive and affective components of EF respectively at four time-points (7.8-11.8years). We applied latent growth curve models to examine associations between sleep and EF, accounting for relevant covariates, including school-age sleep (Mean=6.7years). Sleep traits had different age-related impacts on behavioral regulation, but not metacognition. Longer sleep onset at 3.5 years was associated with a worsening BRI difficulties slope (b=2.07, p<0.04), but conversely associated with lower BRI difficulties at 7.7 years (b=-4.14, p=0.04). A longer sleep onset at 6.7 years was related to higher BRI difficulties at 7.7 years (b=7.78, p<0.01). Longer sleep duration at 6.7 years was associated with higher BRI difficulties at age 7.7 (b=3.15, p=0.01), but subscale analyses revealed shorter sleep duration at age 6.7 was linked to a worsening inhibition slope (b=-0.60, p=0.01). Sleep onset is a robust early correlate of behavior regulation in children with ASD, whereas sleep duration is a later childhood correlate.

Researcher Choices for Infant Sleep Assessment: Parent Report, Actigraphy, and a Novel Video System

Incorporating infant sleep, either as a predictor or as an outcome variable, into interdisciplinary work has become increasingly popular. Sleep researchers face many methodological choices that have implications for the reliability and validity of the data. Here, the authors directly investigated the impact of design and measurement choices in a small, longitudinal sample of infants. Three sleep measurement techniques-parent-reported sleep diaries, actigraphy (Micromini Sleep Watch), and a commercial videosomnography (Nanit)-were included, using actigraphy as the baseline. Nine infants' sleep (4 girls) was measured longitudinally using all three measurement techniques. Nanit provided summary statistics, using a proprietary algorithm, for nightly sleep parameters. The actigraphy data were analyzed with both the Sadeh Infant and Sadeh algorithms. The extent to which measurements converged on sleep start and end time, number of wake episodes, sleep efficiency, and sleep duration was assessed. Measures were positively correlated. Difference scores revealed similar patterns of greater sleep estimation in parent reports and Nanit compared with actigraphy. Bland-Altman plots revealed that much of the data were within the limits of agreement, tentatively suggesting that Nanit and actigraphy may be used interchangeably. Graphs display significant variability within and between individual infants as well as across measurement techniques. Potential confounding variables that may explain the discrepancies between parent report, Sadeh Infant, Sadeh, and Nanit are discussed. The findings are also used to speak to the advantages and disadvantages of design and measurement choices. Future directions focus on the unique contributions of each measurement technique and how to capitalize on them.

Associations between sleep duration, adiposity indicators, and cognitive development in young children

OBJECTIVE

This study aimed to examine the associations between sleep duration, adiposity indicators, and cognitive development in young children.

METHODS

Participants were 217 children aged 19-60 months in Canada in the supporting Healthy physical AcTive Childcare setting (HATCH) study. Nap duration and nighttime sleep duration were assessed using a parent questionnaire and were summed up as total sleep duration. Body mass index (BMI) z-scores and weight status were determined using the World Health Organization growth standards. Expressive vocabulary and working memory were assessed using the Early Years Toolbox in preschoolers only (36-60 months; n = 101). Mixed models (BMI z-score, expressive vocabulary) and generalized mixed models (weight status, working memory) were conducted.

RESULTS

A linear association between total sleep duration and BMI z-score (B = -0.12; 95% CI: -0.23, -0.01) were observed. Compared to children having nighttime sleep within ±1SD (9.13-11.13 h/d) of the mean, those having shorter nighttime sleep had higher BMI z-scores (B = 0.39; 95% CI: 0.06, 0.73) and an increased risk of being overweight (OR = 4.54; 95% CI: 1.39, 14.81). Nap duration was not associated with adiposity indicators. In preschoolers, sleep duration was not associated with expressive vocabulary. Total sleep duration and nap duration were not associated with working memory. However, non-nappers were more likely to have greater working memory (OR = 4.04; 95% CI: 1.09, 14.92) compared to those having nap duration within ±1SD (0.46-2.18 h/d) of the mean.

CONCLUSION

Promoting longer total sleep, including more than nine hours of nighttime sleep, appears important for maintaining healthy adiposity levels in young children. Cessation of napping may be associated with better working memory in preschoolers.

Neonatal sleep development and early learning in infants with prenatal opioid exposure

The aim of this chapter is to examine the role of sleep and cognition in the context of the cumulative risk model examining samples of at-risk infants and maternal-infant dyads. The cumulative risk model posits that non-optimal developmental outcomes are the result of multiple factors in a child's life including, but not limited to, prenatal teratogenic exposures, premature birth, family socioeconomic status, parenting style and cognitions as well as the focus of this volume, sleep. We highlight poor neonatal sleep as both an outcome of perinatal risk as well as a risk factor to developing attentional and cognitive capabilities during early childhood. Outcomes associated with and contributing to poor sleep and cognition during infancy are examined in relation to other known risks in our clinical population. Implications of this research and recommendations for interventions for this population are provided.

Individual differences in the effects of child sleep problems on early executive functioning

Sleep is a critical health behavior with important implications for child development. This chapter discusses the effects of sleep problems on early child executive functioning (EF), with an emphasis on individual differences that might moderate this relationship. Specifically, we (1) provide a brief background on sleep and EF in early childhood; (2) review literature on the association between sleep and EF; (3) review literature on individual differences in the effects of sleep problems on EF; (4) offer recommendations for future research on moderators of the sleep-EF association, and (5) briefly describe an ongoing study examining the moderators of the sleep-EF association within a longitudinal study from pregnancy to preschool.

The relation between sleep and neurocognitive development in infancy and early childhood: A neuroscience perspective

Sleep is essential for human life. It has different characteristics in the early stages of life compared to later periods: during development, qualitative and quantitative changes in sleep features occur such as the onset of REM/NREM sleep at 3 months, the progressive increase of night sleep duration, and the reduction of total sleep time. Sleep seems to be essential in the cognitive functions' development, especially in the first period of life. Indeed, higher rates of night sleep at the age of 12 and 18 months are associated with higher executive functions' performance. Furthermore, memory consolidation occurs during sleep and sleep contributes to children's learning not only in retaining information but also in organizing memories most efficiently. Therefore, sleep problems could cause negative effects on some features of cognitive development like memory, executive functions, and learning process. There is also an intimate relationship between sleep and regulation of emotional brain functions, with a link between sleep disturbance and behavioral problems.

Sleep and self-regulation in early childhood

What is the role of sleep in children's behavioral, emotional, and cognitive regulation? This chapter considers theoretical and conceptual links between sleep and self-regulation, with special attention to sleep and self-regulation in early childhood. We selectively review the growing body of research on associations between sleep and self-regulation, mentioning some methodological issues. We also consider how child characteristics and sociocontextual factors may interact with sleep in the development of self-regulation in early childhood. We provide some relevant empirical examples from our own research.