A review of the effects of sleep during the first year of life on cognitive, psychomotor, and temperament development

Maturation of infant sleep during the first 6 months of life: a mini-scoping review

Introduction

Several foundational aspects of neurodevelopment occur during the early months of infant life, most notably the maturation and consolidation of wake/sleep cycles. Past studies have had difficulty quantifying infant sleep, with most researchers relying on low-resolution caregiver surveys. Data obtained from nightly measurements have not yet been aggregated across studies to clarify developmental trajectories and population norms. This mini-scoping review assesses data collected from actigraphy and sleep diaries; the two most common nightly infant sleep measurement techniques.

Methods

The PubMed database was used to identify studies from 2000 to 2024 utilizing actigraphy and/or sleep diaries, and which report total night sleep (TNS), longest sleep stretch (LSS), and/or frequency of night wakings (NW) during the first 6 months of life. Data was then compiled per metric to reveal the extent of inter-and intra-study variability, and curves were fit to highlight developmental trajectories.

Results

A total of 35 articles met inclusion criteria (16 studies using actigraphy only, 8 studies using sleep diary only, and 11 studies using both actigraphy and sleep diaries). The sample sizes of these studies ranged from 13 to 320 infants. The majority of studies (N = 28) reported two or fewer age data points.

Conclusion

Aggregation and regression revealed longitudinal trends, but highlighted variability within and between studies, as well as systematic differences between measurement methods. In order to establish reliable benchmarks, future studies must include well defined, objective measures of sleep as well as greater methodological consistency, larger cohorts, more frequent sampling, and clear disclosure of methodological limitations.

A Closer Look at Paediatric Sleep: Sleep Health and Sleep Behavioural Disorders in Children and Adolescents

Adequate sleep is crucial for healthy development, contributing significantly to physical and mental well-being. While research on paediatric sleep is expanding, there remain several open questions. This narrative review provides an overview of our current knowledge on paediatric sleep health and identifies literature gaps, considering factors such as age, gender, cultural differences, and the interplay between sleep, physical activity, nutrition, and mental health. It also considers sleep health in the more specific group of children with neurodevelopmental disorders. By viewing paediatric sleep health as a multidimensional construct, this review discusses age-specific issues, including the different factors affecting satisfaction, daytime alertness, sleep timing, efficiency and duration, and sleep-related behaviours. While gender differences in sleep health become apparent after puberty, few studies have addressed sex differences in children or different parental attitudes toward sleep in boys and girls. Cultural differences in sleep duration, timing, and setting are reported from infancy through adolescence; however, the cultural influence on sleep health, particularly during adolescence, remains unclear. This is crucial when considering the effects of screen time, smartphone use, and social media exposure on sleep. Further research is required to understand how sleep, nutrition, and physical health interact throughout the developmental span. Additionally, this review underscores the protective nature of sleep for adolescent mental health and for the management of emotional and behavioural problems in children with neurodevelopmental disorders. The review identifies critical areas for future research to enhance our understanding of paediatric sleep health and develop more effective and tailored interventions and preventive programmes.

Behavioural pharmacology predicts disrupted signalling pathways and candidate therapeutics from zebrafish mutants of Alzheimer's disease risk genes

By exposing genes associated with disease, genomic studies provide hundreds of starting points that should lead to druggable processes. However, our ability to systematically translate these genomic findings into biological pathways remains limited. Here, we combine rapid loss-of-function mutagenesis of Alzheimer's risk genes and behavioural pharmacology in zebrafish to predict disrupted processes and candidate therapeutics. FramebyFrame, our expanded package for the analysis of larval behaviours, revealed that decreased night-time sleep was common to F0 knockouts of all four late-onset Alzheimer's risk genes tested. We developed an online tool, ZOLTAR, which compares any behavioural fingerprint to a library of fingerprints from larvae treated with 3677 compounds. ZOLTAR successfully predicted that sorl1 mutants have disrupted serotonin signalling and identified betamethasone as a drug which normalises the excessive day-time sleep of presenilin-2 knockout larvae with minimal side effects. Predictive behavioural pharmacology offers a general framework to rapidly link disease-associated genes to druggable pathways.

Association between infant sleep and neurodevelopment in a prospective birth cohort study

OBJECTIVES

To investigate the association of infant sleep and sleep trajectories through the first year of life with infant neurodevelopment.

METHODS

This study was conducted with 3251 infants in China. Sleep parameters were evaluated by the Brief Infant Sleep Questionnaire at 42days, 6months, and 1year of age. Neurodevelopment was evaluated at 1year of age using the Bayley Scales of Infant and Toddler Development, Third Edition. The latent variable growth curve model was used to evaluate the developmental trajectories of infant sleep, including total sleep duration trajectories, night awakening trajectories and sleep onset latency trajectories. Poisson regression was applied to assess the association between sleep parameters and sleep trajectories and infant neurodevelopment.

RESULTS

Infants with frequent night awakenings at 6months had a higher risk of nonoptimal gross motor development. Additionally, infants with prolonged sleep onset latency at 1year had an increased risk of nonoptimal fine and gross motor development. A consistent frequent night-awakening trajectory increased the risk of nonoptimal gross motor development (adjusted relative risk, 1.52; 95% confidence interval, 1.09 to 2.10). Furthermore, an increasing trajectory in sleep onset latency was associated with an increased risk of nonoptimal fine (adjusted relative risk, 2.70; 95% confidence interval, 1.12 to 6.51) and gross motor development (adjusted relative risk, 2.76; 95% confidence interval, 1.70 to 4.48). However, no significant association was observed between total sleep duration, or its trajectory, and infant neurodevelopment.

CONCLUSIONS

Sleep problems or specific sleep trajectories during the initial year of life may increase risk of compromised neurodevelopment.

Exploring Developmental Connections: Sleep Patterns, Self-Locomotion, and Vocabulary Growth in Early Childhood

Current research indicates likely developmental connections between the evolution of sleep patterns, motor skills progression, and the expansion of vocabulary. These connections are grounded in the well-established role of sleep in memory and learning, as well as in the cascading effects on language development of the acquisition of new motor skills. However, no study has so far undertaken a comprehensive and systematic examination of these connections or explored their developmental trajectory over time. Yet understanding vocabulary development depends on considering development in the sleep regulation and motor domains, to provide a biologically grounded explanation of how early lexicons are built and strengthened. This study investigates the links between vocabulary growth and two significant changes occurring over the first 2 years of life: self-initiated locomotion and the consolidation of overnight sleep. Our results reveal mutual associations between these domains, which tend to emerge during periods of marked developmental change in language, motor skills, and sleep patterns regulation. Moreover, these associations were observed to change over time, suggesting dynamic interconnections between these developmental domains. Our findings point toward the importance of investigating vocabulary development from a dynamic systems perspective, as the product of continuous interactions between cognition, the body and the environment.

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, and SCOPUS). Of 7136 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, 2 found exclusively significant associations (SAs) between infant sleep and cognitive/psychomotor development, 2 found no SAs and 17 found mixed results (MRs). Studies with exclusively significant results used a single sleep variable and single timepoint designs. Studies finding MRs or no SAs used multiple sleep, developmental variables, or multi-timepoint designs. Eight out of 10 studies and 7 out of 8 studies investigating nocturnal and total sleep duration, respectively, found no SA with developmental outcomes. While 63% of studies were rated as having good methodological quality, all studies but one had an estimated power of less than 0.80.

CONCLUSIONS

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.

Impact of daily music on comfort scores in preterm infants: a randomized controlled trial

BACKGROUND

Premature birth heightens neurodevelopmental risks, theorized to partly stem from altered sensory inputs and disrupted sleep patterns. Modifying the acoustic milieu through music intervention (MI) offers promise to improve neonatal comfort, reduce sleep disturbances, and stabilize physiological parameters. This study explores the impact of non-pharmacological MI on these health indicators within the Neonatal Intensive Care Unit (NICU).

METHODS

A single-blinded RCT was conducted. Premature infants (34 > GA > 29 wks) were randomly assigned to either receive 8 min of daily MI or placebo for up to 15 days. Validated behavioral comfort scores were visually obtained by a blinded observer before and after intervention. Additionally, physiological signs (HR, RR, SatO2) were recorded. Differences between the groups were analyzed using χ² tests and t-tests.

RESULTS

In total 56 preterm infants were included. After intervention, comfort levels increased significantly in the MI compared to placebo group (p = 0.000). Neonates receiving MI transitioned from wakefulness to a state of sleep significantly more compared to placebo (p = 0.002). Physiological parameters remained stable.

CONCLUSIONS

This study adds to existing literature demonstrating that a music intervention in a NICU setting can enhance comfort and sleep of premature infants without adversely affecting physiological parameters.

IMPACT

The study demonstrates that music interventions (MI) in a Neonatal Intensive Care Unit (NICU) setting can significantly increase comfort levels and positively impact the sleep of premature infants without negatively impacting their physiological parameters. This research increases evidence for non-pharmacological interventions, specifically music, as beneficial for the well-being of premature infants in NICU settings. It replicates and expands upon previous methodological designs, providing more robust evidence of MI's positive effects on this vulnerable population. The positive outcomes of music intervention could influence hospital policies by integrating non-pharmacological practices into standard neonatal care protocols to enhance developmental support for premature infants.

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.

Energetic demands regulate sleep-wake rhythm circuit development

Sleep and feeding patterns lack strong daily rhythms during early life. As diurnal animals mature, feeding is consolidated to the day and sleep to the night. In Drosophila, circadian sleep patterns are initiated with formation of a circuit connecting the central clock to arousal output neurons; emergence of circadian sleep also enables long-term memory (LTM). However, the cues that trigger the development of this clock-arousal circuit are unknown. Here, we identify a role for nutritional status in driving sleep-wake rhythm development in Drosophila larvae. We find that in the 2nd instar larval period (L2), sleep and feeding are spread across the day; these behaviors become organized into daily patterns by the 3rd instar larval stage (L3). Forcing mature (L3) animals to adopt immature (L2) feeding strategies disrupts sleep-wake rhythms and the ability to exhibit LTM. In addition, the development of the clock (DN1a)-arousal (Dh44) circuit itself is influenced by the larval nutritional environment. Finally, we demonstrate that larval arousal Dh44 neurons act through glucose metabolic genes to drive onset of daily sleep-wake rhythms. Together, our data suggest that changes to energetic demands in developing organisms trigger the formation of sleep-circadian circuits and behaviors.

Sleep disturbances are associated with greater healthcare utilization in children with autism spectrum disorder

BACKGROUND

Sleep disturbances are frequently reported in children with autism spectrum disorder (ASD) and are associated with the severity of co-occurring symptoms. This study's aim was to examine the extent of healthcare utilization and clinical outcomes associated with sleep disturbances in children with ASD.

STUDY DESIGN

A retrospective, cross-sectional study of 541 children with ASD from the Azrieli National Center for Autism and Neurodevelopment Research (ANCAN) whose parents completed the Children's Sleep Habits Questionnaire (CSHQ). Children with a total CSHQ score ≥ 48 were defined as having sleep disturbances. Sociodemographic characteristics, ASD diagnostic measures, chronic co-occurring conditions, medication usage, hospitalizations, visits to the emergency room (ER), and visits to specialists were compared in ASD children with and without sleep disturbances. Multivariate logistic regression models were then used to assess the independent association of sleep disturbances with clinical characteristics and healthcare utilization.

RESULTS

Of the 541 children with ASD, 257 (47.5%) had sleep disturbances. Children with sleep disturbances exhibited higher rates of multiple (≥ 3) co-occurring conditions (19.1% vs. 12.7%; p = 0.0414) and prescribed medications (45.5% vs. 32.7%; p = 0.0031) than other children. Finally, ASD children with sleep disturbances were 1.72 and 2.71 times more likely to visit the ER and be hospitalized than their counterparts (aOR = 1.72; 99%CI = 1.01-2.95; and aOR = 2.71; 99%CI = 1.10-6.67, respectively).

CONCLUSIONS

Our findings suggest that sleep disturbances are associated with greater healthcare utilization among children with ASD. Further studies could examine whether treating sleep disturbances in children with ASD yields additional clinical benefits beyond improvements in sleep.

Energetic Demands Regulate Sleep-Wake Rhythm Circuit Development

Sleep and feeding patterns lack strong daily rhythms during early life. As diurnal animals mature, feeding is consolidated to the day and sleep to the night. In Drosophila, circadian sleep patterns are initiated with formation of a circuit connecting the central clock to arousal output neurons; emergence of circadian sleep also enables long-term memory (LTM). However, the cues that trigger the development of this clock-arousal circuit are unknown. Here, we identify a role for nutritional status in driving sleep-wake rhythm development in Drosophila larvae. We find that in the 2nd instar larval period (L2), sleep and feeding are spread across the day; these behaviors become organized into daily patterns by the 3rd instar larval stage (L3). Forcing mature (L3) animals to adopt immature (L2) feeding strategies disrupts sleep-wake rhythms and the ability to exhibit LTM. In addition, the development of the clock (DN1a)-arousal (Dh44) circuit itself is influenced by the larval nutritional environment. Finally, we demonstrate that larval arousal Dh44 neurons act through glucose metabolic genes to drive onset of daily sleep-wake rhythms. Together, our data suggest that changes to energetic demands in developing organisms trigger the formation of sleep-circadian circuits and behaviors.

Sleep duration trajectories and cognition in early childhood: A systematic review

Sleep is dynamic in childhood and studies have shown the relationship between sleep and cognition in children. As the human brain is the most plastic during childhood, the study of longitudinal sleep patterns and neurocognition is an important research area. We aimed to systematically review studies that investigated sleep duration trajectories and cognition in typically-developing children. We searched four databases for articles published between 2003 to October 2023. We included observation studies of children with sleep duration trajectories as a predictor and outcomes related to cognition, memory, language, developmental milestones, intelligence or executive function. We excluded studies where children had atypical development or completed the sleep and neurocognitive assessments after six and 12 years of age respectively. Out of 752 articles identified, 511 were screened and 23 full texts were assessed. The selected studies included three single trajectory and four multiple group trajectories studies. We found associations between both types of trajectories and cognitive development. Overall, children with longer sleep trajectories or more mature sleep pattern with rapid decrease in sleep duration, had better performance scores in developmental assessment tools, and intelligence tests. Findings for language and executive functioning were mixed, whereby some studies found associations and others did not.

Sleep disturbances and behavioral symptoms in pediatric Sotos syndrome

Background

Sotos syndrome (SoS) is a rare overgrowth genetic disease caused by intragenic mutations or microdeletions of the NSD1 gene located on chromosome 5q35. SoS population might present cognitive impairment and a spectrum of behavioral characteristics, with a worse profile in patients with microdeletion. Although patients with SoS are known to have impaired sleep habits, very little data are available. The present study aimed to assess the prevalence of sleep disorders (SDs) in a pediatric cohort of patients with SoS and their correlation with neuropsychiatric profiles.

Methods

We included patients with a SoS diagnosis and age < 18 years; all patients underwent a comprehensive neuropsychological assessment, including evaluation of cognition, adaptive functions through the Adaptive Behavior Assessment System-Second Edition (ABAS-II), and behavioral problems using the Achenbach Child Behavior Checklist (CBCL) and Conners' Parent Rating Scale-Revised (CPRS-R:L) questionnaire. To investigate the presence of SD parents, the Sleep Disturbance Scale for Children (SDSC) was completed.

Results

Thirty-eight patients (M 61%, F 39%, mean age 11.1 ± 4.65 years) were included in the study. Although only two had a prior SD diagnosis, 71.1% (N = 27) exhibited pathological scores on SDSC. No statistically significant associations were found between positive SDSC results and genetic microdeletion, intellectual disability (ID), or other medical conditions/treatments. However, a positive correlation emerged between SDSC scores and Conners' Global Index (p = 0.048) and Restless/Impulsive (p = 0.01) scores, CBCL externalizing (p = 0.02), internalizing (p = 0.01), and total scores (p = 0.05). Conversely, a negative linear relationship was observed between the SDSC score and the ABAS GAC and ABAS CAD scores (p = 0.025).

Conclusion

We detected an SD in 71.1% of our sample, with a positive relation between SD and internalizing and externalizing symptom levels, especially hyperactivity and impulsivity. Our study demonstrated a high prevalence of SD in pediatric patients with SoS, highlighting that all patients should be screened for this problem, which has a great impact on the quality of life of patients and their families.

The past, current, and future of neonatal intensive care units with artificial intelligence: a systematic review

Machine learning and deep learning are two subsets of artificial intelligence that involve teaching computers to learn and make decisions from any sort of data. Most recent developments in artificial intelligence are coming from deep learning, which has proven revolutionary in almost all fields, from computer vision to health sciences. The effects of deep learning in medicine have changed the conventional ways of clinical application significantly. Although some sub-fields of medicine, such as pediatrics, have been relatively slow in receiving the critical benefits of deep learning, related research in pediatrics has started to accumulate to a significant level, too. Hence, in this paper, we review recently developed machine learning and deep learning-based solutions for neonatology applications. We systematically evaluate the roles of both classical machine learning and deep learning in neonatology applications, define the methodologies, including algorithmic developments, and describe the remaining challenges in the assessment of neonatal diseases by using PRISMA 2020 guidelines. To date, the primary areas of focus in neonatology regarding AI applications have included survival analysis, neuroimaging, analysis of vital parameters and biosignals, and retinopathy of prematurity diagnosis. We have categorically summarized 106 research articles from 1996 to 2022 and discussed their pros and cons, respectively. In this systematic review, we aimed to further enhance the comprehensiveness of the study. We also discuss possible directions for new AI models and the future of neonatology with the rising power of AI, suggesting roadmaps for the integration of AI into neonatal intensive care units.

Longitudinal sleep multi-trajectories from age 1 to 5.5 years and their early correlates: results from the Étude Longitudinale Française depuis l'Enfance birth cohort study

STUDY OBJECTIVES

To identify sleep multi-trajectories in children from age 1 to 5.5 years and their early correlates.

METHODS

We collected early family, maternal, and child characteristics, including children's nighttime sleep duration (NSD) and daytime sleep duration (DSD), night waking (NW), and sleep-onset difficulties (SOD), by parental phone interviews at age 2 months and 1-, 2-, 3.5-, and 5.5 years. Group-based multi-trajectory modeling identified sleep multi-trajectory groups. Multinomial logistic regression assessed associations with early factors.

RESULTS

We identified five distinct sleep multi-trajectory groups for NSD, DSD, NW, and SOD in 9273 included children. The "Good sleepers" (31.6%) and "Long sleepers" (31.0%) groups had low NW and SOD prevalence and shorter NSD but longer DSD in "Good sleepers" than in "Long sleepers." The "Good sleepers but few SOD" group (10.3%) had long NSD and DSD but a SOD peak at age 3.5 years; the "Improving NW and SOD" group (9.6%) showed short but rapidly increasing NSD to a plateau and high but decreasing NW and SOD; the "Persistent NW and SOD" group (17.5%) had persistent high NW and SOD. Maternal depression during pregnancy and sleep habits at age 1 (e.g. parental presence or feeding to fall asleep, sleeping at least part of the night away from own bed) were common risk factors associated with the most disordered sleep multi-trajectory groups.

CONCLUSIONS

We identified distinct sleep multi-trajectory groups and early life-associated factors in preschoolers. Most of the factors associated with the most sleep-disordered multi-trajectory groups are likely modifiable and provide clues for early prevention interventions.

Lack of association between behavioral development and simplified topographical markers of the sleep EEG in infancy

The sleep EEG mirrors neuronal connectivity, especially during development when the brain undergoes substantial rewiring. As children grow, the slow-wave activity (SWA; 0.75-4.25 Hz) spatial distribution in their sleep EEG changes along a posterior-to-anterior gradient. Topographical SWA markers have been linked to critical neurobehavioral functions, such as motor skills, in school-aged children. However, the relationship between topographical markers in infancy and later behavioral outcomes is still unclear. This study aims to explore reliable indicators of neurodevelopment in infants by analyzing their sleep EEG patterns. Thirty-one 6-month-old infants (15 female) underwent high-density EEG recordings during nighttime sleep. We defined markers based on the topographical distribution of SWA and theta activity, including central/occipital and frontal/occipital ratios and an index derived from local EEG power variability. Linear models were applied to test whether markers relate to concurrent, later, or retrospective behavioral scores, assessed by the parent-reported Ages & Stages Questionnaire at ages 3, 6, 12, and 24 months. Results indicate that the topographical markers of the sleep EEG power in infants were not significantly linked to behavioral development at any age. Further research, such as longitudinal sleep EEG in newborns, is needed to better understand the relationship between these markers and behavioral development and assess their predictive value for individual differences.

Contextual considerations in infant sleep: Offering alternative interventions to families

Infant sleep problems are one of the commonly reported reasons parents seek professional help, yet what constitutes a "sleep problem" depends on the models used to explain the development of infant sleep. The current models are based on research conducted in the western context where infant solitary sleeping is the norm. Parent-child co-sleeping is the norm in many cultures around the world. We argue that the primary focus of current research on parent-child interactions as the mediating context for the development of infant sleep problems has inherently made these models and ensuing interventions less sensitive and applicable to infant sleep problems in the context of co-sleeping families. When families present for help with infant sleep difficulties, extinction based behavioral interventions or interventions focused on reducing parental presence at bedtime are commonly recommended. These recommendations may not always align with cultural values and parenting practices of all families, therefore precluding these families from getting necessary help. In attempting to provide families with choices that depart from behavioral based interventions, this paper draws on research and adapts current models to propose an alternative to conceptualize perceptions of infant sleep problems that may be sensitive to and applied across various cultural and personal contexts. We attempt to provide a rationale for interventions that are inclusive and sensitive to families where reduced parental nighttime responsiveness may not be a preferred choice.

Racial and ethnic disparities in insufficient sleep among US in infants and preschoolers

OBJECTIVE

To examine racial and ethnic disparities and associated factors of insufficient sleep among children from infancy to preschool-aged.

METHODS

We analyzed parent-reported data on US children ages 4 months-5 years (n = 13,975) from the 2018 and 2019 National Survey of Children's Health. Children who slept less than the age-specific minimum hours recommended by the American Academy of Sleep Medicine were classified as having insufficient sleep. Logistic regression was used to estimate unadjusted and adjusted odds ratios (AOR).

RESULTS

An estimated 34.3% of children from infancy to preschool-aged experienced insufficient sleep. Socioeconomic factors (poverty [AOR] = 1.5, parents' education level [AORs] from 1.3 to 1.5); parent-child interaction variables (AORs from 1.4 to 1.6); breast feeding status (AOR = 1.5); family structure (AORs from 1.5 to 4.4); and weeknight bedtime regularity (AORs from 1.3 to 3.0) were significantly associated with having insufficient sleep. Non-Hispanic Black (OR = 3.2) and Hispanic children (OR = 1.6) had significantly higher odds of insufficient sleep compared to non-Hispanic White children. Racial and ethnic disparities in insufficient sleep between non-Hispanic White children and Hispanic children were largely attenuated by adjusting for social economic factors. However, the difference in insufficient sleep between non-Hispanic Black and non-Hispanic White children remains (AOR = 1.6) after adjusting socioeconomic and other factors.

CONCLUSIONS

More than one-third of the sample reported insufficient sleep. After adjusting for socio-demographic variables, racial disparities in insufficient sleep decreased but persistent disparities existed. Further research is warranted to examine other factors and develop interventions to address multilevel factors and improve sleep health among racial and ethnic minority group children.

The association between vitamin D status and sleep duration in school-aged children; the CASPIAN-V study

Background

Considering the high prevalence of both vitamin D deficiency (VDD) and sleep impairment in children and adolescents, this study was conducted to determine the association between VDD and sleep duration in the Iranian pediatric population.

Methods

This multicentric national study was conducted in 2019 on 2564 frozen sera obtained from 7 to 18- year students who were studied in the fifth survey of a national school-based surveillance program conducted in 30 provinces of Iran. Sleep duration was assessed using a questionnaire based on the World Health Organization-Global School-based Student Health Survey protocol. Short sleep duration was defined as sleep duration less than 8 h/day VDD Vitamin D < 20 ng/dL, and vitamin D insufficiency as 20-30 ng/dL.An adjusted logistic regression model was applied to evaluate the associations of vitamin D status with sleep duration.

Results

The Mean (SD) of students' age was 12.1(3.0) years; overall 10.6%of participants had VDD and 23% of participants had short sleep duration. in the adjusted logistic model, students with a low level of vitamin D (insufficient and deficient) had a higher odds of short sleep duration in comparison to those with normal vitamin D level (OR: 1.29, 95%CI: 1.02-1.62).

Conclusion

The current study showed that low Vitamin D levels (insufficient and deficient)were significantly associated with short sleep duration in school-aged children. Further studies are recommended to determine the efficacy of vitamin D replacement in improving sleep duration and quality.

Sex differences in resting state functional connectivity across the first two years of life

Sex differences in behavior have been reported from infancy through adulthood, but little is known about sex effects on functional circuitry in early infancy. Moreover, the relationship between early sex effects on the functional architecture of the brain and later behavioral performance remains to be elucidated. In this study, we used resting-state fMRI and a novel heatmap analysis to examine sex differences in functional connectivity with cross-sectional and longitudinal mixed models in a large cohort of infants (n = 319 neonates, 1-, and 2-year-olds). An adult dataset (n = 92) was also included for comparison. We investigated the relationship between sex differences in functional circuitry and later measures of language (collected in 1- and 2-year-olds) as well as indices of anxiety, executive function, and intelligence (collected in 4-year-olds). Brain areas showing the most significant sex differences were age-specific across infancy, with two temporal regions demonstrating consistent differences. Measures of functional connectivity showing sex differences in infancy were significantly associated with subsequent behavioral scores of language, executive function, and intelligence. Our findings provide insights into the effects of sex on dynamic neurodevelopmental trajectories during infancy and lay an important foundation for understanding the mechanisms underlying sex differences in health and disease.

Development and Psychometric Properties of the Sleep Parenting Scale for Infants

Although infants' sleep behaviors are shaped by their interactions with parents at bedtime, few tools exist to capture parents' sleep parenting practices. This study developed a Sleep Parenting Scale for Infants (SPS-I) and aimed to (1) explore and validate its factorial structure, (2) examine its measurement invariance across mothers and fathers, and (3) investigate its reliability and concurrent and convergent validity. SPS-I was developed via a combination of items modified from existing scales and the development of novel items. Participants included 188 mothers and 152 mother-father dyads resulting in 340 mothers and 152 fathers; about half were non-Hispanic white. Mothers and fathers completed a 14-item SPS-I for their 12-month-old infant. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to explore and validate SPS-I's underlying structure. Multigroup CFA was used to examine measurement invariance across mothers and fathers. Reliability was examined using Cronbach's alpha. Concurrent validity was assessed using linear regressions examining associations between SPS-I factors and parent-reported infants nighttime sleep duration. Convergent validity was assessed using paired-sample t-tests to test whether the SPS-I subscale scores were similar between mothers and fathers in the same household. EFA and CFA confirmed a 3-factor, 12-item model: sleep routines, sleep autonomy, and screen media in the sleep environment. SPS-I was invariant across mothers and fathers and was reliable. Concurrent and convergent validity were established. SPS-I has good psychometric properties, supporting its use for characterizing sleep routines, sleep autonomy, and screen media in the sleep environment by mothers and fathers.Supplemental data for this article is available online at https://doi.org/10.1080/08964289.2021.2002799 .

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.

Sleep as a protective factor of children's executive functions: A study during COVID-19 confinement

Confinements due to the COVID-19 outbreak affected sleep and mental health of adults, adolescents and children. Already preschool children experienced acutely worsened sleep, yet the possible resulting effects on executive functions remain unexplored. Longitudinally, sleep quality predicts later behavioral-cognitive outcomes. Accordingly, we propose children's sleep behavior as essential for healthy cognitive development. By using the COVID-19 confinement as an observational-experimental intervention, we tested whether worsened children's sleep affects executive functions outcomes 6 months downstream. We hypothesized that acutely increased night awakenings and sleep latency relate to reduced later executive functions. With an online survey during the acute confinement phase we analyzed sleep behavior in 45 children (36-72 months). A first survey referred to the (retrospective) time before and (acute) situation during confinement, and a follow-up survey assessed executive functions 6 months later (6 months retrospectively). Indeed, acutely increased nighttime awakenings related to reduced inhibition at FOLLOW-UP. Associations were specific to the confinement-induced sleep-change and not the sleep behavior before confinement. These findings highlight that specifically acute changes of children's nighttime sleep during sensitive periods are associated with behavioral outcome consequences. This aligns with observations in animals that inducing poor sleep during developmental periods affects later brain function.

Prenatal alcohol exposure and child sleep problems: A family-based quasi-experimental study

Background

We examine whether associations between prenatal exposure to hazardous maternal alcohol consumption during the first trimester of pregnancy and sleep problems in young children represent a causal association.

Methods

The population-based sample consists of 15,911 mothers with 30,395 offspring from the Norwegian Mother, Father, and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN). Women self-reported pre-pregnancy alcohol consumption and consumption during the first trimester of pregnancy twice: at gestational weeks 17 and 30. Mothers reported their children's sleep problems, when they were 1.5 and 3 years (mean = 50; SD = 10). We tested models adjusting for (1) measured confounders, (2) unmeasured familial risk factors by sibling design, and (3) maternal hazardous drinking in the 3 months prior to pregnancy as an instrumental variable within the sibling design.

Results

Children of mothers with hazardous drinking during the first trimester were at increased risk of sleep problems at 1.5 (β = 1.14, 95%CI 0.04-2.25) and 3 (β = 2.86, 95%CI 1.85-3.87) years of age. These associations were reduced to close to zero and non-significant at 1.5 (β = -0.32, 95%CI -1.91-1.26) and 3 (β = 0.06, 95%CI -1.56-1.64) years when controlling for both familial and measured environmental risk factors.

Conclusions

There is a moderate association between maternal hazardous drinking during pregnancy and offspring sleep problems up to age three. This association is explained by risk factors differing between families and does not reflect a cause-effect relationship.

The role of nutrients in human neurodevelopment and their potential to prevent neurodevelopmental adversity

Nutritional deficits or excesses affect a huge proportion of pregnant women worldwide. Maternal nutrition has a significant influence on the fetal environment and can dramatically impact fetal brain development. This paper reviews current nutritional supplements that can be used to optimise fetal neurodevelopment and prevent neurodevelopmental morbidities, including folate, iodine, vitamin B12, iron, and vitamin D. Interestingly, while correcting nutritional deficits can prevent neurodevelopmental adversity, overcorrecting them can in some cases be detrimental, so care needs to be taken when recommending supplementation in pregnancy. The potential benefits of using nutrition to prevent neurodiversity is shown by promising nutraceuticals, sulforaphane and creatine, both currently under investigation. They have the potential to promote improved neurodevelopmental outcomes through mitigation of pathological processes, including hypoxia, inflammation, and oxidative stress. Neurodevelopment is a complex process and whilst the role of micronutrients and macronutrients on the developing fetal brain is not completely understood, this review highlights the key findings thus far.

Sleep State Trend (SST), a bedside measure of neonatal sleep state fluctuations based on single EEG channels

OBJECTIVE

To develop and validate an automated method for bedside monitoring of sleep state fluctuations in neonatal intensive care units.

METHODS

A deep learning-based algorithm was designed and trained using 53 EEG recordings from a long-term (a)EEG monitoring in 30 near-term neonates. The results were validated using an independent dataset from 30 polysomnography recordings. In addition, we constructed Sleep State Trend (SST), a bedside-ready means for visualizing classifier outputs.

RESULTS

The accuracy of quiet sleep detection in the training data was 90%, and the accuracy was comparable (85-86 %) in all bipolar derivations available from the 4-electrode recordings. The algorithm generalized well to a polysomnography dataset, showing 81% overall accuracy despite different signal derivations. SST allowed an intuitive, clear visualization of the classifier output.

CONCLUSIONS

Fluctuations in sleep states can be detected at high fidelity from a single EEG channel, and the results can be visualized as a transparent and intuitive trend in the bedside monitors.

SIGNIFICANCE

The Sleep State Trend (SST) may provide caregivers and clinical studies a real-time view of sleep state fluctuations and its cyclicity.

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 Sleep Well Baby project: an automated real-time sleep–wake state prediction algorithm in preterm infants

Study Objectives

Sleep is an important driver of early brain development. However, sleep is often disturbed in preterm infants admitted to the neonatal intensive care unit (NICU). We aimed to develop an automated algorithm based on routinely measured vital parameters to classify sleep–wake states of preterm infants in real-time at the bedside.

Methods

In this study, sleep–wake state observations were obtained in 1-minute epochs using a behavioral scale developed in-house while vital signs were recorded simultaneously. Three types of vital parameter data, namely, heart rate, respiratory rate, and oxygen saturation, were collected at a low-frequency sampling rate of 0.4 Hz. A supervised machine learning workflow was used to train a classifier to predict sleep–wake states. Independent training (n = 37) and validation datasets were validation n = 9) datasets were used. Finally, a setup was designed for real-time implementation at the bedside.

Results

The macro-averaged area-under-the-receiver-operator-characteristic (AUROC) of the automated sleep staging algorithm ranged between 0.69 and 0.82 for the training data, and 0.61 and 0.78 for the validation data. The algorithm provided the most accurate prediction for wake states (AUROC = 0.80). These findings were well validated on an independent sample (AUROC = 0.77).

Conclusions

With this study, to the best of our knowledge, a reliable, nonobtrusive, and real-time sleep staging algorithm was developed for the first time for preterm infants. Deploying this algorithm in the NICU environment may assist and adapt bedside clinical work based on infants’ sleep–wake states, potentially promoting the early brain development and well-being of preterm infants.

Association of fetal eye movement density with sleeping and developmental problems in 1.5-year-old infants

Eye movement density (EMD) is an evaluation index of rapid eye movements observed during sleep. This study aimed to investigate the association of fetal EMD with sleeping and developmental problems in infancy. We observed 60 normal singleton pregnancies (gestational age 28-37 weeks) using ultrasonography for 1 h. Fetal eye movements were counted, and EMD was calculated. Participants answered questionnaires regarding their child's sleep and development 1.5 years after their delivery. The outcomes of an infant's sleep were night awakening (yes or no), bedtime (before or after 22:00), and nighttime sleep duration (< 9 or ≥ 9 h). An infant's development was evaluated using the Child Behavior Checklist (CBCL) T-score. We found that decreased fetal EMD was associated with increased night awakening at the age of 1.5 years (odds ratio 0.84, 95% confidence interval 0.69-1.00 per unit decrease in EMD). However, fetal EMD was not associated with bedtime or nighttime sleep duration. In addition, fetal EMD was independently associated with the total problems T-score of the CBCL at the age of 1.5 years in the multivariate model (p = 0.047). In conclusion, fetal EMD may be associated with sleep and developmental problems in infants.

A scoping review of behavioral sleep stage classification methods for preterm infants

BACKGROUND

Sleep is paramount for optimal brain development in infants admitted to the neonatal intensive care unit. Besides (minimally) invasive technical approaches to study sleep in infants, there is currently a large variety of behavioral sleep stage classification methods (BSSCs) that can be used to identify sleep stages in preterm infants born <37 weeks gestational age. However, they operate different criteria to define sleep stages, which limits the comparability and reproducibility of research on preterm sleep. This scoping review aims to: 1) identify and elaborate on existing neonatal BSSCs used for preterm infants, 2) examine the reliability and validity of these BSSCs, and 3) identify which criteria are most used for different ages, ranging from 23 to 37 weeks postmenstrual age at observation.

METHODS

To map the existing BSSCs, PubMed, EMBASE and Cochrane were searched for studies using a BSSC to identify sleep stages in preterm infants.

RESULTS

In total, 36 BSSCs were identified with on average five item categories assessed per BSSC, most frequently: eyes, body movements, facial movements, sounds, and respiratory pattern. Furthermore, validity and reliability of the BSSCs were tested in less than half of the included studies. Finally, BSSCs were used in infants of all ages, regardless the age for which the BSSC was originally developed.

CONCLUSIONS

Items used for scoring in the different BSSCs were relatively consistent. The age ranges, reliability, and validity of the BSSCs were not consistently reported in most studies. Either validation studies of existing BSSCs or new BSSCs are necessary to improve the comparability and reproducibility of previous and future preterm behavioral sleep studies.

Actigraphy: Metrics reveal it is not a valid tool for determining sleep in neonates

Study of emerging sleep-wake patterns in neonates is important for promptly identifying and treating abnormal sleep behaviours to ensure healthy infant development and neurobehavioral outcomes. Current methods to assess sleep are costly, labour intensive, and particularly difficult to implement in fragile, hospitalised infants requiring intensive medical care. The aim of the present study was to assess the validity of actigraphy as a tool for detecting sleep in preterm infants, using polysomnography (PSG) as the "gold standard". A total of 10 neonates (mean [SD] 35.8 [1.2] weeks post-menstrual age; five female) hospitalised since birth for prematurity each participated in one 8-10 hr session during which PSG and actigraphy were recorded simultaneously. Inter-feed minute-by-minute PSG Sleep-Wake scores were compared to concurrent actigraph epochs categorised as either "Sleep" or "Wake" using three separate movement-per-minute thresholds (≤20, ≤40, ≤80). Tool validity was assessed using five metrics. A key finding was that for each of the movement thresholds there was high agreement rate, sensitivity, and predictive value of sleep (85.2%-97.2%), whereas specificity and predictive value of wake remained low (12%-46%). Receiver operating characteristic curve analysis also revealed low discriminatory power of actigraphy for estimating sleep (area under the curve = 0.636; Youden's Index J = 0.2173). Lack of sufficient minutes of autonomous wake periods among infants was identified as a key limitation in actigraphy. Findings from the present study suggest actigraphy cannot be validated for Sleep/Wake discrimination in preterm infants and that proper validation requires sufficient data from periods of both Sleep and Wake.

Infant sleep and negative reactivity: The role of maternal adversity and perinatal sleep

Sleep during infancy contributes to the development and maintenance of infant regulatory functioning and may be an early risk marker for more difficult temperamental traits like negative reactivity. Further, maternal adverse childhood experiences (ACEs) may predispose individuals to greater sleep disturbances in adulthood and have been linked with sleep disturbances in both mothers and infants. Thus, examining maternal history of ACEs and maternal sleep difficulties during pregnancy and postpartum may provide insight into underlying risk factors affecting infant sleep difficulties and early temperament development. Fifty-nine mothers from a diverse, community sample (44% white) completed questionnaires on ACEs, maternal sleep, infant sleep, and infant temperament at 30-weeks gestation, 6-weeks postpartum, and 16-weeks postpartum. Results indicated that maternal ACES and sleep problems during pregnancy have long term implications for infant negative reactivity at 16-weeks, with significant indirect effects through maternal and infant sleep problems at 6-weeks. Addressing psychosocial functioning and prenatal sleep during pregnancy, particularly among women with high ACEs, may be a target of intervention to improve maternal and infant sleep health during the postpartum, and reduce the risk for difficult infant temperament.

Roles for Sleep in Neural and Behavioral Plasticity: Reviewing Variation in the Consequences of Sleep Loss

Sleep is a vital physiological state that has been broadly conserved across the evolution of animal species. While the precise functions of sleep remain poorly understood, a large body of research has examined the negative consequences of sleep loss on neural and behavioral plasticity. While sleep disruption generally results in degraded neural plasticity and cognitive function, the impact of sleep loss can vary widely with age, between individuals, and across physiological contexts. Additionally, several recent studies indicate that sleep loss differentially impacts distinct neuronal populations within memory-encoding circuitry. These findings indicate that the negative consequences of sleep loss are not universally shared, and that identifying conditions that influence the resilience of an organism (or neuron type) to sleep loss might open future opportunities to examine sleep's core functions in the brain. Here, we discuss the functional roles for sleep in adaptive plasticity and review factors that can contribute to individual variations in sleep behavior and responses to sleep loss.

Sleep of infants and toddlers during 12 months of the COVID-19 pandemic in the midwestern United States

STUDY OBJECTIVES

Cultural sleep practices and COVID-19 mitigation strategies vary worldwide. The sleep of infants and toddlers during the COVID-19 pandemic in the United States (US) is understudied.

METHODS

Caregivers of children aged <3 years responded to a cross-sectional survey during 2020 (divided into quarters, with year quarter 1 largely pre-lockdown). We assessed the global effect of year quarter on parent-reported total sleep time (TST, hours) and sleep onset latency (SOL, hours) using ANOVA. We used multivariable linear regression to assess the adjusted effect of year quarter on TST, SOL and parental frustration. We used logistic regression to assess the adjusted effect of year quarter on nap consistency.

RESULTS

Of 594 children, mean age was 18.5±9.7 months; 52% were female. In the adjusted analyses, the reference categories were: quarter 1 (year quarter); ≤6 months (age category); <$25,000 (household income). TST was associated with age category (12 to ≤24 month: β=-2.86;p=0.0004, 24 to ≤36 month: β=-3.25;p<0.0001), and maternal age (β=-0.04;p=0.05). SOL was associated with year quarter (year quarter 3: β=0.16; p =0.04), age category (24 to ≤36 months: β=0.28;p<0.0001), household income ($100,000-150,000: β =-0.15;p=0.03, >$150,000: β=-0.19;p=0.01) and lack of room sharing (β=-0.09; p=0.05). Parental frustration with sleep increased with age (all p<0.05) and lack of room sharing (p=0.01). The effect of lack of room sharing on nap consistency approached significance (aOR 1.88;95%CI 0.95, 3.72).

CONCLUSIONS

Social factors such as lower household income and room sharing affected the sleep of US infants and toddlers as opposed to the COVID-19 lockdown itself.

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.

Self-Reported Sleep and Executive Function in Early Primary School Children

The study investigated the associations between children’s self-reported habitual sleep disturbance and multidimensional executive function (EF). Two hundred and four 7–9-year-old typically developing children completed the Sleep Self-Report and finished the Red-Blue Test, Wisconsin Card Sorting Test, and Backward Digit Span Test, indexing different EF components including inhibitory control, cognitive flexibility, and working memory. Results revealed that all the three EF components were significantly correlated with sleep. However, cognitive flexibility was no longer significantly related to sleep when the other EF components – inhibitory control and working memory – were controlled for. Meanwhile, inhibitory control, as well as working memory, was still significantly related to sleep after controlling for the other EF components. Results suggest that children’s self-reported sleep might be associated directly with inhibitory control and working memory, but indirectly with cognitive flexibility.

Nonrapid eye movement sleep characteristics and relations with motor, memory, and cognitive ability from infancy to preadolescence

Sleep plays a critical role in neural neurodevelopment. Hallmarks of sleep reflected in the electroencephalogram during nonrapid eye movement (NREM) sleep are associated with learning processes, cognitive ability, memory, and motor functioning. Research in adults is well-established; however, the role of NREM sleep in childhood is less clear. Growing evidence suggests the importance of two NREM sleep features: slow-wave activity and sleep spindles. These features may be critical for understanding maturational change and the functional role of sleep during development. Here, we review the literature on NREM sleep from infancy to preadolescence to provide insight into the network dynamics of the developing brain. The reviewed findings show distinct relations between topographical and maturational aspects of slow waves and sleep spindles; however, the direction and consistency of these relationships vary, and associations with cognitive ability remain unclear. Future research investigating the role of NREM sleep and development would benefit from longitudinal approaches, increased control for circadian and homeostatic influences, and in early childhood, studies recording daytime naps and overnight sleep to yield increased precision for detecting age-related change. Such evidence could help explicate the role of NREM sleep and provide putative physiological markers of neurodevelopment.

Effects of Touchscreen Media Use on Toddlers' Sleep: Insights from Longtime ECG Monitoring

Wearable biomedical sensor technology enables reliable monitoring of physiological data, even in very young children. The purpose of the present study was to develop algorithms for gaining valid physiological indicators of sleep quality in toddlers, using data from an undisturbing and easy-to-use wearable device. The study further reports the application of this technique to the investigation of potential impacts of early touchscreen media use. Toddlers' touchscreen media use is of strong interest for parents, educators, and researchers. Mostly, negative effects of media use are assumed, among them, disturbances of sleep and impairments of learning and development. In 55 toddlers (32 girls, 23 boys; 27.4 ± 4.9 months; range: 16-37 months), ECG monitoring was conducted for a period of 30 (±3) h. Parents were asked about their children's touchscreen media use and they rated their children's sleep quality. The use of touchscreen media predicted the physiologically determined quality of sleep but not parent-reported sleep quality (such as sleep onset latency). Greater heart rate differences between restless sleep phases and restful sleep indicated poorer nighttime recovery in children with more frequent use of touchscreen media. The study demonstrates that the expert analysis of the ECG during sleep is a potent tool for the estimation of sleep quality in toddlers.

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.

Prior sleep timing and visual recognition of emotional faces in 6-month-old infants

Face recognition is an important mnemonic ability for infants when navigating the social world. While age-related changes in face processing abilities are relatively well documented, less is known about short-term intra-individual fluctuations in this ability. Given that sleep deprivation in adults leads to impairments in information processing, we assessed the role of prior sleep on 6-month-old infants' (N = 17) visual recognition of faces showing three emotional expressions (neutral, sad, angry). Visual recognition was inferred by assessing novelty preferences for unfamiliar relative to familiarized faces in a visual recognition memory paradigm. In a within-subject design, infants participated once after they had recently woken up from a nap (nap condition) and once after they had been awake for an extended period of time (awake condition). Infants failed to show visual recognition for the neutral faces in either condition. Infants showed recognition for the sad and angry faces when tested in the awake condition, but not in the nap condition. This suggests that timing of prior sleep shapes how effectively infants process emotionally relevant information in their environment.

Nap timing makes a difference: Sleeping sooner rather than later after learning improves infants' locomotor problem solving

Twenty-nine newly-walking infants who had recently given up crawling trained to navigate a shoulder-height, nylon tunnel to reach a caregiver waiting at the other end. Infants in the Nap First group napped within 30 min of initial training. Infants in the Delay First group napped four hours after training. All infants were retested six hours after training on the same locomotor problem. Learning was measured by the number of training prompts required to solve the task, exploration, and time to solve the problem. Nap First infants benefited the most from a nap; they required fewer training prompts, used fewer posture shifts from training to test, and solved the task faster compared to Delay First infants, suggesting that optimally timed sleep does not merely protect against interference, but actively contributes to memory consolidation. This study highlights the importance of nap timing as a design feature and was a first step towards limit-testing the boundaries of the relation between sleep and learning. Infants' fragile memories require regular consolidation with intermittent periods of sleep to prevent interference or forgetting.

Association between mothers' fish intake during pregnancy and infants' sleep duration: a nationwide longitudinal study-The Japan Environment and Children's Study (JECS)

Purpose

N-3 polyunsaturated fatty acids (n-3 PUFAs), which are an important nutrient for humans, are particularly essential to the growth and development of the central nervous system (CNS) in fetuses and infants. Consequently, sufficient n-3 PUFA intake by mothers during pregnancy is considered to contribute to CNS development in their infants. CNS development is known to be associated with sleep, but no large epidemiological studies have yet confirmed that n-3 PUFA intake during pregnancy is associated with infants’ sleep.

Methods

After exclusion and multiple imputation from a dataset comprising 104 065 records from the Japan Environment and Children’s Study (JECS), we examined 87 337 mother–child pairs for the association between mothers’ fish and n-3 PUFA intakes and risk of their infants sleeping less than 11 h at 1 year of age.

Results

Multiple logistic regression analysis with the lowest quintile used as a reference revealed odds ratios for the second through fifth quintiles of 0.81 (95% confidence interval [95% CI] 0.76–0.87), 0.81 (95% CI 0.76–0.87), 0.78 (95% CI 0.72–0.84), and 0.82 (95% CI 0.76–0.88) for fish intake (p for trend < 0.001) and 0.90 (95% CI 0.84–0.97), 0.88 (95% CI 0.81–0.94), 0.88 (95% CI 0.82–0.95), and 0.93 (95% CI 0.86–0.998) for n-3 PUFA intake (p for trend = 0.04).

Conclusions

Low fish intake during pregnancy may increase the risk of infants sleeping less than 11 h at 1 year of age. This relationship may have been mediated by maternal n-3 PUFA intake and infant neurodevelopment, but further evidence from interventional and other studies is needed to determine the appropriate level of fish intake during pregnancy.

Trial registration

The Japan Environment and Children’s Study, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000035091 (Registration no. UMIN000030786).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02671-4.

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.

Mental health and sleep habits/problems in children aged 3-4 years: a population study

Background

Sleep is essential for mental health at all ages, but few studies have investigated the importance of sleep for mental health in early childhood. Therefore, this study examined the association between mental health and sleep habits/problems in children aged 34 years.

Methods

Children aged 3 to 4 years who were living in the community (n=415; 211/204 boys/girls) were recruited for this study. Their mental health was assessed using the Strengths and Difficulties Questionnaire (SDQ), and their sleep habits/problems were evaluated using the Child and Adolescent Sleep Checklist.

Results

Based on the total difficulties score of the SDQ, the children were divided into two groups: a poor mental health group (n=76) and a control group (n=339). In terms of sleep habits, which included total sleep time, bedtime, wake time, and nap conditions, there were no differences between the two groups. Regarding sleep-related problems, however, anxiety before going to sleep (p=0.026), circadian rhythm abnormalities (p=0.014), and sleepiness during classes outside of naptimes (p=0.031) were significantly higher in the poor mental health group than in the control group. Multiple regression analysis showed that poor mental health status was significantly associated with sleepiness and snoring (p=0.017 and p=0.018, respectively).

Conclusions

The mental health status of 34-year-old children was associated with sleep-related problems, namely sleepiness and snoring. Healthcare providers should pay attention to childrens irregular sleep-wake patterns; moreover, interventions for appropriate sleep hygiene will reduce the psychological burden on both children and their families.

Reviewing Evidence for the Relationship of EEG Abnormalities and RTT Phenotype Paralleled by Insights from Animal Studies

Rett syndrome (RTT) is a rare neurodevelopmental disorder that is usually caused by mutations of the MECP2 gene. Patients with RTT suffer from severe deficits in motor, perceptual and cognitive domains. Electroencephalogram (EEG) has provided useful information to clinicians and scientists, from the very first descriptions of RTT, and yet no reliable neurophysiological biomarkers related to the pathophysiology of the disorder or symptom severity have been identified to date. To identify consistently observed and potentially informative EEG characteristics of RTT pathophysiology, and ascertain areas most worthy of further systematic investigation, here we review the literature for EEG abnormalities reported in patients with RTT and in its disease models. While pointing to some promising potential EEG biomarkers of RTT, our review identify areas of need to realize the potential of EEG including (1) quantitative investigation of promising clinical-EEG observations in RTT, e.g., shift of mu rhythm frequency and EEG during sleep; (2) closer alignment of approaches between patients with RTT and its animal models to strengthen the translational significance of the work (e.g., EEG measurements and behavioral states); (3) establishment of large-scale consortium research, to provide adequate Ns to investigate age and genotype effects.

Atopic diseases in children and adolescents are associated with behavioural difficulties

Background

Atopic diseases and behavioural difficulties in children have both been on the rise in recent decades. This study seeks to assess associations between atopic diseases and behavioural difficulties, examining the differences considering child age and how behavioural difficulties were reported (via self-report or parent-report).

Methods

Data on behavioural difficulties, assessed through the Strengths and Difficulties Questionnaire (SDQ), and on atopic diseases, assessed through the participant’s medical history, were available for 2701 study participants aged 3 to 18 years. Associations between atopic diseases and behavioural difficulties were evaluated using linear regression analyses. We split the study sample into two groups. I: 3-to 10-year-olds/parent-reported SDQ (n = 1764), II: 11- to 18-year-olds/parent-reported SDQ (n = 937) and self-reported SDQ (n = 915). All analyses were adjusted for age, gender, and socioeconomic status.

Results

In younger children, atopic dermatitis was strongly associated with higher total difficulties scores, more emotional problems and conduct problems, and more symptoms of hyperactivity/inattention. Parents reported higher total difficulties scores, more emotional problems, and more peer-relationship problems for adolescents with bronchial asthma and other allergies, whereas the adolescents themselves reported more peer relationship problems.

Conclusion

In younger children, atopic dermatitis is associated with internalizing and externalizing problems. In adolescents, bronchial asthma and other allergies are associated with a greater level of internalizing problems only. The findings further suggest that parents of adolescents are more likely to perceive associations between atopic diseases and behavioural difficulties than the adolescents themselves.

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.

The Role of Sleep in Young Children's Development: A Review

This review article provides an overview of studies highlighting the importance of sleep in young children's development and summarizes research-based strategies for implementing healthy sleep practices. Sleep problems are common among young children and is one of the most commonly expressed concerns reported by caregivers. Insufficient sleep, poor sleep quality, and irregular sleep schedules may affect children's physical health, cognitive capacity, socioemotional processes, and behavioral functioning, with implications for children's development and well-being. Family context and factors, confounded with cultural variables, play a critical role in children's sleep behavior and practices. This article presents research-based recommendations to enhance knowledge about children's sleep and to promote appropriate practices.