III. SLEEP ASSESSMENT METHODS

Longitudinal associations between adolescents' sleep and adjustment: Respiratory sinus arrhythmia as a moderator

Sleep and autonomic nervous system functioning are important bioregulatory systems. Poor sleep and low baseline respiratory sinus arrhythmia (RSA), a measure of parasympathetic nervous system activity, are associated with externalizing behaviors and depressive symptoms in youth. Rarely, however, have measures of these systems been examined conjointly. The present study examined baseline RSA (RSA-B) as a moderator of longitudinal relations between adolescent sleep and adjustment. Participants were 256 adolescents (52% girls, 66% White/European American, 34% Black/African American) from small towns and surrounding rural communities in the southeastern United States. Sleep (minutes, efficiency, variability in minutes and efficiency) was assessed at age 15 via actigraphs across seven nights. RSA-B was derived from electrocardiogram data collected at rest. Adolescents self-reported externalizing problems and depressive symptoms at ages 15 and 17. Controlling for age 15 adjustment, findings generally demonstrated that sleep predicted age 17 adjustment particularly at higher (rather than lower) levels of RSA-B, such that adolescents with good sleep (more minutes and lower variability) and high RSA-B were at lowest risk for maladjustment. The results highlight the value of examining multiple bioregulatory processes conjointly and suggest that promoting good sleep habits and regulation of physiological arousal should support adolescent adjustment.

Dietary glycemic index and glycemic load in association with sleep duration: YaHS-TAMYZ and Shahedieh observational studies

BACKGROUND & AIMS

Current data on the association between dietary glycemic index (GI) and glycemic load (GL) and sleep duration are limited and controversial. The present cross-sectional study aimed to investigate the relationship between dietary GI and GL with sleep duration in a large number of adults living in central Iran.

METHODS

Baseline data from two Iranian cohorts were pooled for the current analysis: the YaHS-TAMYZ (n = 9962) and Shahedieh (n = 9977) studies. Demographic data as well as dietary intakes, sleep duration, and possible confounders, were collected by interview. Anthropometric measurements were also conducted by trained interviewers. Participants were categorized based on sleep duration [short (<6 h), normal (6-8 h), and long (>8 h)]. Multivariable logistic regression was used to determine the relationship between dietary GI/GL and the likelihood of short and long sleep duration.

RESULTS

In total, 10,451 participants aged 20-70 years were included in the analyses. After controlling for all possible confounders, no significant association was observed between dietary GI and short or long sleep duration (P > 0.05). Individuals in the highest quartile of dietary GL had a higher chance for long sleep duration compared to participants in the lowest quartile (OR = 1.41; 95% CI: 1.14, 1.74, P_trend = 0.001). No significant association was observed between dietary GL and short sleep duration.

CONCLUSION

Dietary GL is positively associated with the likelihood of long sleep duration. Future prospective studies are required to confirm the current findings.

Infant diurnal cortisol predicts sleep

The sleep-wake system is immature at birth and develops in parallel with the hypothalamic-pituitary-adrenal axis, a biological stress system of which the end product is cortisol. Perturbations in one system during infancy can maladaptively influence the maturation of the other system, leading to lasting sleep and cortisol system dysregulation and heightening the risk of enduring health problems. To better understand the early interplay between these systems, we examined whether actigraphy-derived measures of night-time sleep duration and onset were associated with cumulative exposure to cortisol, indexed by hair cortisol concentration, in 12-month-old children. Overall, early sleep onset predicted lower hair cortisol above and beyond sleep duration, family income and chaos experienced at home. Furthermore, both sleep and cortisol levels vary day to day, and temporal dependencies between daily sleep and cortisol regulation are not well understood. Thus, we assessed how the sleep characteristics on a particular evening related to salivary cortisol levels the following day and how daytime and evening cortisol related to the sleep characteristics on the same night. Lower total exposure to cortisol on a particular day was related to longer night-time sleep duration the same night, but not sleep onset. Lower salivary cortisol levels on a given evening related to earlier sleep onset the same night, but not to night-time sleep duration. Sleep duration and onset on a given night were unrelated to total cortisol exposure the following day. Findings suggest that in early development, the day-to-day relation between sleep and cortisol is not bidirectional, but more driven by diurnal cortisol.

Heritability of Sleep and Its Disorders in Childhood and Adolescence

Purpose of Review

This review summarizes recent literature on the heritability of sleep and sleep disorders in childhood and adolescence. We also identify gaps in the literature and priorities for future research.

Recent Findings

Findings indicate that age, measurement method, reporter, and timing of sleep measurements can influence heritability estimates. Recent genome-wide association studies (GWAS) have identified differences in the heritability of sleep problems when ancestral differences are considered, but sample sizes are small compared to adult GWAS. Most studies focus on sleep variables in the full range rather than on disorder. Studies using objective measures of sleep typically comprised small samples.

Summary

Current evidence demonstrates a wide range of heritability estimates across sleep phenotypes in childhood and adolescence, but research in larger samples, particularly using objective sleep measures and GWAS, is needed. Further understanding of environmental mechanisms and the interaction between genes and environment is key for future research.

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.

Actigraphic sleep and cortisol in middle childhood: A multivariate behavioral genetics model

To date, behavioral genetic studies investigated either sleep or cortisol levels in middle childhood, but not both simultaneously. Therefore, a pertinent question is the degree to which genetic factors and environmental factor contribute to the correlation between sleep and cortisol levels. To address this question, we employed the classical twin design. We measured sleep in 6-9-year-old twins (N = 436 twin pairs, “Together Unique” study) over four consecutive nights using actigraphy, and we measured morning cortisol on two consecutive days. Sleep duration, sleep efficiency, and wake episodes were used as indicators of sleep. Morning cortisol level was used as cortisol indicator. A structural equation model was fitted to estimate the contribution of additive genetic effects (A), shared (common) environmental effects, (C) and unique environmental effects (E) to phenotypic variances and covariances. Age, cohort, and sex were included as covariates. The heritability of sleep duration, sleep efficiency, and wake episodes were 52%, 45%, and 55%, respectively. Common environmental factors played no significant role. High genetic correlations between sleep duration and sleep efficiency and high genetic correlations between sleep efficiency and wake episodes were found. Shared environmental (29%) and unique environmental factors (53%) explained the variance in morning cortisol levels. Because the sleep and cortisol measures were found to be uncorrelated, we did not consider genetic and environmental contributions to the association between the sleep and cortisol measures. Our findings indicate that sleep duration, sleep efficiency, and wake episodes in children are mostly impacted by genetic factors and by unique environmental factors (including measurement error).

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Sleep duration, efficiency and wake episodes are moderately heritable.

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A high genetic correlation underlies sleep duration and sleep efficiency.

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A high genetic correlation underlies sleep efficiency and wake episodes.

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Cortisol and sleep were not (genetically) correlated.

Nighttime sleep and physical activity in 6-7 month-old infants

This study examined associations between objectively-measured nighttime sleep duration and physical activity in a sample of 6-7 month-old infants (N=93). The study also investigated relationships between infant sleep and demographic and environmental characteristics. Cross-sectional relationships were assessed using linear regression analyses. Nighttime sleep duration was positively associated with physical activity levels. Nighttime sleep duration was greater when infants had a consistent bedtime, slept in a separate room, were male, and had mothers who reported having a college education or greater. These findings can inform the development of interventions that aim to improve infant sleep.

Sleep Measurement in Children-Are We on the Right Track?

Sleep plays a critical role in the development of healthy children. Detecting sleep and sleep disorders and the effectiveness of interventions for improving sleep in children require valid sleep measures. Assessment of sleep in children, in particular infants and young children, can be a quite challenging task. Many subjective and objective methods are available to evaluate various aspects of sleep in childhood, each with their strengths and limitations. None can, however, replace the importance of thorough clinical interview with detailed history and clinical examination by a sleep specialist.

A longitudinal study of the links between maternal and infant nocturnal wakefulness

STUDY OBJECTIVES

To examine the longitudinal links between maternal and infant nocturnal wakefulness by employing a trajectory-based approach, and to assess whether the strength of these links differs as a function of sleep assessment method (actigraphy vs. self-report) and sleeping arrangements.

METHODS

Maternal and infant nocturnal wakefulness were assessed with actigraphy and sleep diaries at home for 5 nights, at 3 (N = 191), 6 (N = 178), 12 (N = 155), and 18 (N = 135) months postpartum. Outcome measures included the number of night-wakings (NW) and the length of nocturnal wakefulness (WASO).

RESULTS

Strong associations between maternal and infant nocturnal wakefulness (controlling for nighttime breastfeeding) were found for NW and WASO. Trajectory analyses demonstrated that the strength of these relations decreased linearly from 3 to 18 months. Furthermore, the findings showed that the links between maternal and infant NW and WASO were stronger for maternal reports than for actigraphy. No consistent differences were found in the strength of the relations between maternal and infant NW and WASO as a function of sleeping arrangements (ie, room-sharing vs. solitary-sleeping families).

CONCLUSIONS

The results suggest that infant and maternal sleep are strongly intertwined, especially during the first 6 months. The decline in the synchronization between maternal and infant nocturnal wakefulness through infant development may be attributed to the growing ability of infants to self-soothe during the night. The findings emphasize the need to study sleep within a family context.

Exposure to peer aggression and adolescent sleep problems: Moderation by parental acceptance

Many adolescents experience or witness aggression by peers at school. The purpose of the current study was to examine associations between exposure to peer aggression (i.e., peer victimization and witnessing school violence) and sleep problems and whether these associations are moderated by parental acceptance. Participants included 272 adolescents attending high school (M age = 17.27 years; 49% female; 59% White/European American, 41% Black/African American). Adolescents reported on exposure to peer aggression, parental acceptance, and two key sleep domains: sleep quality problems and daytime sleepiness. Results indicated that exposure to peer aggression was directly associated with poor sleep quality and sleepiness. Furthermore, peer victimization and witnessing school violence interacted with parental acceptance to predict sleep quality. Specifically, exposure to peer aggression was associated with sleep quality problems at higher (but not lower) levels of parental acceptance. The lowest levels of sleep quality problems were apparent at low levels of peer aggression and high levels of parental acceptance, but parental acceptance did not protect adolescents with high exposure to peer aggression against sleep problems. Findings illustrate the importance of considering moderators of effects and the conjoint roles of family and peer processes when considering individual differences in adolescents' sleep. Future research should examine whether parental strategies targeted to address peer victimization are protective against the detrimental effects of exposure to peer aggression. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Stress and Sleep Across the Onset of the COVID-19 Pandemic: Impact of Distance Learning on U.S. College Students' Health Trajectories

Study Objectives

This study examined associations between average and intraindividual trajectories of stress, sleep duration, and sleep quality in college students before, during, and after transitioning to online learning due to the COVID-19 pandemic.

Methods

One hundred and sixty-four first-year college students answered twice-weekly questionnaires assessing stress exposure and perception, sleep duration, and sleep quality from January until May, 2020 (N=4,269 unique observations).

Results

Multilevel growth modeling revealed that prior to distance learning, student stress was increasing and sleep duration and quality were decreasing. After transitioning online, students’ stress exposure and perception trajectories immediately and continuously decreased; sleep quality initially increased but decreased over time; and sleep duration increased but then plateaued for the remainder of the semester. Days with higher stress exposure than typical for that student were associated with lower sleep quality, and both higher stress exposure and perception at the transition were linked with simultaneous lower sleep quality. Specific groups (e.g., females) were identified as at-risk for stress and sleep problems.

Conclusion

Although transitioning to remote learning initially alleviated college students’ stress and improved sleep, these effects plateaued, and greater exposure to academic, financial, and interpersonal stressors predicted worse sleep quality on both daily and average levels. Environmental stressors may particularly dictate sleep quality during times of transition, but adaptations in learning modalities may help mitigate short-term detrimental health outcomes during global emergencies, even during a developmental period with considerable stress vulnerability. Future studies should examine longer-term implications of these trajectories on mental and physical health.

COVID-19 babies: auto-videosomnography and parent reports of infant sleep, screen time, and parent well-being in 2019 vs 2020

OBJECTIVE

The COVID-19 pandemic has profoundly impacted families, yet studies on its effects on infants and their parents have thus far been sparse and based mostly on retrospective parent reporting. This study aimed to prospectively evaluate the impact of COVID-19 living conditions on infant and parent sleep, as well as infant screen exposure, parent daytime sleepiness, and parent depression levels, using multi-method assessment.

METHODS

Infant and parent data collected in 2020 were compared with a matched cohort collected in 2019. The total sample included 1518 US infants aged 1-18 months (M = 8.5, SD = 4.6; 54% boys). Auto-videosomnography metrics were obtained from the 14-day period prior to survey completion (number of analyzed nights: M = 12.11 SD = 2.66 in the 2019 cohort; and M = 11.91 SD = 2.41 in the 2020 cohort). Parents completed online questionnaires regarding their infant's sleep and screen exposure, as well as their own sleep quality, daytime sleepiness, and depression levels.

RESULTS

Compared to 2019, infants in 2020 slept ∼40 min more per night on average, as indicated by auto-videosomnography. Infants additionally had earlier sleep timing, and increased parent-reported sleep-onset latency and nocturnal wakefulness. Infant screen time rose by 18.3 min per day for older infants, but remained stable for younger infants. Parents reported lower daytime sleepiness and higher depression symptomology during 2020, whereas no change was apparent in their sleep quality ratings.

CONCLUSIONS

Restricted living conditions during COVID-19 in the USA led to increased infant screen exposure and parental depression, but also to increased infant sleep duration and reduced parent sleepiness. Future research is needed to examine the mechanistic pathways through which COVID-19 impacted on infant and parent well-being.

Documentation of Sleep Hygiene With Melatonin Use in Management of Sleep Disturbance in Children With Neurodevelopmental Disorders: A Quality Improvement Project

INTRODUCTION

The purpose of this quality improvement project was to improve health-care provider consistency in addressing and documenting the use of sleep hygiene in children with neurodevelopmental disorders in alignment with evidence-based strategies.

METHOD

The project took place over 12 weeks and used a parent-completed screening tool and SmartPhrase technology incorporated into the patient note and discharge summary. A preimplementation and postimplementation query of the electronic medical record was used to determine change effectiveness.

RESULTS

The postimplementation query found a 42% increase in documentation of sleep hygiene. In addition, a 55% increase in documentation of sleep hygiene with the initiation of melatonin was noted.

DISCUSSION

The increase in documentation supports success of this initial practice change and demonstrates adherence to evidence-based sleep hygiene strategies. The project provided evidence of a significant improvement in electronic medical record documentation, highlighting an increased awareness of sleep issues in children with neurodevelopmental disorders.

Video-based neonatal state assessment method for timing of procedures

BACKGROUND

Procedures should be performed when an infant is most receptive to disruptions in order to reduce the stress on the infant. However, frequent direct observations place a heavy burden on medical staff. There is therefore a need for a method for quantitatively and automatically evaluating the neonatal state.

METHODS

Ten infants in our hospital were enrolled in this study. The states of the infants were assessed by medical staff using the Brazelton Neonatal Behavioral Assessment Scale and were recorded on video at the same time. The recorded states were reclassified as activity levels, a new state classification method that includes middle activity, which is the appropriate time for a procedure. Using image analysis, motions of the infant were quantified as two indices: activity and pause time. Activity and pause time were compared for each activity level. The cutoff values of the indices were calculated, and the sensitivity and specificity of the middle activity were calculated.

RESULTS

There was a significant difference between all groups of activity level (P < 0.01). The maximum sensitivity and specificity of middle activity were 71.7% and 51.2%, respectively.

CONCLUSIONS

The neonatal state of infants can be quantitatively and automatically evaluated using video cameras, and the activity level can be used to determine an appropriate time for procedures in infants. This will reduce the burden on medical staff and lead to less stressful procedures for infants.

Sleep Disorders in Children With Autism Spectrum Disorder: Insights From Animal Models, Especially Non-human Primate Model

Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental disorder with deficient social skills, communication deficits and repetitive behaviors. The prevalence of ASD has increased among children in recent years. Children with ASD experience more sleep problems, and sleep appears to be essential for the survival and integrity of most living organisms, especially for typical synaptic development and brain plasticity. Many methods have been used to assess sleep problems over past decades such as sleep diaries and parent-reported questionnaires, electroencephalography, actigraphy and videosomnography. A substantial number of rodent and non-human primate models of ASD have been generated. Many of these animal models exhibited sleep disorders at an early age. The aim of this review is to examine and discuss sleep disorders in children with ASD. Toward this aim, we evaluated the prevalence, clinical characteristics, phenotypic analyses, and pathophysiological brain mechanisms of ASD. We highlight the current state of animal models for ASD and explore their implications and prospects for investigating sleep disorders associated with ASD.

Quality of father-child relationships as a predictor of sleep developments during preschool years

Substantial developmental changes in sleep occur during the preschool period, but few studies have investigated the factors that forecast these developments. The aim of this study was to examine whether three aspects of father-child relationships in toddlerhood predicted individual differences in developmental patterns of change in five actigraphy-derived sleep variables during the preschool period (N = 67; sleep assessed yearly between 2 and 4 years). In a predominantly White and middle-to-higher income sample, paternal mind-mindedness and quality of father-child interactions were assessed during father-child free play at 18 months and fathers self-reported on their involvement in childrearing at age 2. Multilevel growth modeling revealed that children whose father made more mind-related comments during father-child interactions had a higher proportion of sleep taking place during nighttime as well as shorter daytime and total sleep duration at 2 years. This was, however, followed by a relative leveling off (i.e., less rapid change) of these sleep features between 2 and 4 years. Given previous studies documenting that nighttime sleep proportion increases while daytime and total sleep duration decrease during preschool years, the findings suggest that children who are exposed to more paternal mind-mindedness may reach more mature sleep patterns earlier in development.

Linking autonomic nervous system reactivity with sleep in adolescence: Sex as a moderator

The purpose of the present study was to investigate relations between autonomic nervous system (ANS) reactivity across the parasympathetic and sympathetic branches and multiple sleep parameters in adolescence. Participants were 244 adolescents (Mage  = 15.79 years old, SD = 9.56 months; 67.2% White/European-American, 32.8% Black/African-American). Parasympathetic activity was indexed by respiratory sinus arrhythmia (RSA) withdrawal and sympathetic activity was indexed by skin conductance level reactivity (SCL-r), which were examined in response to a laboratory-based stressor (star-tracing task). Sleep was assessed with actigraphs in adolescents' homes for seven consecutive nights. Two sleep parameters were examined: sleep duration indexed by actual sleep minutes and sleep quality indexed by sleep efficiency from sleep onset to wake time. Regression analyses showed that more RSA withdrawal (lower RSA during task than baseline) was associated with shorter sleep, and more SCL-r (higher SCL during task than baseline) was associated with poorer sleep efficiency. Moderation analyses showed that associations linking RSA withdrawal with fewer sleep minutes and poorer sleep efficiency, and SCL-r with fewer sleep minutes were significant only for boys. Results illustrate that higher daytime physiological reactivity (increased RSA withdrawal and SCL-r) is negatively associated with sleep duration and efficiency for adolescents, especially boys.

Associations between cognitive function, actigraphy-based and self-reported sleep in older community-dwelling adults: Findings from the Irish Longitudinal Study on Ageing

OBJECTIVE

Cognitive impairment is prevalent in older ages. Associations with sleep are well established; however, ambiguity remains in which sleep characteristics contribute to this impairment. We examined cross-sectional associations between both self-reported and actigraphy-based sleep and cognitive performance across a number of domains in community-dwelling older adults.

METHODS

1520 participants aged 50 and older with self-reported and actigraphy-based total sleep time (TST) (≤5, 6, 7-8, 9 and ≥10 h) and self-reported sleep problems were analysed. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), verbal fluency, immediate and delayed recall memory, colour trails tests, and choice reaction tests (CRT). Associations between sleep and cognition were modelled using linear and negative binomial regression.

RESULTS

Negative associations were found between ≥10 h of self-reported TST and MoCA error rate (incidence rate ratio [IRR] = 1.42; 95% confidence interval [CI] = 1.18, 1.71; p < 0.001); verbal fluency (beta [B] = -2.32 words; 95% CI = -4.00, -0.65; p < 0.01); and delayed recall (B = -0.91 words; 95% CI = -1.58, -0.25; p < 0.05) compared to 7-8 h. Significant associations with actigraphy-based TST were limited to MoCA error rate in ≤5 h (IRR = 1.22; 95% CI = 1.02, 1.45; p < 0.05) compared to 7-8 h. Higher numbers of sleep problems were associated with slower performance in CRT cognitive response time (IRR = 1.02; 95% CI = 1.00, 104; p < 0.05) and total response time (IRR = 1.02; 95% CI = 1.00, 1.04; p < 0.05).

CONCLUSIONS

Self-reported long sleep duration was consistently associated with worse cognitive performance across multiple domains. Marginal associations between cognition and both actigraphy-based sleep and self-reported sleep problems were also apparent. These results further affirm poor sleep as a risk factor for cognitive impairment.

A meta-analysis of accelerometer sleep outcomes in healthy children based on the Sadeh algorithm: the influence of child and device characteristics

STUDY OBJECTIVES

Children often experience sleep problems, with a negative impact on mood, behavior, cognitive function, and other aspects of mental and physical health. Accelerometers are widely used to assess sleep, but general reference values for healthy children do not yet exist. The aim of this meta-analysis was to determine mean values for wake after sleep onset (WASO), sleep efficiency (SE), total sleep time (TST) and sleep onset latency (SOL), and to determine the effect of child and accelerometer-characteristics.

METHODS

A search included studies with healthy children, 0-18 years, reporting WASO, SE, TST, and/or SOL, calculated with the Sadeh algorithm. Meta-analyses with random effects produced pooled estimate means per outcome. Meta-regression analyses determined the effect of age, sex, placement site and accelerometer type.

RESULTS

Eighty-three studies (9,068 participants) were included. Pooled means were 63 min (95% CI 57 to 69) for WASO, 88% (95% CI 87 to 89) for SE, 477 min (95% CI 464 to 491) for TST and 19 min (95% CI 17 to 22) for SOL. Heterogeneity was high (95%-99%). TST decreased with age and there was an age-effect on SOL. SE differed between wrist and ankle (used in age 0-24 months) placement, and between piezoelectric and MEMS-type accelerometers. No differences were found between boys and girls, although this number of studies was small.

CONCLUSIONS

We found differences in almost all investigated outcomes and heterogeneity was high. Therefore, we advise to use a study-specific control sample until more robust reference values are available. Future research should narrow the methodological heterogeneity and produce larger datasets, needed to establish these reference values.

Trajectories of sleep problems in childhood: associations with mental health in adolescence

STUDY OBJECTIVES

We examined initial levels (intercepts) of sleep-wake problems in childhood and changes in sleep-wake problems across late childhood (slopes) as predictors of externalizing behavior problems, depressive symptoms, and anxiety in adolescence. To ascertain the unique effects of childhood sleep problems on adolescent mental health, we controlled for both childhood mental health and adolescent sleep problems.

METHODS

Participants were 199 youth (52% boys; 65% White/European American, 35% Black/African American). Sleep-wake problems (e.g. difficulty sleeping and waking up in the morning) were assessed during three time points in late childhood (ages 9, 10, and 11) with self-reports on the well-established School Sleep Habits Survey. At age 18, multiple domains of mental health (externalizing behavior problems, depressive symptoms, and anxiety) and sleep-wake problems were assessed.

RESULTS

Latent growth curve modeling revealed that children with higher levels of sleep-wake problems at age 9 had consistently higher levels of such problems between ages 9 and 11. The initial level of sleep-wake problems at age 9 predicted externalizing behaviors, depressive symptoms, and anxiety at age 18, controlling for mental health in childhood and concurrent sleep-wake problems in adolescence. The slope of sleep-wake problems from ages 9 to 11 did not predict age 18 mental health.

CONCLUSIONS

Youth who had higher sleep-wake problems during late childhood had higher levels of mental health problems in adolescence even after controlling for childhood mental health and concurrent sleep-wake problems. Findings illustrate that childhood sleep problems may persist and predict adolescent mental health even when potentially confounding variables are rigorously controlled.

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.

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.

Improving Stress Management and Sleep Hygiene in Intelligent Homes

High stress levels and sleep deprivation may cause several mental or physical health issues, such as depression, impaired memory, decreased motivation, obesity, etc. The COVID-19 pandemic has produced unprecedented changes in our lives, generating significant stress, and worries about health, social isolation, employment, and finances. To this end, nowadays more than ever, it is crucial to deliver solutions that can help people to manage and control their stress, as well as to reduce sleep disturbances, so as to improve their health and overall quality of life. Technology, and in particular Ambient Intelligence Environments, can help towards that direction, when considering that they are able to understand the needs of their users, identify their behavior, learn their preferences, and act and react in their interest. This work presents two systems that have been designed and developed in the context of an Intelligent Home, namely CaLmi and HypnOS, which aim to assist users that struggle with stress and poor sleep quality, respectively. Both of the systems rely on real-time data collected by wearable devices, as well as contextual information retrieved from the ambient facilities of the Intelligent Home, so as to offer appropriate pervasive relaxation programs (CaLmi) or provide personalized insights regarding sleep hygiene (HypnOS) to the residents. This article will describe the design process that was followed, the functionality of both systems, the results of the user studies that were conducted for the evaluation of their end-user applications, and a discussion about future plans.

The effect of napping and nighttime sleep on memory in infants

During the first year of life, infants devote the majority of their time to sleep. Research in adults has shown that sleep supports a variety of memory processes. Surprisingly, sleep's function for infant memory has only started to receive attention in research. In this chapter, we will describe age-related changes in sleep and in memory processing over the first years of life, as well as methods to capture both sleep and memory. Then, we will review current findings on the effects of sleep on memory processing in infants. Lastly, we will also point out gaps in current knowledge and describe potential avenues for future research. Overall, the results of recent experimental studies provide evidence that timely, extended napping is involved in how memories are encoded and stored in the long-term and contribute to the formation of knowledge networks in infants.

Socioeconomic Status and Sleep among Couples

Objective/Background: Lower socioeconomic status (SES) is generally associated with poor sleep but little is known about how different SES indices are associated with sleep duration and quality, or about these relations longitudinally or in cohabiting couples. The main objective was to examine longitudinal associations between multiple SES and sleep parameters in cohabiting adults. Participants: Participants were cohabiting couples (N = 135) of women (M age = 37.2 years, SD = 5.93; 76% White/European American, 18% Black/African American) and men (M = 39.9 years, SD = 7.33; 78% White, 18% Black). Methods: Men and women participated twice with a 1-year lag. At Time (T1), participants reported on multiple SES indices including their income, perceived economic well-being, education, employment status, and occupation. Sleep at T1 and T2 was assessed with self-reports and actigraphs (sleep duration from onset to wake time, %sleep from onset to wake, long wake episodes). Results: Actor effects on actigraphy-assessed sleep parameters were evident for both men and women; low SES was associated with shorter duration and poor quality (%sleep, long wake episodes) sleep. These associations were most pronounced for income-to-needs ratio (men and women) and perceived economic well-being (women only). Partner effects were also evident such that men's employment status was associated with women's longer sleep duration and greater sleep quality (%sleep) whereas women's employment predicted increased subjective sleep problems for men. Conclusion: Findings illustrate the need to consider multiple SES and sleep indices, as well as the family context in studies addressing linkages between SES and sleep.

Maternal stress during pregnancy alters fetal cortico-cerebellar connectivity in utero and increases child sleep problems after birth

Child sleep disorders are increasingly prevalent and understanding early predictors of sleep problems, starting in utero, may meaningfully guide future prevention efforts. Here, we investigated whether prenatal exposure to maternal psychological stress is associated with increased sleep problems in toddlers. We also examined whether fetal brain connectivity has direct or indirect influence on this putative association. Pregnant women underwent fetal resting-state functional connectivity MRI and completed questionnaires on stress, worry, and negative affect. At 3-year follow-up, 64 mothers reported on child sleep problems, and in the subset that have reached 5-year follow-up, actigraphy data (N = 25) has also been obtained. We observe that higher maternal prenatal stress is associated with increased toddler sleep concerns, with actigraphy sleep metrics, and with decreased fetal cerebellar-insular connectivity. Specific mediating effects were not identified for the fetal brain regions examined. The search for underlying mechanisms of the link between maternal prenatal stress and child sleep problems should be continued and extended to other brain areas.

Sleep disturbances and first onset of major mental disorders in adolescence and early adulthood: A systematic review and meta-analysis

Despite several high-quality reviews of insomnia and incidence of mental disorders, prospective longitudinal relationships between a wider range of sleep disturbances and first onset of a depressive, bipolar, or psychotic disorders during the peak age range for onset of these conditions has not been addressed. Database searches were undertaken to identify publications on insomnia, but also on other sleep problems such as hypersomnia, short sleep duration, self-identified and/or generic 'sleep problems' and circadian sleep-wake cycle dysrhythmias. We discovered 36 studies that were eligible for systematic review and from these publications, we identified 25 unique datasets that were suitable for meta-analysis (Number>45,000; age ∼17). Individuals with a history of any type of sleep disturbance (however defined) had an increased odds of developing a mood or psychotic disorder in adolescence or early adulthood (Odds ratio [OR]:1.88; 95% Confidence Intervals:1.67, 2.25) with similar odds for onset of bipolar disorders (OR:1.72) or depressive disorders (OR:1.62). The magnitude of associations differed according to type of exposure and was greatest for sleep disturbances that met established diagnostic criteria for a sleep disorder (OR: 2.53). However, studies that examined observer or self-rated symptoms, also reported a significant association between hypersomnia symptoms and the onset of a major mental disorder (OR:1.39). Overall study quality was moderate with evidence of publication bias and meta-regression identified confounders such as year of publication. We conclude that evidence indicates that subjective, observer and objective studies demonstrate a modest but significant increase in the likelihood of first onset of mood and psychotic disorders in adolescence and early adulthood in individuals with broadly defined sleep disturbances. Although findings support proposals for interventions for sleep problems in youth, we suggest a need for greater consensus on screening strategies and for more longitudinal, prospective studies of circadian sleep-wake cycle dysrhythmias in youth.

Mothers' sleep deficits and cognitive performance: Moderation by stress and age

There are well-known associations between stress, poor sleep, and cognitive deficits, but little is known about their interactive effects, which the present study explored in a sample of mothers of toddlers. Since certain types of cognitive decline start during the 20s and continue into later ages, we also explored whether mothers’ age interacted with stress and sleep in the prediction of cognitive functioning. We hypothesized that poorer sleep [measured using one week of 24-hour wrist actigraphy data] and having more chronic stressors [e.g., life events, household chaos, work/family role conflict] would be linked with poorer cognitive performance [both executive function and standardized cognitive ability tasks], and that the interactive combination of poorer sleep and more stressors would account for the effect. We also explored whether this process operated differently for younger versus older women. In a socioeconomically and geographically diverse community sample of 227 women with toddler-age children [age, M = 32.73 yrs, SD = 5.15 yrs], poorer cognitive performance was predicted by greater activity during the sleep period, shorter sleep duration, and lower night-to-night consistency in sleep; it was not associated with higher levels of stress. The interactive effects hypothesis was supported for sleep activity [fragmented sleep] and sleep timing [when mothers went to bed]. The combination of more exposure to stressors and frequent night waking was particularly deleterious for older women’s performance. For younger women, going to bed late was associated with poorer performance if they were experiencing high levels of stress; for those experiencing low levels of stress, going to bed late was associated with better performance.

The Validity, Reliability, and Feasibility of Measurement Tools Used to Assess Sleep of Pre-school Aged Children: A Systematic Rapid Review

Background: Sleep of pre-school aged children is important for their health and development, but there are currently no standards for measuring sleep in this age group. We aimed to examine the validity, reliability and feasibility of tools used to assess sleep of pre-school aged children. Methods: Studies were eligible for inclusion if they examined the validity and/or reliability and/or feasibility of a measurement tool used to examine sleep of pre-school aged children (aged 3-7 years). We systematically searched six electronic databases, grey literature and trial registries. We manually searched topic specific journals, reference and citations of included studies, and reference lists of existing reviews. We extracted data and conducted a risk of bias assessment on the included studies using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) risk of bias checklist. We used a narrative synthesis to present the results. Results: Sixteen studies met the inclusion criteria: these explored accelerometers (n = 3) and parental reported tools (n = 13; nine questionnaires, six diaries). Studies assessed construct validity (n = 3), criterion validity (n = 1), convergent validity (n = 13), test-retest reliability (n = 2), internal consistency (n = 4) and feasibility (n = 12). Most studies assessed the convergent validity of questionnaires and diaries compared with accelerometers, but the validity of accelerometers for sleep in this age group is unknown. Of studies with a low risk of bias, one sleep diary was shown to be valid for measuring sleep duration. No measurement tools were appropriate for determining sleep quality. Reporting of reliability and feasibility was minimal. Discussion: The evidence base in this field is limited, and most studies had high risk of bias. Future research on sleep in pre-school aged children should focus on assessing the validity, reliability and feasibility of accelerometers, which in turn will improve the quality of studies that assess questionnaires and diaries against accelerometers. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021230900; PROSPERO: CRD42021230900.

Sleep-Related Problems and Pediatric Anxiety Disorders

Sleep-related problems are highly prevalent among childhood and adolescent anxiety disorders. The objective of this review was to summarize the relevant clinical research literature as it pertains to the nature of the association between sleep-related problems and youth anxiety, developmental factors relevant to this association, and intervention efforts to target comorbid sleep challenges and anxiety. Limitations of the literature and future directions are discussed.

24-hour activity for children with cerebral palsy: a clinical practice guide

The association between physical activity and health has been clearly established, and the promotion of physical activity should be viewed as a cost-effective approach that is universally prescribed as a first-line treatment for nearly every chronic disease. Health care providers involved in the care for individuals with cerebral palsy (CP) are encouraged to take an active role in promoting their health and well-being. Balancing activity behaviours across the whole day, with improved physical activity, reduced sedentary time, and healthy sleep behaviours, can set up infants, preschool-, and school-aged children with CP for a healthy trajectory across their lifetime. However, most clinicians do not apply a systematic surveillance, assessment, and management approach to detect problems with physical activity or sleep in children with CP. Consequently, many children with CP miss out on an important first line of treatment. This article presents an evidence-informed clinical practice guide with practical pointers to help practitioners in detecting 24-hour activity problems as a critical step towards adoption of healthy lifestyle behaviours for children with CP that provide long-term health benefits.

Longitudinal correlates of sleep duration in young children

OBJECTIVE

The primary aim of this study was to longitudinally examine potential demographic and screen time correlates of nap duration, nighttime sleep duration, and total sleep duration in young children over two time points.

METHODS

Data from the supporting Healthy physical AcTive Childcare setting (HATCH) study were analyzed. Participants were 206 toddlers (19-35 months) and preschoolers (36-60 months) in Alberta and Ontario, Canada. Child age, screen time (television, video games), and sleep duration (nap, nighttime) were measured at baseline and six-month follow-up, while other demographic variables were assessed at baseline only using the HATCH parental questionnaire. Mixed models were performed to examine the associations between potential correlates and sleep duration over time.

RESULTS

In the multiple regression models, significant correlates of total sleep duration (min/d) were child age (months; B = -3.03; 95%CI:-3.88,-2.19) and parental education (bachelor's degree vs. below bachelor level; B = 29.74, 95%CI:7.43,52.06). Significant correlates of nighttime sleep duration (min/d) included child age (B = -0.81; 95CI%:-1.53,-0.10), child race/ethnicity (Caucasian vs. non-Caucasian; B = 15.31; 95%CI:0.38,30.25), household income (>$150,000 vs. <$50,000; B = 32.93, 95%CI:9.80,56.06), television time (B = -0.19, 95%CI:-0.32,-0.05), video games time (B = -0.19, 95%CI: -0.38, -0.01) and total screen time (B = -0.19; 95%CI:-0.29,-0.08). Significant correlates of nap duration (min/d) were child age (B = -2.10; 95%CI:-2.68,-1.51) and race/ethnicity (Caucasian vs. non-Caucasian; B = -13.73; 95%CI:-25.78,-1.68).

CONCLUSION

Young children who were non-Caucasian, from lower income families, who had less-educated parents, or who had more screen time tended to have shorter sleep duration. Targeting these demographic groups and screen time appears important for promoting adequate sleep duration in early childhood.

Which are the Central Aspects of Infant Sleep? The Dynamics of Sleep Composites across Infancy

Sleep during infancy is important for the well-being of both infant and parent. Therefore, there is large interest in characterizing infant sleep with reliable tools, for example by combining actigraphy with 24-h-diaries. However, it is critical to select the right variables to characterize sleep. In a longitudinal investigation, we collected sleep data of 152 infants at ages 3, 6, and 12 months. Using principal component analysis, we identified five underlying sleep composites from 48 commonly-used sleep variables: Sleep Night, Sleep Day, Sleep Activity, Sleep Timing, and Sleep Variability. These composites accurately reflect known sleep dynamics throughout infancy as Sleep Day (representing naps), Sleep Activity (representing sleep efficiency and consolidation), and Sleep Variability (representing day-to-day stability) decrease across infancy, while Sleep Night (representing nighttime sleep) slightly increases, and Sleep Timing becomes earlier as one ages. We uncover interesting dynamics between the sleep composites and demonstrate that infant sleep is not only highly variable between infants but also dynamic within infants across time. Interestingly, Sleep Day is associated with behavioral development and therefore a potential marker for maturation. We recommend either the use of sleep composites or the core representative variables within each sleep composite for more reliable research.

Hospital Environmental Effects on Sleep in Adults With Traumatic Brain Injury in Rehabilitation

PURPOSE

The aim of this study was to describe sleep patterns of adults with traumatic brain injury and examine effects of environmental stressors (patient care activities and light) on patterns of sleep.

DESIGN

A descriptive, correlational, explanatory design was used for this study.

METHODS

Sixty-three subjects with traumatic brain injury (>18 years) on an acute traumatic brain injury rehabilitation unit wore an Actiwatch for 48 hours to collect light and sleep data. Patient care activity data were collected between 11 p.m. and 7 a.m.

FINDINGS

Patient care activities and light occurred between 11 p.m. and 7 a.m. Nighttime sleep duration and sleep efficiency were explained by patient care activities, whereas light explained wake time after sleep onset.

CONCLUSION

Patient care activities and light serve as environmental stressors that affect sleep.

CLINICAL RELEVANCE

Results necessitate examining the need and timing of nursing care activities and light during nighttime. Findings provide a basis for policy changes that optimize sleep.

The contribution of good sleep to working memory in preschool: A matter of sleep quality or duration?

Good sleep is essential for efficient cognitive performance. The present research examined the link between sleep and working memory (WM) during early childhood, a period of major advances in neurodevelopment. The sample included 80 healthy children, 40 3-year-olds and 40 4-year-olds, attending childcare settings. The children were individually tested using WM tasks; parents completed sleep questionnaires. On a group level, WM improved with age. Process model analysis demonstrated the effect of age on WM (P=0.001) and indicated an age-specific involvement of sleep quality (P=0.01). Whereas sleep duration was not associated with WM, at 4years of age, sleep disturbance with physical symptoms (e.g., breathing, motor) was associated with poor WM performance. Among 3-year-old girls, fear-related sleep disruption was associated with better WM performance. Together, the results suggest that the association between sleep and WM is dependent on: (a) specific aspects of sleep, (b) age, and (c) gender. More research is essential for unraveling the underlying neuro-maturational processes and mechanisms.

Ear-EEG for sleep assessment: a comparison with actigraphy and PSG

PURPOSE

To assess automatic sleep staging of three ear-EEG setups with different electrode configurations and compare performance with concurrent polysomnography and wrist-worn actigraphy recordings.

METHODS

Automatic sleep staging was performed for single-ear, single-ear with ipsilateral mastoid, and cross-ear electrode configurations, and for actigraphy data. The polysomnography data were manually scored and used as the gold standard. The automatic sleep staging was tested on 80 full-night recordings from 20 healthy subjects. The scoring performance and sleep metrics were determined for all ear-EEG setups and the actigraphy device.

RESULTS

The single-ear, the single-ear with ipsilateral mastoid setup, and the cross-ear setup performed five class sleep staging with kappa values 0.36, 0.63, and 0.72, respectively. For the single-ear with mastoid electrode and the cross-ear setup, the performance of the sleep metrics, in terms of mean absolute error, was better than the sleep metrics estimated from the actigraphy device in the current study, and also better than current state-of-the-art actigraphy studies.

CONCLUSION

A statistically significant improvement in both accuracy and kappa was observed from single-ear to single-ear with ipsilateral mastoid, and from single-ear with ipsilateral mastoid to cross-ear configurations for both two and five-sleep stage classification. In terms of sleep metrics, the results were more heterogeneous, but in general, actigraphy and single-ear with ipsilateral mastoid configuration were better than the single-ear configuration; and the cross-ear configuration was consistently better than both the actigraphy device and the single-ear configuration.

Applied behavior analysis measurement, assessment, and treatment of sleep and sleep-related problems

This discussion article considers applied behavior analysis measurement, assessment, and treatment of sleep and sleep-related problems among infants, children, and youth who are typically developing and have neurodevelopmental disabilities. Measurement has concentrated on designing practitioner-implemented methods and improving fidelity of data recording through sleep-monitoring instrumentation. The emphasis of assessment is identifying antecedent and consequence variables that promote sleep and evoke and maintain sleep-related problems. Treatment research has evaluated several effective interventions for problems such as delayed sleep-onset, night and early morning waking, bedtime resistance, and unwanted co-sleeping. Early and contemporary applied behavior analysis research is reviewed relative to function-based treatment formulation, intervention integrity, social validity, and research-to-practice translation.

Patterns of infant-only wake bouts and night feeds during early infancy: An exploratory study using actigraphy in mother-father-infant triads

BACKGROUND

Infants' ability to fall back to sleep without parental involvement may reduce nighttime feeding frequency.

OBJECTIVE

We describe the associations between infant-only wake bouts ("self-soothing") and nighttime feeds using actigraphy from 6 to 24 weeks of age.

METHODS

Mother-father-infant triads (N = 20) wore sleep monitors, and mothers recorded infant night feeds, when infants were 6, 15 and 24 weeks of age. Actigraphy data were matched within-families to quantify infant-only wake bouts (infants woke; mothers/fathers remained asleep). Mixed models tested associations between infant-only wake bouts and night feeding frequency.

RESULTS

The proportion of infant-only wake bouts/night increased from 6 to 15 weeks of age (6 weeks: 52% [95% CI: 45-59]; 15 weeks: 64% [57-71]; 24 weeks: 62% [55-69]; P < .01). For every 10% increase in the proportion of infant-only wake bouts/night, there were 0.36 fewer feeds/night (P < .01) at 24 weeks; these concurrent associations were not found at 6 and 15 weeks. The proportion of infant-only wake bouts/night at 6 weeks predicted a faster rate of decline in the number of feeds/night from 6 to 24 weeks (P < .01).

CONCLUSION

Infants' ability to fall back to sleep without parent involvement at 6 weeks was associated with the trajectory of nighttime feeding frequency across early infancy.

Noninvasive three-state sleep-wake staging in mice using electric field sensors

STUDY OBJECTIVE

Validate a novel method for sleep-wake staging in mice using noninvasive electric field (EF) sensors.

METHODS

Mice were implanted with electroencephalogram (EEG) and electromyogram (EMG) electrodes and housed individually. Noninvasive EF sensors were attached to the exterior of each chamber to record respiration and other movement simultaneously with EEG, EMG, and video. A sleep-wake scoring method based on EF sensor data was developed with reference to EEG/EMG and then validated by three expert scorers. Additionally, novice scorers without sleep-wake scoring experience were self-trained to score sleep using only the EF sensor data, and results were compared to those from expert scorers. Lastly, ability to capture three-state sleep-wake staging with EF sensors attached to traditional mouse home-cages was tested.

RESULTS

EF sensors quantified wake, rapid eye movement (REM) sleep, and non-REM sleep with high agreement (>93%) and comparable inter- and intra-scorer error as EEG/EMG. Novice scorers successfully learned sleep-wake scoring using only EF sensor data and scoring criteria, and achieved high agreement with expert scorers (>91%). When applied to traditional home-cages, EF sensors enabled classification of three-state (wake, NREM and REM) sleep-wake independent of EEG/EMG.

CONCLUSIONS

EF sensors score three-state sleep-wake architecture with high agreement to conventional EEG/EMG sleep-wake scoring 1) without invasive surgery, 2) from outside the home-cage, and 3) and without requiring specialized training or equipment. EF sensors provide an alternative method to assess rodent sleep for animal models and research laboratories in which EEG/EMG is not possible or where noninvasive approaches are preferred.

Comparison of sleep problems between term and preterm born preschool children

OBJECTIVES

Sleep disorders are common problems among all age groups. If sleep problems detected in childhood are not resolved successfully, they become sleep disorders and a chronic state. In this study, we aimed to compare sleep problems between preterm-born and term-born preschool-age children.

METHODS

In the cross-sectional study, children were grouped according to whether they were born preterm or at term. The preterm group included 137 children aged four to six years. The control group comprised 145 age-matched term-born preschool children. The prenatal, natal, demographical, and clinical characteristics of preterm- and term-born preschool-age children were compared. The Children's Sleep Habits Questionnaire (CSHQ) was used to identify sleep problems. The total score and subscores of the CSHQ were compared between the groups.

RESULTS

The percentage of gastroesophageal reflux (GER) symptoms and obstructive sleep apnea (OSA) symptoms were significantly higher in the preterm group. According to the cutoff point of the CSHQ, 97 children in the preterm group (70.8%) and 88 children in the control group (60.7%) had a sleep disorder. The total score of the CSHQ was significantly higher in the preterm group compared with the control group; however, the scores of the subscales were similar between the groups. In the regression analysis, a significant association was found between being born preterm and having sleep disorder (β = 0.308, OR = 1.36, p = 0.04).

CONCLUSIONS

Our study reported a high percentage of sleep problems in preterm-born preschool children. We suggest that prematurity is associated with sleep problems even if the etiology of sleep problems is heterogeneous. Symptoms regarding GER and OAS should be investigated, and precautions, such as prohibiting maternal cigarette smoking, should be taken in preterm infants.

Early manifestation of sleep problems in toddlers with Williams Syndrome using a mixed method longitudinal approach

Children with neurodevelopmental disorders commonly experience sleep problems. Williams Syndrome (WS), a rare genetic disorder characterised by a complex, uneven cognitive profile, is no exception. Compared with children with typical development (TD), school-aged children with WS experience significant sleep disruption: shorter sleep duration, more night wakings, greater bedtime resistance and excessive daytime tiredness. In children with TD, sleep problems impede optimal daytime functioning. In WS, this could compound existing difficulties. Few studies have examined sleep in very young children with WS and little is known about the early emergence of sleep problems in this population. To date, studies have been based on parent-report and no studies have objectively assessed sleep patterns using longitudinal approach in toddlers with WS. Thus, the current study sought to objectively explore sleep patterns in toddlers with WS. Parents of 38 children (13 WS, 25 TD) completed the Brief Infant Screening Questionnaire and the Medical and Demographics Questionnaire and sleep patterns were assessed using actigraphy. Data were collected longitudinally at ages 18, 24 and 30 months. Significant sleep disturbances were present in WS from 18 months old. Sleep duration, as measured by actigraphy, was significantly shorter in WS at all ages and, furthermore, parents of children with WS reported more night wakings, longer settling times and high levels of parental involvement. Crucially, whereas actigraphy showed developmental improvements in sleep quality in TD, no longitudinal changes were found in WS. Findings could be instrumental in working towards instigating appropriate, timely sleep management in this group, thus improving outcomes for children and their families.

A Review of Sleep Disturbances among Infants and Children with Neurodevelopmental Disorders

Sleep problems are common among children with neurodevelopmental disorders (NDDs). We review sleep disturbance in three major NDDs: autism spectrum disorder, Down syndrome, and fetal alcohol spectrum disorder (FASD). We review associations with functional impairment, discuss how patterns of sleep disturbance inform understanding of etiology, and theorize about mechanisms of impairment. Sleep disturbance is a transdiagnostic feature of NDDs. Caregivers report high rates of sleep problems, including difficulty falling or staying asleep. Polysomnography data reveal differences in sleep architecture and increased rates of sleep disorders. Sleep disturbance is associated with functional impairment and stress among families. Further research is needed to elucidate mechanisms of impairment and develop more effective interventions. Despite significant sleep disturbance in FASD, limited research is available.

Disentangling the Direction of Associations between Sleep and Temperament in Toddlers

OBJECTIVES/BACKGROUND

Although much research has investigated the associations between children's sleep and their temperament, the direction of these associations remains unclear, largely due to a lack of longitudinal studies with repeated assessments of both sleep and temperament. Aiming to clarify the temporal precedence of these two constructs, the current study investigated reciprocal associations between toddlers' sleep and temperament with a longitudinal design.

PARTICIPANTS

The sample consisted of 82 toddlers (39 girls) assessed twice.

METHODS

At both 2 (M = 25.23 months; SD = 1.11) and 3 years of age (M = 36.81 months; SD = 0.91), toddlers' sleep duration and quality were assessed using actigraphy and their temperament was reported by their mothers with the Toddler Behavior Assessment Questionnaire.

RESULTS

Shorter nighttime sleep duration (ß = - .28, p = .03) and lower sleep efficiency (ß = - .33, p = .01) at 2 years predicted more temperamental proneness to anger at 3 years, while greater temperamental social fear at 2 years was predictive of shorter 24-hour (ß = - .44, p = .02) and nighttime (ß = - .36, p = .04) sleep duration at 3 years. Associations between temperamental activity level and sleep variables were non-significant.

CONCLUSION

The direction of the associations between toddlers' sleep and their temperament may vary according to which dimension of temperament is considered. These findings should encourage practitioners to identify the beginning of the causal chain leading to sleep or temperamental difficulties so as to develop well-tailored intervention plans.

Racial Disparities in Sleep: Associations With Discrimination Among Ethnic/Racial Minority Adolescents

This study investigates the same-day associations between discrimination and sleep among 350 adolescents ages 13-15 (M = 14.29, SD = 0.65; Asian = 41%, Black = 22%, Latinx = 37%). Assessing sleep duration, sleep onset latency, and wake minutes after sleep onset using wrist actigraphy, Black adolescents slept 35 min less than Asian and 36 min less than Latinx youth. Black adolescents suffered the most wake minutes after sleep onset, followed by Latinx and Asian youth. Latinx youth reported the highest levels of sleep disturbance, whereas Asian youth reported the highest levels of daytime dysfunction. Daily discrimination was associated with lower levels of same-night sleep onset latency, more sleep disturbance, more next-day daytime dysfunction, and higher next-day daytime sleepiness.

What does a good night's sleep mean? Nonlinear relations between sleep and children's cognitive functioning and mental health

STUDY OBJECTIVES

We attempted to identify the duration and quality of sleep associated with the optimal child outcomes in key developmental domains including cognitive functioning, academic performance, and mental health. In doing so, we examined nonlinear associations between the sleep and developmental variables. Based on racial/ethnic disparities in children's sleep, we assessed this variable as a moderator of examined relations.

METHODS

Two hundred eighty-two children participated (Mage = 9.4 years, SD = .72; 52% boys; 65% white/European American, 35% black/African American). Sleep was examined with actigraphy for seven consecutive nights and with self-reports. Actigraphy-based sleep duration (minutes) and quality (efficiency), as well as self-reported sleep quality were derived. Children reported on their mental health and were administered cognitive performance tests. Mothers and teachers reported on children's mental health; teachers also reported on academic functioning. Schools provided academic achievement data.

RESULTS

Sleep duration had an accelerating nonlinear negative association with externalizing behaviors. Nonlinear associations were also detected between both actigraphy-derived and subjective reports of sleep quality and multiple developmental domains including academic functioning and mental health and the best functioning corresponded with the highest levels of sleep quality. Emphasizing the importance of individual differences, several examined associations were moderated by race/ethnicity.

CONCLUSIONS

Sleep duration and quality emerged as nonlinear predictors of multiple domains of child development. Findings illustrate that the benefits of longer and better-quality sleep did not taper off and that assessments of nonlinear relations may enhance understanding of the nature of associations between sleep and child functioning.

Sleep and Adiposity in Children From 2 to 6 Years of Age

OBJECTIVES

To compare sleep in young children at different obesity risks, which were based on parental weight, as well as to explore the longitudinal associations of sleep characteristics with adiposity.

METHODS

In total, 107 children from an obesity prevention project were included, of which 43 had normal-weight parents (low obesity risk) and 64 had overweight and/or obese parents (high obesity risk). Sleep was measured yearly from ages 2 to 6 years by using actigraphy. Five sleep characteristics, that of late sleep, long sleep latency, short sleep duration, low sleep efficiency, and irregular sleep onset, were defined and scored across ages, with a higher score indicating more frequent exposure. The outcome variables, also measured yearly, were BMI z score and waist circumference.

RESULTS

There was no difference in sleep patterns among children at different risks. Higher short sleep duration score was associated with a greater increase in BMI z score (0.12; 95% confidence interval [CI] 0.01 to 0.25) across ages. Independently of sleep duration, higher late sleep score was associated with greater increases in BMI z score (0.16; 95% CI 0.05 to 0.27) and waist circumference (0.60 cm; 95% CI 0.23 to 0.98). Moreover, compared with children at low risk and without habitual late sleep, children at high risk and with habitual late sleep had greater increases in BMI z score (0.93; 95% CI 0.40 to 1.45) and waist circumference (3.45 cm; 95% CI 1.78 to 5.12).

CONCLUSIONS

More frequent exposures to late sleep were associated with greater increases in adiposity measures from ages 2 to 6 years, particularly in children with obese parents.

Faded Bedtime Intervention for Delayed Sleep Onset in an Adolescent With Autism Spectrum Disorder

We report the case of an 18-year-old girl who had autism spectrum disorder (ASD) and demonstrated persistent delayed sleep onset after going to bed in her group home at a residential school. Intervention consisted of a faded bedtime in which her customary time to bed was extended later into the night, then gradually made earlier as she started falling asleep more rapidly over the course of many weeks. By conclusion of the study and at a 1-month follow-up, the girl was falling asleep in less than 30 min after going to bed and sleeping an average of 8.4 hr each night. Compared with previous research with children in inpatient and home environments, the study found positive effects from a faded bedtime intervention without additional procedures, targeted an adolescent with ASD, and was conducted by care providers in a novel residence setting.