Normal sleep patterns in infants and children: A systematic review of observational studies

Breastfeeding and Sleeping Patterns Among 6-12-Month-Old Infants in Norway

BACKGROUND

Parental behavior and infant sleep patterns can vary widely both within and between cultures and settings. Breastfeeding during the second half-year of infancy has been associated with frequent night waking, which is perceived as sleep problem among the Western societies. An understanding of sleeping patterns among breastfed infants during the second half-year of infancy is important in supporting continued breastfeeding.

OBJECTIVES

The study aimed to investigate the sleeping patterns among breastfed infants during second half-year of infancy.

METHODS

This is a cross-sectional study. Three hundred and forty-two mothers of 6-12 months old breastfed infants completed the questionnaires on socio-demographic factors, breastfeeding practices, and infant sleeping patterns, which were assessed by using the Brief Infant Sleep Questionnaire (BISQ). The Cox regression model was used to assess the factors that were associated with night sleep duration whereas demographic factors and breastfeeding practices that were associated with night waking frequency were investigated using the Poisson regression model.

RESULTS

On average, the breastfed infants slept for 11 h during the night and most infants were reported to have night waking (96.8%) and were breastfed at least once at night (93.5%). In the adjusted analyses, infants in the age group 9-12 months were less likely to sleep longer compared to infants in the 6-8 months age group [HR 1.52 95% CI (1.17, 1.98)]. A one-hour increase in daytime sleep and in night wakefulness increased the likelihood of waking up at night by 19% and 24%, respectively. Infants who had been vaccinated within the last 7 days and infants who were breastfed to sleep were more likely to have a shorter nighttime sleep duration. Nighttime breastfeeding frequency was significantly associated with a 17% increase in the likelihood of night waking [IRR 1.17 95% CI (1.13, 1.22)]. Infants who slept on their parents' bed were 1.28 times more likely to wake up at night compared to infants who slept in a separate room [IRR 1.28 95% CI (1.05, 1.59)]. Infants of parents who reported that their infants' sleep was not a problem were 34% less likely to wake up compared to infants of parents who reported that their infants' sleep was a problem [IRR 0.66 95% CI (0.49, 0.87)]. CONCLUSIONS FOR PRACTICE: Frequent night waking, bed sharing and night breastfeeding were common among 6-12 months old breastfed infants. Frequent night breastfeeding may lengthen an infant's nighttime sleep duration. The study findings indicate that adequate information and support should be given to breastfeeding mothers in relation to the sleeping pattern of breastfed infants in order to promote continued breastfeeding practices.

From co-regulation to self-regulation: Maternal soothing strategies and self-efficacy in relation to maternal reports of infant regulation at 3 and 7 months

This study, conducted in Germany, examines the role of maternal soothing strategies to explain the association of maternal self-efficacy with infant regulation (crying and sleeping behavior). Questionnaire data of 150 mothers, living in Germany, with mixed ethnic and educational backgrounds were collected when infants were 3 and 7 months old. Two types of maternal soothing strategies were distinguished: close soothing, involving close physical and emotional contact, and distant soothing, involving physical and emotional distancing from the infant. A cross-sectional SEM at 3 months indicated that maternal self-efficacy is associated with reported infant regulation through distant soothing strategies. Low maternal self-efficacy was associated with frequent maternal use of distant soothing, which in turn was related to reported infant regulation problems, that is, non-soothability and greater crying frequency. Frequent use of close soothing was associated with reported infant sleeping behavior, that is, frequent night-time awakenings. A longitudinal SEM further indicated that the effects of close soothing persisted at least until the infants' age of 7 months. The study showed how low maternal self-efficacy, increased use of distant soothing, and reported early infant regulation problems are intertwined and that, due to their persisting positive effect on infant soothability, close soothing better supports infant development.

Sleep characteristics, early spontaneous movements, and developmental functioning in preterm infants in the early postnatal period

OBJECTIVE

This study aimed to investigate the following: (i) sleep characteristics in preterm infants at 9-20 weeks of corrected age, and (ii) differences in early spontaneous movements and developmental functioning results between the groups based on some sleep characteristics.

METHODS

Seventy-four preterm infants (36 female) were included. Sleep characteristics were assessed according to the Brief Infant Sleep Questionnaire (BISQ). The infants were divided into two groups based on total sleep duration: less than 12 h (38 infants), and 12 h and more (36 infants). Video recordings were made for the General Movements Assessment (GMA) and evaluated using the Motor Optimality Score for 3- to 5-Month-Old-Infants-Revised (MOS). Cognitive, language, and motor development were assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III).

RESULTS

The total sleep duration of all preterm infants (mean ± SD) was 11.8 ± 3.3 h. Infants who had absent fidgety movements slept less than 12 h, and fidgety movements differed between the groups (p = 0.012). Infants who slept 12 h or more had significantly higher MOS (p = 0.041), cognitive (p = 0.002), language (p < 0.001), and motor (p = 0.002) development results. Infants who snored had lower MOS (p = 0.001), cognitive (p = 0.004), language (p = 0.002), and motor (p = 0.001) development results. Infants with fewer than three nocturnal awakenings had significantly higher Bayley-III cognitive (p = 0.007), language (p = 0.032), and motor (p = 0.005) domain results. Prone and supine sleeping positions showed higher motor domain results than lateral positions (p = 0.001).

CONCLUSIONS

Sleep in preterm infants might be a key factor in early developmental functioning processes and nervous system integrity. Even in the first months of life, there are substantial differences in cognitive, language, and motor development in association with sleep characteristics.

Contributions of the light environment and co-sleeping to sleep consolidation into nighttime in early infants: A pilot study

BACKGROUND

Sleep consolidation into nighttime is considered the primary goal of sleep development in early infants. However, factors contributing to sleep consolidation into nighttime remain unclear.

AIM

To clarify the influences of the light environment and nighttime co-sleeping on sleep consolidation into nighttime in early infants.

STUDY DESIGN

Cross-sectional study.

SUBJECTS AND METHODS

Sleep-wake time and light stimulation were measured in infants for 4 consecutive days using actigraphy. The infants' mothers were asked to complete a sleep events diary and a questionnaire about childcare, including "co-sleeping", defined as when the infant and mother slept on the same surface throughout the night.

OUTCOME MEASURES

The data were analyzed with a focus on daytime and nighttime sleep parameters.

RESULTS

Daytime light stimulation reduced daytime "active sleep", tended to reduce daytime sleep, and increased daytime waking. Nighttime light stimulation reduced nighttime "quiet sleep" and nighttime sleep and increased nighttime waking. Co-sleeping reduced nighttime waking, and, as a result, nighttime sleep time and sleep efficiency increased. Co-sleeping reduced daytime sleep and tended to increase daytime waking. Consequently, co-sleeping tended to increase the ratio of nighttime sleep to daytime sleep.

CONCLUSIONS

The present findings suggest that an appropriate light environment promotes daytime waking and nighttime sleep in early infants, but it does not contribute to sleep consolidation into nighttime by itself. On the other hand, co-sleeping may promote sleep consolidation into nighttime. Therefore, further methods for safe co-sleeping need to be established while avoiding risk factors for sudden unexpected death in infancy/sudden infant death syndrome.

The effect of a neonatal sleep intervention on maternal postpartum hypertension: a randomized trial

BACKGROUND

In nonpregnant adults, poor sleep is associated with higher blood pressure. Poor sleep is common in the postpartum period and is often attributed to infant caretaking needs. However, its effects on cardiovascular health in individuals with a hypertensive disorder of pregnancy are unknown.

OBJECTIVE

This study aimed to determine the effect of a neonatal sleep intervention on maternal postpartum blood pressure in individuals with a hypertensive disorder of pregnancy.

STUDY DESIGN

In this single-institution pilot randomized controlled trial from July 2021 to March 2022, 110 individuals with a hypertensive disorder of pregnancy were randomized to receive a neonatal sleep intervention (SNOO responsive bassinet) plus usual care of safe sleep education (n=54) or usual care alone (n=56). Remote follow-up visits were conducted at 1 week, 6 weeks, and 4 months after delivery and involved blood pressure and weights, sleep and mood questionnaires, and self-reported infant and maternal sleep logs. Based on institutional data, the sample size had 80% power to detect a 4.5-mm Hg difference in the primary outcome of mean arterial pressure at 6 weeks after delivery.

RESULTS

Baseline characteristics were similar between the arms. At 1 week after delivery, the intervention arm had lower mean arterial pressure and less antihypertensive medication use than the control arm (99±10 vs 103±7 mm Hg [P=.04] and 23% vs 35% [P=.15], respectively). At 6 weeks after delivery, mean arterial pressure was similar between arms (93±8 vs 94±8 mm Hg; P=.54), but there was a lower rate of antihypertensive use in the intervention arm (15% vs 26%; P=.19). Scores from maternal sleep and mood questionnaires at 6 weeks after delivery and self-reported infant and maternal sleep duration at 6 weeks and 4 months after delivery were similar between arms (P>.05).

CONCLUSION

The SNOO responsive bassinet as a neonatal sleep intervention did not result in improved mean arterial pressure at 6 weeks after delivery after hypertensive disorders of pregnancy.

Orexin Receptor Antagonism: Normalizing Sleep Architecture in Old Age and Disease

Sleep is essential for human well-being, yet the quality and quantity of sleep reduce as age advances. Older persons (>65 years old) are more at risk of disorders accompanied and/or exacerbated by poor sleep. Furthermore, evidence supports a bidirectional relationship between disrupted sleep and Alzheimer's disease (AD) or related dementias. Orexin/hypocretin neuropeptides stabilize wakefulness, and several orexin receptor antagonists (ORAs) are approved for the treatment of insomnia in adults. Dysregulation of the orexin system occurs in aging and AD, positioning ORAs as advantageous for these populations. Indeed, several clinical studies indicate that ORAs are efficacious hypnotics in older persons and dementia patients and, as in adults, are generally well tolerated. ORAs are likely to be more effective when administered early in sleep/wake dysregulation to reestablish good sleep/wake-related behaviors and reduce the accumulation of dementia-associated proteinopathic substrates. Improving sleep in aging and dementia represents a tremendous opportunity to benefit patients, caregivers, and health systems.

Sleep duration in preschool age and later behavioral and cognitive outcomes: an individual participant data meta-analysis in five European cohorts

Short sleep duration has been linked to adverse behavioral and cognitive outcomes in schoolchildren, but few studies examined this relation in preschoolers. We aimed to investigate the association between parent-reported sleep duration at 3.5 years and behavioral and cognitive outcomes at 5 years in European children. We used harmonized data from five cohorts of the European Union Child Cohort Network: ALSPAC, SWS (UK); EDEN, ELFE (France); INMA (Spain). Associations were estimated through DataSHIELD using adjusted generalized linear regression models fitted separately for each cohort and pooled with random-effects meta-analysis. Behavior was measured with the Strengths and Difficulties Questionnaire. Language and non-verbal intelligence were assessed by the Wechsler Preschool and Primary Scale of Intelligence or the McCarthy Scales of Children's Abilities. Behavioral and cognitive analyses included 11,920 and 2981 children, respectively (34.0%/13.4% of the original sample). In meta-analysis, longer mean sleep duration per day at 3.5 years was associated with lower mean internalizing and externalizing behavior percentile scores at 5 years (adjusted mean difference: - 1.27, 95% CI [- 2.22, - 0.32] / - 2.39, 95% CI [- 3.04, - 1.75]). Sleep duration and language or non-verbal intelligence showed trends of inverse associations, however, with imprecise estimates (adjusted mean difference: - 0.28, 95% CI [- 0.83, 0.27] / - 0.42, 95% CI [- 0.99, 0.15]). This individual participant data meta-analysis suggests that longer sleep duration in preschool age may be important for children's later behavior and highlight the need for larger samples for robust analyses of cognitive outcomes. Findings could be influenced by confounding or reverse causality and require replication.

Mapping neurodevelopment with sleep macro- and micro-architecture across multiple pediatric populations

Profiles of sleep duration and timing and corresponding electroencephalographic activity reflect brain changes that support cognitive and behavioral maturation and may provide practical markers for tracking typical and atypical neurodevelopment. To build and evaluate a sleep-based, quantitative metric of brain maturation, we used whole-night polysomnography data, initially from two large National Sleep Research Resource samples, spanning childhood and adolescence (total N = 4,013, aged 2.5 to 17.5 years): the Childhood Adenotonsillectomy Trial (CHAT), a research study of children with snoring without neurodevelopmental delay, and Nationwide Children's Hospital (NCH) Sleep Databank, a pediatric sleep clinic cohort. Among children without neurodevelopmental disorders (NDD), sleep metrics derived from the electroencephalogram (EEG) displayed robust age-related changes consistently across datasets. During non-rapid eye movement (NREM) sleep, spindles and slow oscillations further exhibited characteristic developmental patterns, with respect to their rate of occurrence, temporal coupling and morphology. Based on these metrics in NCH, we constructed a model to predict an individual's chronological age. The model performed with high accuracy (r = 0.93 in the held-out NCH sample and r = 0.85 in a second independent replication sample - the Pediatric Adenotonsillectomy Trial for Snoring (PATS)). EEG-based age predictions reflected clinically meaningful neurodevelopmental differences; for example, children with NDD showed greater variability in predicted age, and children with Down syndrome or intellectual disability had significantly younger brain age predictions (respectively, 2.1 and 0.8 years less than their chronological age) compared to age-matched non-NDD children. Overall, our results indicate that sleep architectureoffers a sensitive window for characterizing brain maturation, suggesting the potential for scalable, objective sleep-based biomarkers to measure neurodevelopment.

Efficient, continual, and generalized learning in the brain - neural mechanism of Mental Schema 2.0

There has been tremendous progress in artificial neural networks (ANNs) over the past decade; however, the gap between ANNs and the biological brain as a learning device remains large. With the goal of closing this gap, this paper reviews learning mechanisms in the brain by focusing on three important issues in ANN research: efficiency, continuity, and generalization. We first discuss the method by which the brain utilizes a variety of self-organizing mechanisms to maximize learning efficiency, with a focus on the role of spontaneous activity of the brain in shaping synaptic connections to facilitate spatiotemporal learning and numerical processing. Then, we examined the neuronal mechanisms that enable lifelong continual learning, with a focus on memory replay during sleep and its implementation in brain-inspired ANNs. Finally, we explored the method by which the brain generalizes learned knowledge in new situations, particularly from the mathematical generalization perspective of topology. Besides a systematic comparison in learning mechanisms between the brain and ANNs, we propose "Mental Schema 2.0," a new computational property underlying the brain's unique learning ability that can be implemented in ANNs.

More frequent naps are associated with lower cognitive development in a cohort of 8-38-month-old children, during the Covid-19 pandemic

Background

How often a child naps, during infancy, is believed to reflect both intrinsic factors, that is, the need of an immature brain to consolidate information soon after it is acquired, and environmental factors. Difficulty accounting for important environmental factors that interfere with a child's sleep needs (e.g., attending daycare) has clouded our ability to understand the role of intrinsic drivers of napping frequency.

Methods

Here we investigate sleep patterns in association with two measures of cognitive ability, vocabulary size, measured with the Oxford-Communicative Development Inventory (N = 298) and cognitive executive functions (EF), measured with the Early EF Questionnaire (N = 463), in a cohort of 8-38-month-olds. Importantly, because of the social distancing measures imposed during the Covid-19 Spring 2020 lockdown, in the UK, measures of sleep were taken when children did not access daycare settings.

Results

We find that children with more frequent but shorter naps than expected for their age had lower concurrent receptive vocabularies, lower cognitive EF and a slower increase in expressive vocabulary from spring to winter 2020, when age, sex, and SES were accounted for. The negative association between vocabulary and frequency of naps became stronger with age.

Conclusions

These findings suggest that the structure of daytime sleep is an indicator of cognitive development and highlight the importance of considering environmental perturbations and age when investigating developmental correlates of sleep.

Sociodemographic, temporal and bedtime routine correlates of sleep timing and duration in South Asian and white children: A Born in Bradford study

Objective

The study aimed to examine sociodemographic, temporal and bedtime routine correlates of parent-reported sleep duration and timing in a biethnic sample of 18 month and 36 month old children from a disadvantaged location.

Methods

Between October 2010 and September 2012, parents completed a bespoke three day sleep diary when their child was approximately 18 months (n = 276) and 36 months of age (n = 262) (45.1% South Asian; 54.9% white). Parents reported their child's overnight sleep duration (h/day), the time their child fell asleep, their wake time and their child's bedtime and napping routines. Data were available at both time points for 135 children.

Results

In line with previous literature, South Asian children had shorter overnight sleep duration and later sleep and wake times than white children. In both ethnic groups, children slept and woke up later on weekends, and children went to bed earlier and slept longer in winter. In white children only, napping duration was associated with overnight sleep period. No significant associations were found between napping frequency and overnight sleep duration. Based on parent-reported data, children who consistently adhered to regular bedtimes and had set times for sleeping tended to go to sleep earlier, wake earlier and have longer overnight sleep.

Conclusions

The data showed parent-reported variation in sleep patterns between two ethnic groups within a single geographical and deprived area. It is important that researchers, clinicians and early years workers are considerate of cultural norms in sleep practices.

Sleep hygiene a neglected paediatric identity - A cross-sectional study

Background

Sleep is the physiological need of any human being; its role in paediatric mental and physical development is irreplaceable. However, in recent days, the rising trend of childhood obesity makes it essential to assess the sleep hygiene of the children to know if there is any adjacent association.

Objectives

1. To estimate the prevalence of poor sleep quality using Sleep Hygiene Index Scoring. 2. To determine the association of sleep quality with academic performance and body mass index among the school children.

Materials and Methods

The present cross-sectional study was conducted among 322 children aged between 7 and 12 years attending paediatric OPD of a private tertiary care hospital, Puducherry. Using Sleep Hygeine Index scoring with the cut off 16, prevalence of poor sleep quality was assessed and its association with BMI and academic performance was determined. Frequency, proportion, and Chi-square test were used for analysis; P value < 0.05 was considered statistically significant.

Results

The mean age of the participants was 8.8 ± 2 years, and most of them were boys. Around 53% of the children had poor quality of sleep, and there was a positive association between poor sleep quality with obesity (P value: 0.0003) and unfavourable academic performance (P value: 0.00001).

Conclusion

Sleep hygiene importance should be taught to the parents and periodical assessment helps in predicting the neglected reason for obesity and poor academic performance, which could be managed easily with small lifestyle changes.

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.

From early birds to night owls: a longitudinal study of actigraphy-assessed sleep trajectories during the transition from pre- to early adolescence

STUDY OBJECTIVES

Pre- and early adolescence are believed to constitute periods of important age-related changes in sleep. However, much of the research on these presumed developmental changes has used cross-sectional data or subjective measures of sleep, limiting the quality of the evidence. In addition, little is known about the development of certain features of the sleep-wake cycle pertaining to regularity (e.g. weekend-weekday differences and intra-individual variability) or circadian rhythms (e.g. sleep midpoint).

METHODS

This study examined the sleep trajectories of 128 typically developing youth (69 girls) from ages 8 to 12 years on four sleep characteristics: sleep onset, sleep offset, total sleep time (TST), and sleep midpoint. For each of these characteristics, actigraphy-derived estimates of typical (i.e. mean) sleep and sleep regularity were obtained at each time point. Multilevel growth curves were modeled.

RESULTS

Overall, the sleep-wake cycle significantly changed between 8 and 12 years. Mean sleep onset, offset and midpoint exhibited an ascending curvilinear growth pattern that shifted later with age, while mean TST decreased linearly. Weekend-weekday differences (social jetlag) for sleep offset and midpoint became more pronounced each year. Weekday TST was longer than weekend TST, though this difference became smaller over time. Finally, intra-individual variability increased over time for all sleep characteristics, with variability in TST ascending curvilinearly. Important between-person and sex differences were also observed.

CONCLUSION

This study reveals the marked changes that occur in the sleep of typically developing pre- and early adolescents. We discuss the potential implications of these trajectories.

Rest-activity rhythms across the lifespan: cross-sectional findings from the US representative National Health and Nutrition Examination Survey

STUDY OBJECTIVES

Rest-activity rhythms (RAR) may mark development, aging, and physical and mental health. Understanding how they differ between people may inform intervention and health promotion efforts. However, RAR characteristics across the lifespan have not been well-studied. Therefore, we investigated the association between RAR measures with demographic and lifestyle factors in a US nationally representative study.

METHODS

RAR metrics of interdaily stability (IS), intradaily variability (IV), relative amplitude (RA), and mean amplitude and timing of high (M10) and low (L5) activity were derived from 2011 to 2012 and 2013 to 2014 National Health and Nutrition Examination Survey (NHANES) actigraphy data. Population-weighted linear and logistic regression models were fit to examine the associations of age, gender, smoking, alcohol, season, body mass index (BMI), income-to-poverty ratio, and race/ethnicity with RAR. Significance was based on a false-discovery rate-corrected P-value of <0.05.

RESULTS

Among n = 12 526 NHANES participants (3-≥80 years), IS (higher = greater day-to-day regularity) and RA (higher = greater rhythm strength) generally decreased with age and were lower among males, whereas IV (higher = greater rhythm fragmentation) increased with age (p < 0.05). Dynamic changes in RAR trajectories were observed during childhood and adolescence. Income, BMI, smoking, and alcohol use were associated with RAR metrics, as well as season among children and teenagers (p < 0.05). RAR also differed by race/ethnicity (p < 0.05), with trajectories initially diverging in childhood and continuing into adulthood.

CONCLUSIONS

RAR differed by demographic and health-related factors, representing possible windows for public health intervention and sleep health promotion. RAR differences by race/ethnicity begin in childhood, are evident in early adolescence, and persist throughout adulthood.

Maternal Prenatal Depressive Symptoms and Infant Sleep Problems: The Role of Infant Temperament and Sex

OBJECTIVES

We aimed to analyze whether (1) infant temperament mediates the impact of maternal prenatal depressive symptoms on infant sleep problems and (2) the mediation role of infant temperament was moderated by the infant's sex.

METHODS

The sample was comprised of 172 mother-infant dyads. Mothers completed self-reported measures of prenatal and postnatal depressive symptoms, infant temperament (negative affectivity, surgency/extraversion, and orienting regulation), and sleep problems.

RESULTS

While controlling for maternal postnatal depressive symptoms, our results revealed that (1) infant negative affectivity at two weeks partially mediated the impact of maternal prenatal depressive symptoms on sleep anxiety at six months, and (2) this mediation is independent of the infant's sex.

CONCLUSIONS

Our findings provided evidence that negative affectivity can be an early specific marker of sleep anxiety and can partially explain the negative impact of maternal prenatal depressive symptoms on further sleep problems in the infant.

An observational pilot study of sleep disruption and delirium in critically ill children

BACKGROUND

Sleep disruption is frequently observed in children with delirium in the pediatric intensive care unit (PICU).

OBJECTIVES

This observational pilot study explores relationships among modifiable characteristics of the PICU environment (i.e., light, sound, clinician caregiving patterns), sleep disruption, and delirium.

METHODS

Ten children, 1 to 4 years old, were recruited within 48 h of PICU admission and followed until discharge. A light meter, dosimeter, and video camera were placed at bedside to measure PICU environmental exposures. Sleep was measured via actigraphy. Twice daily delirium screening was conducted. Descriptive statistics were used to describe the PICU environment, sleep, and delirium experienced by children. Bivariate analyses were performed to determine relationships among variables.

RESULTS

Average participant age was 21 (SD = 9.6) months. Eight (80%) were admitted for respiratory failure. Median PICU length of stay was 36.7 (IQR[29.6, 51.5]) hours, which limited data collection duration. Delirium prevalence was 60% (n = 6). Children experienced low daytime light levels (x¯ = 112.8 lux, SD = 145.5) and frequent peaks (x¯ = 1.9/hr, SD = 0.5) of excessive sound (i.e., ≥ 45 A-weighted decibels). Clinician caregiving episodes were frequent (x¯ = 4.5/hr, SD = 2.6). Children experienced 7.3 (SD = 2.1) awakenings per hour of sleep and a median sleep episode duration of 1.4 (IQR[0.6, 2.3]) hours. On average, children with delirium experienced 1.1 more awakenings per sleep hour and 42 fewer minutes of sleep per sleep episode during the night shift. Increased clinician care frequency and duration were associated with worse sleep quality and delirium.

CONCLUSIONS

Study results will inform future, large-scale research and nurse-driven sleep promotion interventions.

The unified theory of sleep: Eukaryotes endosymbiotic relationship with mitochondria and REM the push-back response for awakening

The Unified Theory suggests that sleep is a process that developed in eukaryotic animals from a relationship with an endosymbiotic bacterium. Over evolutionary time the bacterium evolved into the modern mitochondrion that continues to exert an effect on sleep patterns, e.g. the bacterium Wolbachia establishes an endosymbiotic relationship with Drosophila and many other species of insects and is able to change the host's behaviour by making it sleep. The hypothesis is supported by other host-parasite relationships, e.g., Trypanosoma brucei which causes day-time sleepiness and night-time insomnia in humans and cattle. For eukaryotes such as Monocercomonoids that don't contain mitochondria we find no evidence of them sleeping. Mitochondria produce the neurotransmitter gamma aminobutyric acid (GABA), and ornithine a precursor of the neurotransmitter GABA, together with substances such as 3,4dihydroxy phenylalanine (DOPA) a precursor for the neurotransmitter dopamine: These substances have been shown to affect the sleep/wake cycles in animals such as Drosophilia and Hydra. Eukaryote animals have traded the very positive side of having mitochondria providing aerobic respiration for them with the negative side of having to sleep. NREM (Quiet sleep) is the process endosymbionts have imposed upon their host eukaryotes and REM (Active sleep) is the push-back adaptation of eukaryotes with brains, returning to wakefulness.

Does the feeding method affect the quality of infant and maternal sleep? A systematic review

Breastfeeding brings many benefits to both mother and infant. Although, many women stop breastfeeding their infants too soon. The perceived association between breastfeeding and sleep may influence their decision to terminate breastfeeding. In our systematic review, we focused on mapping the relationship between infant feeding method and total sleep time (TST), number of nocturnal awakenings, awakenings after sleep onset (WASO) of mothers and infants and sleep quality of mothers. We searched four databases according to selected keywords and inclusion criteria - articles published in peer-reviewed journals between 2012 and 2022; English language; a sample consisting of mothers, infants, or both (without psychiatric and health problems); a comparison of the sleep quality of breastfed and formula-fed children or breastfeeding and formula-fed mothers. We read 260 full texts of selected articles. A total of 35 articles were included in this review. Due to significant heterogeneity, meta-analysis was not possible to accomplish. The results are processed according to narrative synthesis. Most studies agree that breastfed infants wake up more often at night. Total sleep time and time spent awake during the night (WASO) did not differ between breastfed and non-breastfed infants. We observed identical results in sleep variables among mothers. Additionally, there was no difference in maternal sleep quality. The synthesis revealed that the results may have differed due to using subjective, objective methods or the infant's age. It is important to remember that night waking is a more complex concept. Infants wake for many reasons, not just due to breastfeeding. The narrative synthesis indicated that the chosen study design, measurement method, the variables, and the infant's age could influence outcomes. In addition, other variables appeared that may affect the entire process. Therefore, we recommend that attention be paid to this in future studies.

Postpartum stress in the first 6 months after delivery: a longitudinal study in Nantong, China

OBJECTIVES

The objective is to to explore the longitudinal change trajectories of postpartum stress and its related factors.

DESIGN

A longitudinal study with follow-ups from 42 days to 6 months after delivery.

SETTINGS AND PARTICIPANTS

A total of 406 postpartum women were recruited at baseline (42 days after delivery) from 6 hospitals in Nantong, Jiangsu Province, China, and followed up at 3 and 6 months. After the follow-ups, 358 postpartum women were retained for further analysis.

METHODS

Postpartum stress was evaluated using the Maternal Postpartum Stress Scale (MPSS) at baseline (42 days) and 3 and 6 months after delivery. MPSS has three dimensions, such as: personal needs and fatigue, infant nurturing and body changes and sexuality. Postpartum depression and anxiety were measured using the Edinburgh Postnatal Depression Scale and the short-form Depression, Anxiety and Stress Scale, respectively. The MPSS scores were normalised using a rank-based inverse normal transformation.

RESULTS

Postpartum stress decreased significantly after 3 months, and postpartum stress reduced further after 6 months. Additionally, the scores for all three dimensions reduced after 6 months, while infant nurturing reduced after both 3 and 6 months. Older age (β=0.028, p=0.049), higher education level (β=0.153, p=0.005) and higher body mass index (BMI) (β=0.027, p=0.008) of the postpartum women were significantly associated with higher postpartum stress levels in corresponding dimensions at 42 days. Older age was also associated with higher postpartum stress at 3 (β=0.030, p=0.033) and 6 months (β=0.050, p<0.001) in the dimension of personal needs and fatigue. Postpartum stress levels were significantly higher in women with depression or anxiety symptoms.

CONCLUSIONS

Postpartum stress continuously declined from 42 days to 6 months after delivery. Postpartum women with older age, higher education levels, higher BMI and anxiety or depression symptoms should be the target population for early intervention.

A preliminary study on the performance of the Nanit auto-videosomnography scoring system against observed video scoring and actigraphy to estimate sleep-wake states in infants

GOAL AND AIMS

To examine the performance of the Nanit auto-videosomnography scoring system as a measure of sleep-wake states in infants compared to observed video scoring and actigraphy.

FOCUS TECHNOLOGY

Nanit's auto-videosomnography scoring system.

REFERENCE

Observed video scoring and actigraphy.

SAMPLE

Sixteen U.S. infants (age: 4-8 months).

DESIGN

Infants' sleep was assessed with the Nanit camera and actigraphy (micromotion logger sleep watch). Fifty nights were included in the analyses. Nanit's videos were processed via a computer vision algorithm and were scored by trained observers. Actigraphic data were scored with the validated Sadeh algorithm.

CORE ANALYTICS

Bland-Altman plots and epoch-by-epoch analyses (sensitivity, specificity, and total accuracy).

ADDITIONAL ANALYTICS

Specificity values for each night separately.

CORE OUTCOMES

Nanit estimates of sleep minute were not significantly different from observed sleep minute, but Nanit overestimated sleep minute relative to actigraphy by 17 minutes. Nanit overestimated wake minutes (wake after sleep onset by 5.3 minutes relative to observed scoring and underestimated wake after sleep onset by 19.1 minutes relative to actigraphy. The epoch-by-epoch analyses revealed that Nanit reached 97.8% sensitivity in classifying sleep and 60.4% specificity in classifying wake compared to observed scoring. The rates compared to actigraphy were 99.3% for sensitivity and 51.7% for specificity.

IMPORTANT ADDITIONAL OUTCOMES

Specificity values were lower for infants with lower wake after sleep onset.

CORE CONCLUSION

This preliminary study suggests that Nanit is highly accurate in detecting infant sleep compared to observed scoring and actigraphy. Specificity values are within the range of those reported previously for actigraphy devices that are commonly used in pediatric sleep research.

Effects of psychosocial sleep interventions on improving infant sleep and maternal sleep and mood: A systematic review and meta-analysis

Infant sleep problems are prevalent and have a negative impact on infant growth and development, maternal sleep, and maternal mood. The effects of psychosocial sleep interventions on infant sleep and maternal sleep and mood are unclear. This study aimed to systematically evaluate the effects of psychosocial sleep interventions on improving infant sleep, including nocturnal total sleep time, daytime total sleep, total sleep time, night wakings, and maternal sleep and mood problems (ie, depression and fatigue). We searched PubMed, Web of Science, Cochrane Library, Embase, EBSCO, OpenGrey, DeepBlue, China National Knowledge Infrastructure, and Wanfang databases. We focused on randomized controlled trials examining the effectiveness of psychosocial sleep interventions on infant sleep. The study was preregistered at the International Prospective Register of Systematic Reviews (CRD42022301654). Thirteen studies from 5889 articles were included in the review, which found that psychosocial sleep interventions improved infant nocturnal total sleep time (0.28 [0.04-0.52], p < 0.05, I2 = 83.9%) and maternal depression (-0.10 [-0.28 to -0.08], p < 0.05, I2 = 8.7%). To test and explore heterogeneity, we used the I2 statistic, influence analysis, subgroup analyses, and subgroup meta-analyses. Funnel plots and Egger's tests revealed no evidence of publication bias. Psychosocial sleep interventions improved infant nocturnal total sleep time and maternal depression. Future research should include more randomized controlled trials examining the effect of psychosocial sleep interventions on the improvement of maternal sleep and fatigue.

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.

Obesogenic sleep patterns among Chinese preschool children: A latent profile and transition analysis of the association sleep patterns and obesity risk

OBJECTIVE

This paper utilized a person-centered approach to examine whether sleep patterns on school and free days are associated with obesity risk in preschool children aged 3-6 years.

METHODS

The cross-sectional analysis included 204 children from the Wuhan Healthy Start Project with valid sleep data in at least four consecutive days gathered via Actigraph GT3X+. Based on three domains of sleep duration, sleep onset, and sleep offset, we used latent profile analysis to identify distinct sleep patterns on school and free days separately. Additionally, we conducted latent transition analysis to explore the probabilities of sleep patterns transitions between school and free days. The multivariate logistic regression model investigated the associations of sleep patterns with overweight/obesity (OWO) (BMI ≥ age- and sex-specific 85th percentile) and abdominal obesity (AO) (WC ≥ age- and sex-specific 75th percentile).

RESULTS

Two sleep patterns were identified for school days: "EL-sc" (early-to-sleep/longer-duration) (n = 119; 58.3%) and "LS-sc" (late-to-sleep/shorter-duration) (n = 85; 41.7%). Similarly, "LES-fr" (late-to-sleep/early-to-wake/shorter-duration) (n = 118; 57.8%) and "ELL-fr" (early-to-sleep/late-to-wake/longer-duration) (n = 86; 42.2%) patterns were identified for free days. LTA categorized the participants into four distinct transition groups, i.e., "EL-sc→ELL-fr" (32.9%), "EL-sc→LES-fr" (24.0%), "LS-sc→LES-fr" (33.8%), and "LS-sc→ELL-fr" (9.3%). Compared with the "ELsc→ELL-fr", the "LS-sc→LES-fr" had a higher risk of OWO (AOR 4.76; 95% CI: 1.39-20.33) and AO (AOR, 2.78; 95% CI, 1.21-6.62), respectively. Neither "EL-sc→LES-fr" (AOR, 1.11; 95% CI, 0.14-6.67) nor "LS-sc→ELL-fr" (AOR, 0.74; 95% CI, 0.03-6.14) was significantly associated with OWO. Likewise, no significant association was observed for "EL-sc→LES-fr" (AOR, 0.96; 95% CI, 0.35-2.62) and "LS-sc→ELL-fr" (AOR, 0.56; 95% CI, 0.11-2.18) with AO.

CONCLUSIONS

"LS-sc→LES-fr" pattern is significantly associated with an increased risk of general and abdominal obesity, indicating its obesogenic nature. Furthermore, although not statistically associated with obesity outcomes, "LS-sc→ELL-fr" and "EL-sc→LES-fr" patterns exhibit a semi-obesogenic characteristic. In addition, we identified a concerning trend that preschool children are at risk of transitioning to and persisting in sleep patterns characterized by delayed and shorter sleep. These findings underscore the importance of implementing interventions and strategies to address sleep patterns as a crucial step to minimize the risk of obesity.

Promoting healthy sleep in Chinese kindergarteners through a family-based intervention: protocol of the "Healthy Sleep" randomised controlled trial

BACKGROUND

Sleep is instrumental for growth and development in children, making it critical to establish healthy sleep habits from the earliest years of life. Many kindergarteners (3-6 years) in China have inadequate and poor sleep, necessitating targeted interventions. This research protocol details the "Healthy Sleep" intervention that was designed to promote healthy sleep among kindergarteners in China.

METHODS

The "Healthy Sleep" intervention will be family-based and will support parents as change agents. The development of the intervention is based on evidence regarding correlates of sleep in young children and guided by Bandura's social cognitive theory. A 12-month randomised controlled trial will be conducted to examine the efficacy of the intervention for promoting healthy sleep in Chinese kindergarteners and the intervention's effects on child development outcomes. A targeted sample of 160 kindergarteners and their parents will be recruited through social media. The intervention group (n = 80) will receive monthly webinars for one year that include multiple intervention components - including educational training, goal setting and planning, as well as follow-up support sessions. The control group (n = 80) will receive videos of the recorded educational sessions after the study end. For primary outcomes, child sleep behaviours will be examined using the Child Sleep Health Questionnaire. For secondary outcomes, communication, fine motor, gross motor, personal-social, and problem-solving development will be examined using the Ages and Stages Questionnaire; executive functions will be examined using the Head, Toes, Knees, and Shoulders Revised tasks. Potential intervention mediators and covariates will be measured using a parental questionnaire. Mixed models will be conducted.

DISCUSSION

This intervention targets sleep behaviours among kindergarteners in China. It has the potential to inform programs to support parents in helping their child establish healthy sleep habits from the earliest years of life. The study will provide high-quality experimental evidence on sleep behaviours in relation to development outcomes in kindergarteners. This evidence will inform family-based strategies to optimise early childhood development and inform national and international updates of the sleep recommendations for young children.

TRIAL REGISTRATION

The trial was registered prospectively at Chinese Clinical Trial Registry (ID: ChiCTR2300072105) on 2 June 2023.

Qualitative study of the association between psychosocial health and physical activity/sleep quality in toddlers

Physical activity and sleep are important factors of mental and physical health in children, with some reports indicating that their effects can persist into adulthood. However, there is limited research on the qualitative aspects of physical activity and sleep in preschool children, particularly in those aged < 3 years. Therefore, to elucidate the association between psychosocial health and physical activity/sleep in early childhood in terms of qualitative aspects, we conducted a retrospective cohort study in 2985 3-year-old children (37.2 ± 0.75 months) in Shanghai, China. An analysis using structural equation modeling indicated that current physical activity had a direct and moderate impact on current psychosocial health evaluated using the Strength and Difficulties Questionnaire. In particular, past physical activity had an indirect and mild effect on current psychosocial health via current physical activity in girls. However, regardless of sex, past sleep quality had slight impact on current psychosocial health, not only indirectly via current sleep quality, but also directly. These findings highlight the importance of considering the qualitative aspects of physical activity and sleep quality as significant factors influencing the current and future psychosocial health of children, even at a very early age (< 3 years).

The developmental trajectory of sleep in children with Smith-Magenis syndrome compared to typically developing peers: a 3-year follow-up study

Study Objectives

To determine the trajectory of: (i) objective sleep parameters and (ii) caregiver-reported sleep questionnaire scores over 3 years in children with Smith-Magenis syndrome (SMS) compared to age-matched typically developing (TD) controls. We also aimed to (iii) describe individual profiles of change in sleep parameters over time.

Methods

Week-long, overnight actigraphy and questionnaire data from 13 children with SMS and 13 age-matched TD children were collected at Time 1 and Time 2 (3 years later). Independent samples t-tests, paired samples t-tests, and Bayesian analyses were used to compare sleep parameters and sleep questionnaire scores between groups at each time point and compare data within groups to assess change over time.

Results

Sleep parameters were consistently more disrupted in the SMS group than the TD group, with significantly reduced sleep efficiency, increased wake after sleep onset and earlier get up times at both time points. This was mirrored in the questionnaire data, with children with SMS evidencing higher scores for overall sleep disturbance, night waking, and daytime sleepiness. While TD sleep parameters demonstrated expected developmental changes over 3 years, in the SMS group sleep parameters and variability between and within children remained largely stable. However, some children with SMS showed substantial variation in sleep parameters over time. Questionnaire scores remained stable over 3 years in both groups.

Conclusions

Overall, sleep disturbance appears to be a stable feature of SMS, indicative of a divergent sleep trajectory compared to TD peers. Proactive intervention approaches should be considered for poor sleep in SMS.

What is the Sleep Pattern of Infants and Toddlers in the Iranian Population? An Epidemiological Study

Objective  To identify sleep patterns and sleep behaviors in a group of infants and toddlers (0 to 36 months) in Iran. Methods  Parents and caregivers of 602 infants and toddlers in Iran completed a Persian translation of the Brief Infant Sleep Questionnaire. To assess the differences among the age groups, non-parametric statistical approaches such as the Kruskal-Wallis and chi-square tests were employed. Results  The infants and toddlers went to bed relatively late (22:30), and the median night awakening was 2 times (20 min). They most likely slept in the same room with their parents (55.5%), and commonly in the same bed (18.9%). They slept a median of 11.50 hours per day. A significant percentage of the parents felt that their child had moderate or severe sleep problems (22.4%). These children's sleep patterns had significant developmental changes, including decreased daytime sleep, reduced overall sleep, and increased sleep consolidation (reduced number and duration of night awakenings and increased overall sleep duration). The parents commonly used holding-and-rocking and bottle/breastfeeding to initiate infants' sleep and bottle/breastfeeding to resume their infants' sleep. Discussion  These findings provide reference data for professionals to assess sleep in children under 3 years of age and also supply knowledge about common parenting practices related to a child's sleep. Cross-cultural comparisons using the findings can offer new insights into the practices and behaviors of parents concerning infant and toddler sleep.

Associations between sleep, reading, and mathematics in Taiwanese children

BACKGROUND

Some research shows a link between sleep behaviours and school achievement in English-speaking children and adolescents.

AIMS

The current study aimed to examine the relationship between children's sleep behaviours and aspects of their school achievement in Mandarin-speaking children who are living in Taiwan.

SAMPLE

The present study reports on 69 second-grade children (age range = 6.84-8.4 years) recruited in Taipei City, Taiwan.

METHODS

Children's sleep behaviours were assessed through two standardized parent self-report questionnaires: the Children's Sleep Habits Questionnaire (CSHQ) and the Sleep Disturbance Scale for Children (SDSC). Children undertook three standardized tests of word reading, reading comprehension and math.

RESULTS

Key findings include: (i) sleep disturbances are more prevalent when using the CSHQ scale than the SDSC scale, (ii) around half of second graders struggle with general sleep disturbances as observed by the CSHQ scale, (iii) children who go to bed before 22:00 and have at least 9-h sleep tend to exhibit fewer sleep disturbances, (iv) parasomnias as measured by the CSHQ are negatively correlated with reading comprehension after controlling age and nonverbal IQ, and (v) the amount of sleep (naps) during daytime is negatively correlated with Chinese character recognition, reading comprehension and math after controlling age and nonverbal IQ.

CONCLUSIONS

There is growing awareness of the value of research that spans culturally and linguistically diverse populations. Our study contributes to ongoing discussions about the relationship between sleep, and skills in reading and math in school-aged children in Taiwan.

Applying machine learning to consumer wearable data for the early detection of complications after pediatric appendectomy

When children are discharged from the hospital after surgery, their caregivers often rely on subjective assessments (e.g., appetite, fatigue) to monitor postoperative recovery as objective assessment tools are scarce at home. Such imprecise and one-dimensional evaluations can result in unwarranted emergency department visits or delayed care. To address this gap in postoperative monitoring, we evaluated the ability of a consumer-grade wearable device, Fitbit, which records multimodal data about daily physical activity, heart rate, and sleep, in detecting abnormal recovery early in children recovering after appendectomy. One hundred and sixty-two children, ages 3-17 years old, who underwent an appendectomy (86 complicated and 76 simple cases of appendicitis) wore a Fitbit device on their wrist for 21 days postoperatively. Abnormal recovery events (i.e., abnormal symptoms or confirmed postoperative complications) that arose during this period were gathered from medical records and patient reports. Fitbit-derived measures, as well as demographic and clinical characteristics, were used to train machine learning models to retrospectively detect abnormal recovery in the two days leading up to the event for patients with complicated and simple appendicitis. A balanced random forest classifier accurately detected 83% of these abnormal recovery days in complicated appendicitis and 70% of abnormal recovery days in simple appendicitis prior to the true report of a symptom/complication. These results support the development of machine learning algorithms to predict onset of abnormal symptoms and complications in children undergoing surgery, and the use of consumer wearables as monitoring tools for early detection of postoperative events.

The Italian language postpartum specific anxiety scale [PSAS-IT]: translation, psychometric evaluation, and validation

Introduction

While often positive, the lifecourse transition to motherhood is susceptible to the risk for developing mood disorders. Postpartum anxiety has often been overshadowed by other perinatal-specific mental health disorders, such as postpartum depression, and therefore has not been at the forefront or center of as much empirical study. This has meant there is a lack of effective and reliable tools with which to measure it, despite growing evidence suggesting its detrimental impact on mothers, their babies, wider family and social contacts, and on healthcare systems. This current study aimed to translate and validate the Postpartum Specific Anxiety Scale [PSAS] into the Italian language, and to validate the tool for its use in detecting anxiety specific to motherhood.

Methods

The study (N = 457) comprised 4 stages: English-Italian translation and back-translation to obtain the Italian version [PSAS-IT]; a preliminary pilot study to adapt the PSAS to the characteristics of the Italian population; measurement invariance; and internal reliability of subscales.

Results

The PSAS-IT demonstrates similar psychometric properties as the original English-language PSAS, with acceptable acceptability, construct and convergent validity, and internal consistency. Confirmatory factor analysis for multiple groups (Italy and United Kingdom) showed that the factor structure of the PSAS was valid for both groups [χ2 (2436) = 4679.481, p < 0.001, TLI = 0.969, CFI =0.972, RMSEA = 0.045, SRMR =0.064].

Discussion

The resulting findings offer a reliable measure of postpartum anxiety in Italian language up to six months after birth.

Prevalence and socio-demographic distributions of meeting RMI Guidelines for Healthy Living among elementary school children in Majuro, Republic of Marshall Islands: a cross-sectional population-based survey

Background

Childhood obesity is high in Republic of Marshall Islands (RMI). We report the prevalence and socio-demographic distribution of selected obesity-related risk factors among children in Majuro, RMI.

Methods

Sixteen elementary schools were approached and students and parents in Grades 1, 3, and 5 invited to participate in this cross-sectional population-based survey. Accelerometry and a questionnaire were used to collect data on children's physical activity (PA), sleep, screen time and dietary behaviours. Descriptive statistics and mixed-effects logistic regression were used to examine differences in the proportions of children meeting selected RMI Healthy Living Guidelines by sex, school grade and school sector.

Findings

Thirteen schools and 958 children were recruited, of which 892 (52.2% girls; mean age 9.3 ± 1.8 years) provided useable data. Around 90% met the PA, 29% screen time, 13% sleep, 69% sugar-sweetened beverage and 56% highly processed food guidelines. The proportion meeting individual guidelines was higher among children in Grade 1 compared with Grade 5. Being a girl (0.27; 95% CI 0.16, 0.46) was associated with lower odds of meeting the PA recommendation. Compared with children from Grade 1, those in Grade 5 had lower odds of meeting the PA (0.28; 95% CI 0.15, 0.55), screen time (0.60; 95% CI 0.40, 0.89), sleep duration (0.33; 95% CI 0.18, 0.59), sugar-sweetened beverage (0.35; 95% CI 0.23, 0.53), and consumption of highly processed foods recommendations (0.49; 95% CI 0.33, 0.72).

Interpretation

While most children in RMI are adequately active, resources are needed to promote healthier levels of screen time, sleep, sugar-sweetened beverage and highly processed food consumption, especially among older children.

Funding

This study was funded by World Diabetes Foundation; Canvasback Missions, RMI; NHMRC Australia (APP1176858); Pacific Community.

Psychometric evaluation of the postpartum specific anxiety scale - research short-form among iranian women (PSAS-IR-RSF)

BACKGROUND

The increasing prevalence of postpartum anxiety as a common psychological problem affects a large part of women's lives. Despite the existence of tools in this field, but due to the lack of specificity in reflecting postpartum anxiety, it is necessary to have a specific tool to screen it. Since the psychometric evaluation of the Postpartum Specific Anxiety Scale-Research Short-Form (PSAS-RSF) among Iranian women has not been assessed in Iran until now, so we decided to conduct this study with the aim of psychometric evaluation of the PSAS-IR-RSF.

METHODS

We included 180 women (six weeks to six months postpartum) in the study by random sampling during the period from December 2021 to June 2022. We examined the validity of the PSAS-IR-RSF tool in terms of face, content and construct (through exploratory and confirmatory factor analyses). We used internal consistency and test-retest reliability to determine the reliability of the scale.

RESULTS

In the present study, content validity index (CVI) and content validity ratio (CVR) of the PSAS-IR-RSF tool were equal to 0.91 and 0.97, respectively. We extracted a four-factor structure through the process of exploratory factor analysis. The values of fitting indices confirmed the validity of the model. Cronbach's alpha coefficient was equal to 0.72 and intra-class correlation coefficient (with 95% confidence interval) was 0.97 (0.98 to 0.93).

CONCLUSIONS

The Persian version of the PSAS-IR-RSF is a valid and reliable tool for the specific evaluation of postpartum anxiety among Iranian women.

24 h Activity Guidelines in Children and Adolescents: A Prevalence Survey in Asia-Pacific Cities

This study aimed to examine the prevalence of adherence to 24 h activity guidelines in children and adolescents from Asia-Pacific cities. In 1139 children aged 5-18 years, moderate-to-vigorous physical activity (MVPA), screen viewing time (SVT), sleep duration, child weight, height, sex, and age were parent-reported. Descriptive statistics were used to assess the number of guidelines met, and prevalence of adherence to activity guidelines by city and child sex. Prevalence of meeting all three 24 h activity guidelines was low across all countries (1.8-10.3%) (p < 0.05). Children from Thiruvananthapuram, India had the highest [10.3% (95% CI: 6.0-17.0)], while those from Tokyo, Japan had the lowest prevalence [1.8% (95% CI: 0.5-7.0)] of meeting all three guidelines. The highest prevalence of meeting individual MVPA, SVT and sleep guidelines was found in India [67.5% (95% CI: 58.8-75.1)], Kelaniya, Sri Lanka [63.2% (95% CI: 58.7-67.4)] and Kowloon, Hong Kong [59.4% (95% CI: 51.1-65.3)], respectively. Overall, a higher prevalence of boys met all three guidelines, compared to girls [5.9% (95% CI: 4.1-8.1) vs. 4.7% (3.1-6.6), p = 0.32]. The prevalence of adhering to all three activity guidelines was low in all five participating cities, with a higher proportion of boys meeting all guidelines.

Pediatric sleep: current knowledge, gaps, and opportunities for the future

This White Paper addresses the current gaps in knowledge, as well as opportunities for future studies in pediatric sleep. The Sleep Research Society's Pipeline Development Committee assembled a panel of experts tasked to provide information to those interested in learning more about the field of pediatric sleep, including trainees. We cover the scope of pediatric sleep, including epidemiological studies and the development of sleep and circadian rhythms in early childhood and adolescence. Additionally, we discuss current knowledge of insufficient sleep and circadian disruption, addressing the neuropsychological impact (affective functioning) and cardiometabolic consequences. A significant portion of this White Paper explores pediatric sleep disorders (including circadian rhythm disorders, insomnia, restless leg and periodic limb movement disorder, narcolepsy, and sleep apnea), as well as sleep and neurodevelopment disorders (e.g. autism and attention deficit hyperactivity disorder). Finally, we end with a discussion on sleep and public health policy. Although we have made strides in our knowledge of pediatric sleep, it is imperative that we address the gaps to the best of our knowledge and the pitfalls of our methodologies. For example, more work needs to be done to assess pediatric sleep using objective methodologies (i.e. actigraphy and polysomnography), to explore sleep disparities, to improve accessibility to evidence-based treatments, and to identify potential risks and protective markers of disorders in children. Expanding trainee exposure to pediatric sleep and elucidating future directions for study will significantly improve the future of the field.

Psychometric Properties and Factorial Structure of Postpartum-Specific Anxiety Scale (PSAS) Within Arabic Language in a Palestinian Context

BACKGROUND

The Postpartum-Specific Anxiety Scale (PSAS) is an international measure designed to evaluate anxiety experienced by mothers in the postpartum period from one day to six months; the scale was translated into Arabic and validated within Palestinian context to test postpartum anxiety among Palestinian women.

AIMS

The current study aimed to test the psychometric properties and the factorial structure within the Arabic language in a Palestinian context using confirmatory factor analysis (CFA). The sample of this study consisted of 475 Palestinian women recruited from health centers in the West Banks of Palestine using a convenience sample. 61% were of ages 20-30 years and 39% percent ages 31-40 years.

FINDINGS

The PSAS showed good validity and reliability indicators in assessing postpartum anxiety within Palestinian context. Results of CFA showed a stable construct of a four-factor structure in assessing postpartum anxiety among Palestinian mothers: (1) competence and attachment anxieties, (2) infant safety and welfare anxieties, (3) practical baby care anxieties and (4) psychosocial adjustment to motherhood, which is consisting with the original four-factor structure of the scale.

CONCLUSIONS

The PSAS showed good validity indicators within Palestinian context. Therefore, it is recommended to conduct similar studies with clinical and non-clinical groups in the Palestinian society. The PSAS can be a useful measure to assess anxiety levels among women during the postpartum months; which will enable mental health providers to provide psychological interventions for mothers whose anxiety levels are high.

Sleep, 24-hour activity rhythms, and cardiometabolic risk factors in school-age children

STUDY OBJECTIVES

Disturbed sleep and 24-hour activity rhythms are linked to adverse cardiometabolic profiles in adults and adolescents, and these associations may originate in early life. We aimed to study associations of sleep and 24-hour rhythms with cardiometabolic risk factors in school-age children.

METHODS

This cross-sectional population-based study comprised 894 children aged 8-11 years from the Generation R Study. Sleep (duration, efficiency, number of awakenings, and time awake after sleep onset) and 24-hour activity rhythms (social jet lag, interdaily stability, and intradaily variability) were assessed using triaxial wrist actigraphy for 9 consecutive nights. Cardiometabolic risk factors included adiposity (body mass index Z-score, fat mass index using dual-energy X-ray absorptiometry, and visceral fat mass and liver fat fraction using magnetic resonance imaging), blood pressure, and blood markers (glucose, insulin, and lipids). We adjusted for season, age, sociodemographics, and lifestyle factors.

RESULTS

Each increase in interquartile range of nightly awakenings (2 times) was associated with -0.12 standard deviation (95% confidence interval: -0.21, -0.04) lower body mass index and 0.15 mmol/L (0.10, 0.21) higher glucose. Among boys, an increase in interquartile range of intradaily variability (0.12) was associated with higher fat mass index (+0.07 kg/m2; 95% confidence interval: 0.03, 0.11) and visceral FM (+0.08 g; 95% confidence interval: 0.02, 0.15). We observed no associations with blood pressure or clustering of cardiometabolic risk factors.

CONCLUSIONS

Already at school age, greater fragmentation of the 24-hour activity rhythm is associated with general and organ adiposity. In contrast, more nightly awakenings were associated with lower body mass index. Future research should bring clarity to these disparate observations in order to create potential targets for obesity prevention programs.

CITATION

Beunders VAA, Koopman-Verhoeff ME, Vermeulen MJ, et al. Sleep, 24-hour activity rhythms, and cardiometabolic risk factors in school-age children. J Clin Sleep Med. 2023;19(7):1219-1229.

School-Based Sleep Education Program for Children: A Cluster Randomized Controlled Trial

Insufficient sleep contributes negatively to child developmental processes and neurocognitive abilities, which argues the need for implementing interventions to promote sleep health in children. In this study, we evaluated the effectiveness of a multimodal and multilevel school-based sleep education program in primary school children using a cluster randomized controlled design. Twelve schools were randomly assigned to either the sleep education or nonactive control groups. The sleep education group included a town hall seminar, small class teaching, leaflets, brochures, and a painting competition for children. Parents and teachers were invited to participate in a one-off sleep health workshop. Parental/caregiver-reported questionnaires were collected at baseline and 1-month follow-up. A total of 3769 children were included in the final analysis. There were no significant improvements observed in the sleep-wake patterns, daytime functioning, and insomnia symptoms between the two groups at follow-up, whereas the intervention group had significantly improved parental sleep knowledge than the controls (paternal: adjusted mean difference: 0.95 [95% confidence interval (CI): 0.18 to 1.71]; maternal: adjusted mean difference: 0.87 [95% CI: 0.17 to 1.57]). In addition, children receiving the intervention had a lower persistence rate of excessive beverage intake (adjusted odds ratio: 0.49 [95% CI: 0.33 to 0.73]), and experienced greater reductions in conduct problems (adjusted mean difference: 0.12 [95% CI: 0.01 to 0.24]) compared with the controls at 1-month of follow-up. Moreover, a marginally significant reduction for emotional problems in the intervention group was also observed (adjusted mean difference: 0.16 [95% CI: -0.00 to 0.32]). These findings demonstrated that school-based sleep education was effective in enhancing parental sleep knowledge and improving behavioral outcomes in children, but not sufficient in altering the children's sleep-wake patterns and sleep problems.

What daily factors affect the sleep habits of Japanese toddlers?

STUDY OBJECTIVES

Good sleep, especially during early childhood, is important for development. In Japan, the mean nocturnal sleep duration of toddlers is < 10 hours, and even if toddlers slept for > 11 hours/day, as recommended by the National Sleep Foundation, some of them showed late bedtime and late wake-up time or took long naps. Therefore, we provisionally assumed the minimal sleep conditions for Japanese toddlers, named Nenne-criteria, such as bedtime before 10:00 pm, nocturnal sleep duration of ≥ 9 hours, and < 1 average time of awakening after sleep onset, and investigated the important factors for good sleep.

METHODS

We analyzed cross-sectional data from online surveys describing the sleep-related behaviors of 2,124 toddlers and their caregivers. We compared the daily schedules that affect sleep between the Nenne-criteria-meet group and the not-meet group.

RESULTS

The Nenne-criteria-meet group showed better daytime behaviors than the not-meet group. Structural equation modeling on daily schedules revealed that, to increase sleep pressure at the appropriate time, it is important to restrict media viewing, play outdoors in the morning, have an early nap ending time, avoid hyperarousal-inducing behaviors before bedtime, maintain daily schedules regularly, and decrease social jetlag.

CONCLUSIONS

The Nenne-criteria are useful for screening Japanese toddlers who require intervention for sleep hygiene. To improve toddlers' sleep, it is important not only to guide the ideal bedtime but also to provide tips for improving daily schedules and to avoid suboptimal sleep-related behaviors.

CITATION

Murata E, Yoshizaki A, Fujisawa TX, Tachibana M, Taniike M, Mohri I. What daily factors affect the sleep habits of Japanese toddlers? J Clin Sleep Med. 2023;19(6):1089-1101.

Baby Brains at Work: How Task-Based Functional Magnetic Resonance Imaging Can Illuminate the Early Emergence of Psychiatric Risk

Psychiatric disorders are complex, often emerging from multiple atypical processes within specified domains over the course of development. Characterizing the development of the neural circuits supporting these domains may help break down the components of complex disorders and reveal variations in functioning associated with psychiatric risk. This review highlights the current and potential role of infant task-based functional magnetic resonance imaging (fMRI) in elucidating the developmental neurobiology of psychiatric disorders. Task-fMRI measures evoked brain activity in response to specific stimuli through changes in the blood oxygen level-dependent signal. First, we review extant studies using task fMRI from birth through the first few years of life and synthesize current evidence for when, where, and how different neural computations are performed across the infant brain. Neural circuits for sensory perception, the perception of abstract categories, and the detection of statistical regularities have been characterized with task fMRI in infants, providing developmental context for identifying and interpreting variation in the functioning of neural circuits related to psychiatric risk. Next, we discuss studies that specifically examine variation in the functioning of these neural circuits during infancy in relation to risk for psychiatric disorders. These studies reveal when maturation of specific neural circuits diverges, the influence of environmental risk factors, and the potential utility for task fMRI to facilitate early treatment or prevention of later psychiatric problems. Finally, we provide considerations for future infant task-fMRI studies with the potential to advance understanding of both functioning of neural circuits during infancy and subsequent risk for psychiatric disorders.

Factors that influence outcomes and device use for pediatric cochlear implant recipients with unilateral hearing loss

Introduction

Candidacy criteria for cochlear implantation in the United States has expanded to include children with single-sided deafness (SSD) who are at least 5 years of age. Pediatric cochlear implant (CI) users with SSD experience improved speech recognition with increased daily device use. There are few studies that report the hearing hour percentage (HHP) or the incidence of non-use for pediatric CI recipients with SSD. The aim of this study was to investigate factors that impact outcomes in children with SSD who use CIs. A secondary aim was to identify factors that impact daily device use in this population.

Methods

A clinical database query revealed 97 pediatric CI recipients with SSD who underwent implantation between 2014 and 2022 and had records of datalogs. The clinical test battery included speech recognition assessment for CNC words with the CI-alone and BKB-SIN with the CI plus the normal-hearing ear (combined condition). The target and masker for the BKB-SIN were presented in collocated and spatially separated conditions to evaluate spatial release from masking (SRM). Linear mixed-effects models evaluated the influence of time since activation, duration of deafness, HHP, and age at activation on performance (CNC and SRM). A separate linear mixed-effects model evaluated the main effects of age at testing, time since activation, duration of deafness, and onset of deafness (stable, progressive, or sudden) on HHP.

Results

Longer time since activation, shorter duration of deafness, and higher HHP were significantly correlated with better CNC word scores. Younger age at device activation was not found to be a significant predictor of CNC outcomes. There was a significant relationship between HHP and SRM, with children who had higher HHP experiencing greater SRM. There was a significant negative correlation between time since activation and age at test with HHP. Children with sudden hearing loss had a higher HHP than children with progressive and congenital hearing losses.

Conclusion

The present data presented here do not support a cut-off age or duration of deafness for pediatric cochlear implantation in cases of SSD. Instead, they expand on our understanding of the benefits of CI use in this population by reviewing the factors that influence outcomes in this growing patient population. Higher HHP, or greater percentage of time spent each day using bilateral input, was associated with better outcomes in the CI-alone and in the combined condition. Younger children and those within the first months of use had higher HHP. Clinicians should discuss these factors and how they may influence CI outcomes with potential candidates with SSD and their families. Ongoing work is investigating the long-term outcomes in this patient population, including whether increasing HHP after a period of limited CI use results in improved outcomes.

Sleep and 24-hour rhythm characteristics in preschool children born very preterm and full term

STUDY OBJECTIVES

Sleep impacts the quality of life and is associated with cardiometabolic and neurocognitive outcomes. Little is known about the sleep of preterm-born children at preschool age. We, therefore, studied sleep and 24-hour rhythms of preschool children born very preterm compared with full-term children.

METHODS

This was a prospective cohort study comparing sleep quality and quantity of children born very preterm (gestational age [GA] < 30 weeks) with full-term children at the (corrected) age of 3 years, using (1) 2 parent-reported questionnaires (Brief Infant Sleep Questionnaire and The Munich Chronotype Questionnaire) and (2) at least 3 days of triaxial wrist actigraphy combined with sleep diary. We performed regression analyses with adjustment for sex (corrected), age, and birth weight standard deviation (SD) score.

RESULTS

Ninety-seven very-preterm-born (median GA 27+5; interquartile range 26 + 3;29 + 0 weeks) and 92 full-term children (GA 39 + 3; 38 + 4;40 + 4 weeks) were included. Sleep problems and other reported sleep parameters were not different between groups. As measured with actigraphy, sleep and 24-hour rhythm were similar between groups, except for very-preterm born children waking up 21 minutes (4;38) minutes later than full-term children (adjusted P = .001).

CONCLUSIONS

Based on parent reports and actigraphy, very-preterm-born children sleep quite similar to full-term controls at the corrected age of 3 years. Reported sleep problems were not different between groups. Actigraphy data suggest that preterm-born children may wake up later than children born full term. Further studies are needed to explore how sleep relates to cardiometabolic and neurodevelopmental outcomes after preterm birth and whether early interventions are useful to optimize 24-hour rhythm and sleep.

CITATION

Bijlsma A, Beunders VAA, Dorrepaal DJ, et al. Sleep and 24-hour rhythm characteristics in preschool children born very preterm and full term. J Clin Sleep Med. 2023;19(4):685-693.

Sleep habits and sleep disorders in Italian children and adolescents: a cross-sectional survey

STUDY OBJECTIVES

The aim was to describe sleep habits and epidemiology of the most common sleep disorders in Italian children and adolescents.

METHODS

This was a cross-sectional study in which parents of typically developing children and adolescents (1-18 years) completed an online survey available in Italy, gathering retrospective information focusing on sleep habits and disorders.

RESULTS

Respondents were 4,321 typically developing individuals (48.6% females). Most of our sample did not meet the age-specific National Sleep Foundation recommendations for total sleep duration (31.9% of toddlers, 71.5% of preschoolers, 61.6% of school-age children, and 41.3% of adolescents). Napping was described in 92.6% of toddlers and in 35.2% of preschoolers. Regarding geographical differences, children and adolescents of northern Italy showed more frequent earlier bedtimes and rise times than their peers of central and southern Italy. The most frequently reported sleep disorder in our sample was restless sleep (35.6%), followed by difficulties falling asleep (16.8%), > 2 night awakenings (9.9%), and bruxism (9.6%). Data also suggest that longer screen time is associated with later bedtimes on weekdays in all age groups.

CONCLUSIONS

The current study shows that Italian children are at risk of sleep disorders, particularly insufficient sleep, restless sleep, and difficulty falling asleep. The study also provides normative sleep data by age group in a large cohort of typically developing Italian children, emphasizing the importance of the developmentally, ecologically, and culturally based evaluation of sleep habits and disorders.

CITATION

Breda M, Belli A, Esposito D, et al. Sleep habits and sleep disorders in Italian children and adolescents: a cross-sectional survey. J Clin Sleep Med. 2023;19(4):659-672.

Associations between demographic and parental factors and infant sleep characteristics

Although sleep problems are highly prevalent in infants, the intrinsic and extrinsic factors that influence sleep consolidation and regulation in this age group are not well understood. This study aimed to examine the cross-sectional associations of demographic and parental factors with infant sleep characteristics. Participants were 97 Canadian mother-infant dyads primarily from Edmonton, Alberta. Demographic factors (e.g., infant age), parenting practices (e.g., sleep position, sleep initiation methods), and infants sleep characteristics (e.g., the frequency of nighttime awakenings) were assessed using the Brief Infant Sleep Questionnaire. Maternal sleep characteristics (e.g., nighttime sleep duration) were assessed using Actigraph accelerometers. Infant age (mean = 4.24 ± 2.90) was associated with most infant sleep characteristics. In multiple regression models for infant nighttime sleep duration, after removing influential observations, a negative association for side (vs. prone) sleep position was, respectively, observed. In multiple regression models for the frequency of nighttime awakenings in infants, positive associations for infants falling asleep while feeding (vs. in bed alone) and side (vs. prone) sleep position were consistently observed after removing influential observations. Lower nighttime sleep efficiency (B =  - 0.08, 95%CI: - 0.13, - 0.02) and longer nighttime wake after sleep onset (B = 1.03, 95%CI: 0.41, 1.65) in mothers were associated with more frequent nighttime awakenings in infants. After removing influential observations, more frequent nighttime awakenings (B = 0.35; 95%CI: 0.09, 0.61) and longer total sleep duration (B = 0.33, 95%CI: 0.11, 0.55) in mothers were also associated with more frequent nighttime awakenings in infants. Sleep initiation methods with less parental involvement, and more continuous and efficient maternal nighttime sleep, tended to be associated with less interrupted infant sleep.

Associations between sleep trajectories up to 54 months and cognitive school readiness in 4 year old preschool children

Purpose

This study explores the association between the duration and variation of infant sleep trajectories and subsequent cognitive school readiness at 48–50 months.

Methods

Participants were 288 multi-ethnic children, within the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort. Caregiver-reported total, night and day sleep durations were obtained at 3, 6, 9, 12, 18, 24 using the Brief Infant Sleep Questionnaire and 54 months using the Child Sleep Habits Questionnaire. Total, night and day sleep trajectories with varying durations (short, moderate, or long) and variability (consistent or variable; defined by standard errors) were identified. The cognitive school readiness test battery was administered when the children were between 48 and 50 months old. Both unadjusted adjusted analysis of variance models and adjusted analysis of covariance models (for confounders) were performed to assess associations between sleep trajectories and individual school readiness tests in the domains of language, numeracy, general cognition and memory.

Results

In the unadjusted models, children with short variable total sleep trajectories had poorer performance on language tests compared to those with longer and more consistent trajectories. In both unadjusted and adjusted models, children with short variable night sleep trajectories had poorer numeracy knowledge compared to their counterparts with long consistent night sleep trajectories. There were no equivalent associations between sleep trajectories and school readiness performance for tests in the general cognition or memory domains. There were no significant findings for day sleep trajectories.

Conclusion

Findings suggest that individual differences in longitudinal sleep duration patterns from as early as 3 months of age may be associated with language and numeracy aspects of school readiness at 48–50 months of age. This is important, as early school readiness, particularly the domains of language and mathematics, is a key predictor of subsequent academic achievement.

Consensus recommendations on sleeping problems in Phelan-McDermid syndrome

Early onset sleep problems and disorders are very common in individuals with Phelan-McDermid Syndrome (PMS) with rates of up to 90%. These sleep problems and disorders cannot be taken lightly. Not only do they have a major impact on the health, behaviour, functioning and learning opportunities of affected individuals, they can also have detrimental effects on the well-being and resilience of parents and caregivers, ultimately affecting the physical health, mental health and well-being of the whole social system. In this review we aim to understand the types and frequencies of sleeping problems in PMS as the basis for recommendations on their management and treatment and to provide general guidelines for clinicians and practitioners. We conducted an in-depth literature search, summarised findings, and participated in a series of consensus meetings with other consortium members - experts on PMS and stakeholders - to agree on guidelines and recommendations. In parallel, a world-wide survey was created and distributed amongst parents to include their perspective. Our literature search found only three articles specifically focused on sleeping problems in PMS, although some other articles mentioned prevalence and associated factors. Country-specific prevalence rates ranged between 24% and 46%, whereas our parental survey reported 59%. The main problems reported involved difficulty falling asleep and numerous night awakenings, with being restless in sleep, night-time incontinence, and tooth grinding also commonly reported. Only a small number of individuals had undergone a sleep study monitored by a specialist. Bedtime resistance normally decreases with age, but sleep-onset delay, sleep anxiety, parasomnias, problems falling and remaining asleep remain throughout lifespan, with total sleep time improving during adulthood. However, this improvement was also accompanied by a substantial increase in parasomnias. Ultimately, an increase in sleep disorders in children correlates with increased sleep disorders and daytime sleepiness in parents/caregivers. No study to date has focused on the underlying causes of sleeping problems in PMS, but comorbid mental health conditions, somatic causes, or (poly)pharmacy have been proposed as triggers for sleeping disturbances. Currently there is no PMS-specific treatment for sleeping problems, and current recommendations are mostly based on individuals with intellectual disability and/or neurodevelopmental conditions.

Reference centiles for infant sleep parameters from 4 to 16 weeks of age: findings from an Irish cohort

OBJECTIVES

To establish unconditional reference centiles for sleep parameters in infants 4-16 weeks of age.

DESIGN AND SETTING

Secondary data analysis of sleep parameters recorded at 4-16 weeks of age in a longitudinal randomised controlled trial (RCT) (BabySMART).

PATIENTS

Healthy term infants assigned to the non-intervention arm of the RCT.

MAIN OUTCOME MEASURES

Infants' sleep duration was recorded by parents/guardians daily, from week 2-16 of age using a sleep diary. Reference centiles for total, daytime, night-time and longest sleep episode duration were estimated using multilevel modelling.

RESULTS

One hundred and six infants, mean (SD) gestational age of 39.9 (1.2) weeks and mean (SD) birth weight of 3.6 (0.5) kg had sleep recorded contributing 1264 measurements for each sleep parameter. Between 4 and 16 weeks of age total sleep duration in a 24-hour period, night-time sleep duration in a 12-hour period and infant's longest sleep episode duration increased, while daytime sleep duration in a 12-hour period decreased.

CONCLUSIONS

Reference centiles up to 4 months of age in infants highlight the gradual decrease in daytime sleep and large increases in night-time sleep, which occur in tandem with increasing lengths of sleep episodes. These reference centiles provide useful sleep values for infant sleep trajectory occurring in early life and may be helpful for parents and clinicians.

TRIAL REGISTRATION NUMBER

NCT03381027.

A circuit-level biomarker of Rett syndrome based on ectopic phase-amplitude coupling during slow-wave-sleep

Rett syndrome (RTT) is a neurodevelopmental disorder characterized by loss of purposeful hand use and spoken language following an initial period of normal development. Although much is known about the genetic and molecular underpinnings of RTT, less is known about the circuit-level etiopathology. Coupling of oscillations during slow-wave-sleep (SWS) underlies important neurocognitive processes in adulthood, yet its emergence has yet to be described in early typical development (TD) or in RTT. We therefore addressed these unknowns by describing SWS cross-frequency coupling in both RTT and early TD using a retrospective study design. We found that in TD, phase-amplitude coupling (PAC) during SWS was dominated by coupling of slow-wave (0.5-2 Hz) phase to theta amplitude (5-8 Hz, "SW:T") as well as slow-wave to spindle-range (12-15 Hz, "SW:S"). Coupling exhibited characteristic vertex-prominent spatial topography, which emerged during an early developmental window. This topography failed to develop in patients with RTT due to persistent ectopic coupling. Furthermore, we found that subtypes of RTT exhibit distinct PAC topographic profiles, and that ectopic PAC correlates with clinical severity. These findings suggest that altered PAC dynamics and spatial organization during SWS may underlie the circuit-level pathophysiology of RTT and suggest that ectopic coupling may contribute to RTT pathogenesis.

Infant motor development predicts the dynamics of movement during sleep

The characteristics of infant sleep change over the first year. Generally, infants wake and move less at night as they grow older. However, acquisition of new motor skills leads to temporary increases in night waking and movement at night. Indeed, sleep-dependent movement at night is important for sensorimotor development. Nevertheless, little is known about how movement during sleep changes as infants accrue locomotor experience. The current study investigated whether infant sleep and movement during sleep were predicted by infants' walking experience. Seventy-eight infants wore an actigraph to measure physical activity during sleep. Parents reported when their infants first walked across a room >10 feet without stopping or falling. Infants in the midst of walking skill acquisition had worse sleep than an age-group estimate. Infants with more walk experience had more temporally sporadic movement during sleep and a steeper hourly increase in physical activity over the course of the night. Ongoing motor skill consolidation changes the characteristics of movement during sleep and may alter sleep state-dependent memory consolidation. We propose a model whereby changes in gross motor activity during night sleep reflect movement-dependent consolidation.