Less Efficient Neural Processing Related to Irregular Sleep and Less Sustained Attention in Toddlers

The P3 ERP in Relation to General Versus Specific Psychopathology in Early Childhood

There is considerable covariation between externalizing and internalizing problems across the lifespan. Partitioning general and specific psychopathology is crucial to identify (a) processes that confer specific risk for externalizing versus internalizing problems and (b) transdiagnostic processes that confer risk for the covariation between externalizing and internalizing problems. The oddball P3 event-related potential (ERP) component, thought to reflect attentional orienting, has been widely examined in relation to psychopathology. However, prior studies have not examined the P3-or other aspects of neural functioning-in relation to general versus specific psychopathology in children. The present study examined whether children's (N = 124, ages 3-7 years) P3 amplitudes were associated with general versus specific psychopathology. Children's electroencephalography data were recorded during an oddball task. Parents rated their children's externalizing and internalizing problems. Using bifactor models to partition variance in parents' ratings of children's psychopathology symptoms, we examined children's P3 amplitudes in relation to three latent factors: (1) the general factor of psychopathology-the covariation of externalizing and internalizing psychopathology, (2) unique externalizing problems-the variance in externalizing problems after controlling for the general factor, and (3) unique internalizing problems. Results indicated that smaller P3 amplitudes were associated with unique externalizing problems at ages 3-5, and with general psychopathology at ages 6-7. Findings suggest that smaller P3 amplitudes may be associated with externalizing problems from a very young age. Moreover, there may be a developmental shift in the functional significance of the P3 in relation to general and specific psychopathology in childhood.

Rapid Eye Movement Sleep during Early Life: A Comprehensive Narrative Review

The ontogenetic sleep hypothesis suggested that rapid eye movement (REM) sleep is ontogenetically primitive. Namely, REM sleep plays an imperative role in the maturation of the central nervous system. In coincidence with a rapidly developing brain during the early period of life, a remarkably large amount of REM sleep has been identified in numerous behavioral and polysomnographic studies across species. The abundant REM sleep appears to serve to optimize a cerebral state suitable for homeostasis and inherent neuronal activities favorable to brain maturation, ranging from neuronal differentiation, migration, and myelination to synaptic formation and elimination. Progressively more studies in Mammalia have provided the underlying mechanisms involved in some REM sleep-related disorders (e.g., narcolepsy, autism, attention deficit hyperactivity disorder (ADHD)). We summarize the remarkable alterations of polysomnographic, behavioral, and physiological characteristics in humans and Mammalia. Through a comprehensive review, we offer a hybrid of animal and human findings, demonstrating that early-life REM sleep disturbances constitute a common feature of many neurodevelopmental disorders. Our review may assist and promote investigations of the underlying mechanisms, functions, and neurodevelopmental diseases involved in REM sleep during early life.

Higher Tablet Use Is Associated With Better Sustained Attention Performance but Poorer Sleep Quality in School-Aged Children

There are growing concerns that increased screen device usage may have a detrimental impact on classroom behaviour and attentional focus. The consequences of screen use on child cognitive functioning have been relatively under-studied, and results remain largely inconsistent. Screen usage may displace the time usually spent asleep. The aim of this study was to examine associations between screen use, behavioural inattention and sustained attention control, and the potential modifying role of sleep. The relations between screen use, behavioural inattention, sustained attention and sleep were investigated in 162 6- to 8-year-old children, using parent-reported daily screen use, the SWAN ADHD behaviour rating scale, The sustained attention to response task and the children’s sleep habits questionnaire. Tablet use was associated with better sustained attention performance but was not associated with classroom behavioural inattention. Shorter sleep duration was associated with poorer behavioural inattention and sustained attention. Sleep quality and duration did not act as mediators between screen usage and behavioural inattention nor sustained attention control. These findings suggest that careful management of the amount of time spent on electronic screen devices could have a beneficial cognitive impact on young children. The results also highlight the critical role of sleep in enhancing both behavioural attention and sustained attention, which are essential for supporting cognitive development and learning.

Sustained attention across toddlerhood: The roles of language and sleep

The present study examined individual differences in the development of sustained attention across toddlerhood, as well as how these individual differences related to the development of language and sleep. Toddlers (N = 314; 54% male) were assessed at 30, 36, and 42 months using multiple measures of attention, a standardized language assessment, and actigraphic measures of sleep. Toddlers were 80% White. Family socioeconomic status (SES) was calculated using the Hollingshead Four Factor Index and ranged from 13 to 66 (M = 47.59, SD = 14.13). Aims were (a) to examine associations between measures of attention across situations, informants, and time; (b) to consider the independent and interactive effects of language and sleep on attention; and (c) to test potential bidirectional associations between sleep and attention. Findings showed attention measures were stable across time but were only weakly linked with each other at 42 months. Attention was consistently linked with language. More variable sleep and longer naps were associated with less growth in sustained attention across time. Nighttime sleep duration interacted with language in that sleep duration was positively associated with attention scores among toddlers with less advanced language, even when SES was controlled. The findings describe an understudied aspect of how sustained attention develops, involving the main effect of consistent sleep schedules and the interaction effect of amount of sleep and child language development. These findings are relevant to understanding early childhood risk for developing attention problems and to exploring a potential prevention target in family sleep practices. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

In Quest of Pathognomonic/Endophenotypic Markers of Attention Deficit Hyperactivity Disorder (ADHD): Potential of EEG-Based Frequency Analysis and ERPs to Better Detect, Prevent and Manage ADHD

Attention deficit hyperactivity disorder (ADHD) is a chronic heritable developmental delay psychiatric disorder requiring chronic management, characterized by inattention, hyperactivity, hyperkinectivity and impulsivity. Subjective clinical evaluation still remains crucial in its diagnosis. Discussed are two key aspects in the “characterizing ADHD” and on the quest for objective “pathognomonic/endophenotypic diagnostic markers of ADHD”. The first aspect briefly revolves around issues related to identification of pathognomonic/endophenotypic diagnostic markers in ADHD. Issues discussed include changes in ADHD definition, remission/persistence and overlapping-symptoms cum shared-heritability with its co-morbid cross-border mental disorders. The second aspect discussed is neurobiological and EEG-based studies on ADHD. Given the neurobiological and temporal aspects of ADHD symptoms the electroencephalograph (EEG) like NeuralScan by Medeia appears as an appropriate tool. The EEGs appropriateness is further enhanced when coupled with suitable behavior/cognitive/motor/psychological tasks/paradigms yielding EEG-based markers like event-related-potential (ERPs like P3 amplitudes and latency), reaction time variability (RTV), Theta:Beta ratio (TBR) and sensorimotor rhythm (SMR). At present, these markers could potentially help in the neurobiological characterization of ADHD and either help in identifying or lay the groundwork for identifying pathognomonic and/or endophenotypic EEG-based markers enabling its diagnosis, treatment and management.

Transient neonatal sleep fragmentation results in long-term neuroinflammation and cognitive impairment in a rabbit model

Sleep fragmentation is an increase in sleep-wake transitions without an overall decrease in total sleep time. Sleep fragmentation is well documented during acute and chronic hospitalization and can result in delirium and memory problems in children. Sleep fragmentation is also often noted in neurodevelopmental disorders. However, it is unclear how sleep fragmentation independent of disease affects brain development and function. We hypothesized that acute sleep fragmentation during the neonatal period in otherwise healthy animals would result in neuroinflammation and would be associated with abnormalities in cognitive development. The orbital shaker method was used to fragment sleep for 72 h in postnatal day 3 New Zealand white rabbit kits (fragmentation group). To control for maternal separation, the sham group was separated from the dam and maintained in the same conditions without undergoing sleep fragmentation. A naïve control group remained with the dam. Kits underwent behavioral testing with novel object recognition and spontaneous alternation T-maze tests at 2-3 weeks post-fragmentation and were sacrificed 3-50 days after fragmentation. Sleep fragmentation resulted in acute and chronic changes in microglial morphology in the hippocampus and cortex, and regional differences in mRNA expression of pro- and anti-inflammatory cytokines at 3, 7 and 50 days post-fragmentation. Impaired novel object recognition and a longer latency in T-maze task completion were noted in the fragmented kits. This was in spite of normalization of sleep architecture noted at 2 months of age in these kits. The results indicate that transient neonatal sleep fragmentation results in short-term and long-term immune alterations in the brain, along with diminished performance in cognitive tasks long-term.

Conducting Event-Related Potential (ERP) Research with Young Children: A Review of Components, Special Considerations and Recommendations for Research on Cognition and Emotion

There has been an unprecedented increase in the number of research studies employing event-related potential (ERP) techniques to examine dynamic and rapidly-occurring neural processes with children during the preschool and early childhood years. Despite this, there has been little discussion of the methodological and procedural differences that exist for studies of young children versus older children and adults. That is, reviewers, editors, and consumers of this work often expect developmental studies to simply apply adult techniques and procedures to younger samples. Procedurally, this creates unrealistic expectations for research paradigms, data collection, and data reduction and analyses. Scientifically, this leads to inappropriate measures and methods that hinder drawing conclusions and advancing theory. Based on ERP work with preschoolers and young children from 10 laboratories across North America, we present a summary of the most common ERP components under study in the area of emotion and cognition in young children along with 13 realistic expectations for data collection and loss, laboratory procedures and paradigms, data processing, ERP averaging, and typical challenges for conducting this type of work. This work is intended to supplement previous guidelines for work with adults and offer insights to aid researchers, reviewers, and editors in the design and evaluation of developmental research using ERPs. Here we make recommendations for researchers who plan to conduct or who are conducting ERP studies in children between ages 2 and 12, focusing on studies of toddlers and preschoolers. Recommendations are based on both data and our cumulative experience and include guidelines for laboratory setup, equipment and recording settings, task design, and data processing.

Mind-wandering, or the allocation of attentional resources, is sleep-driven across childhood

Mind-wandering or the spontaneous, uncontrolled changes in the allocation of attention resources (lapses) may cause variability in performance. In childhood, the relationship between the activation state of the brain, such as in attentional performance, and sleep has not been explored in detail. We investigated the role of sleep in attentional performance, and explored the most important parameters of their relationship. We objectively measured momentary lapses of attention of 522 children and correlated them with sleep schedules. In the subgroup of young children (age 7.1 ± 0.6 years; 60.8% girls), increasing age, long sleep duration and assessment closer to the previous night’s sleep period was associated with impaired performance speed and consistency. From pre-adolescence (age 9.4 ± 0.8 years; 50.5% girls) onwards somno-typologies may develop. As a result, in adolescence (age 13.4 ± 1.2 years; 51.3% girls) not only sleep duration but also sleep midpoint and sleep regularity influence the individual speed and stability of attention. Across development, regularity of sleep, individual sleep midpoint and bedtime become increasingly important for optimal performance throughout the day. Attentional performance and sleep shared almost half of their variance, and performance was sleep-driven across childhood. Future studies should focus on intra- and inter-individual differences in sleep-wake behavior to improve performance or decrease mind-wandering in youth by targeting sleep habits.

Correlates of nocturnal sleep duration, nocturnal sleep variability, and nocturnal sleep problems in toddlers: results from the GET UP! Study

OBJECTIVE

To explore the correlates of nocturnal sleep duration, nocturnal sleep variability, and nocturnal sleep problems in a sample of Australian toddlers.

METHODS

Participants were 173 toddlers (average age 19.7 ± 4.1 months) from the GET UP!

STUDY

Nocturnal sleep duration, nocturnal sleep variability, nap(s) and physical activity were measured using 24-h accelerometry (Actigraph GT3X+) over seven consecutive days. Nocturnal sleep problems were assessed using the Tayside Children's Sleep Questionnaire. Screen time was reported by the parents. Logistic regression models were used to examine the associations between potential correlates (ie, age, sex, socio-economic status, weight status, physical activity, screen time, nap(s), bedtimes, and wake-up times) and nocturnal sleep characteristics.

RESULTS

Older children were more likely to have greater sleep variability (OR: 1.97; 95% CI: 1.08-3.61). Less physical activity (OR: 2.38; 95% CI: 1.27-4.45), shorter nap(s) (OR: 2.42, 95% CI: 1.29-4.55), and later wake-up times (OR: 4.42; 95% CI: 2.32-8.42) were associated with higher odds of having longer nocturnal sleep duration. Late bedtimes were associated with shorter nocturnal sleep duration (OR: 0.09; 95% CI: 0.04-0.18) and with greater nocturnal sleep variability (OR: 1.97; 95% CI: 1.06-3.68). None of the potential correlates were associated with nocturnal sleep problems.

CONCLUSION

The present study identifies several correlates of nocturnal sleep duration (total physical activity, nap(s), bedtime, and wake-up time) and nocturnal sleep variability (age and bedtime), whereas no correlates were identified for nocturnal sleep problems. The association between late bedtimes and shorter nocturnal sleep duration and greater nocturnal variability suggests that these may be modifiable targets for future sleep interventions in early childhood.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12616000471482, 11/04/2016, retrospectively registered.

A longitudinal, within-person investigation of the association between the P3 ERP component and externalizing behavior problems in young children

BACKGROUND

Externalizing problems, including aggression and conduct problems, are thought to involve impaired attentional capacities. Previous research suggests that the P3 event-related potential (ERP) component is an index of attentional processing, and diminished P3 amplitudes to infrequent stimuli have been shown to be associated with externalizing problems and attention-deficit/hyperactivity disorder (ADHD). However, the vast majority of this prior work has been cross-sectional and has not examined young children. The present study is the first investigation of whether within-individual changes in P3 amplitude predict changes in externalizing problems, providing a stronger test of developmental process.

METHOD

Participants included a community sample of children (N = 153) followed longitudinally at 30, 36, and 42 months of age. Children completed an oddball task while ERP data were recorded. Parents rated their children's aggression and ADHD symptoms.

RESULTS

Children's within-individual changes in the P3 amplitude predicted concomitant within-child changes in their aggression such that smaller P3 amplitudes (relative to a child's own mean) were associated with more aggression symptoms. However, changes in P3 amplitudes were not significantly associated with ADHD symptoms.

CONCLUSIONS

Findings suggest that the P3 may play a role in development of aggression, but do not support the notion that the P3 plays a role in development of early ADHD symptoms.

Influence of sleep on developing brain functions and structures in children and adolescents: A systematic review

This systematic review examined the associations between sleep and brain functions and structures in children and adolescents aged 1-17 ys. Included studies (n = 24) were peer-reviewed and met the a priori determined population (apparently healthy children and adolescents aged 1 y to 17 ys), intervention/exposure/comparator (various sleep characteristics including duration, architecture, quality, timing), and outcome criteria (brain functions and/or brain structures, excluding cognitive function outcomes). Collectively, the reviewed studies report some relationships between inadequate sleep and resultant differences in brain functions or structures. Although the research presented supports and offers more insight into the importance of sleep for the developing brain of children and adolescents, no firm conclusions that apply broadly may be drawn from these results, particularly because of the diversity of the sleep variables and outcomes. However, it is clear that sleeping habits in the pediatric population should be prioritized. Health care providers should continue to recommend healthy sleep practices and adequate time for sleep, as they are essential for overall health, including brain health.

Systematic review of the relationships between sleep duration and health indicators in the early years (0-4 years)

Background

The objective of this systematic review was to examine for the first time the associations between sleep duration and a broad range of health indicators in children aged 0 to 4 years.

Methods

Electronic databases were searched with no limits on date or study design. Included studies (published in English or French) were peer-reviewed and met the a priori determined population (apparently healthy children aged 1 month to 4.99 years), intervention/exposure/comparator (various sleep durations), and outcome criteria (adiposity, emotional regulation, cognitive development, motor development, growth, cardiometabolic health, sedentary behaviour, physical activity, quality of life/well-being, and risks/injuries). The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. Due to high levels of heterogeneity across studies, narrative syntheses were employed.

Results

A total of 69 articles/studies (62 unique samples) met inclusion criteria. Data across studies included 148,524 unique participants from 23 countries. The study designs were randomized trials (n = 3), non-randomized interventions (n = 1), longitudinal studies (n = 16), cross-sectional studies (n = 42), or longitudinal studies that also reported cross-sectional analyses (n = 7). Sleep duration was assessed by parental report in 70% of studies (n = 48) and was measured objectively (or both objectively and subjectively) in 30% of studies (n = 21). Overall, shorter sleep duration was associated with higher adiposity (20/31 studies), poorer emotional regulation (13/25 studies), impaired growth (2/2 studies), more screen time (5/5 studies), and higher risk of injuries (2/3 studies). The evidence related to cognitive development, motor development, physical activity, and quality of life/well-being was less clear, with no indicator showing consistent associations. No studies examined the association between sleep duration and cardiometabolic biomarkers in children aged 0 to 4 years. The quality of evidence ranged from “very low” to “high” across study designs and health indicators.

Conclusions

Despite important limitations in the available evidence, longer sleep duration was generally associated with better body composition, emotional regulation, and growth in children aged 0 to 4 years. Shorter sleep duration was also associated with longer screen time use and more injuries. Better-quality studies with stronger research designs that can provide information on dose-response relationships are needed to inform contemporary sleep duration recommendations.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4850-2) contains supplementary material, which is available to authorized users.

Intraindividual variability of sleep/wake patterns in relation to child and adolescent functioning: A systematic review

Substantial research attention has been devoted to understanding the importance and impact of sleep in children and adolescents. Traditionally, this has focused on mean sleep variables (e.g., a child's "typical" or average sleep duration), yet research increasingly suggests that intraindividual variability (IIV) of sleep/wake patterns (sometimes referred to as sleep variability or night-to-night variability) regularly occurs and may have implications for adjustment. A systematic search of five electronic databases identified 52 empirical studies published between 2000 and 2015 that examined correlates of sleep IIV in children and adolescents, with a recent increase in the publication rate of such studies. Identified studies were often atheoretical and included post hoc analyses, though IIV in select aspects of sleep does appear to be associated with increasing age/pubertal status, non-White race, physical and neurodevelopmental conditions (e.g., attention-deficit/hyperactivity disorder; autism), psychopathology symptoms (e.g., anxiety, depression, inattention), body weight, stress, aspects of cognitive functioning, and poorer sleep functioning/habits. The limited intervention work examining sleep IIV in adolescents is promising, though studies are needed using more rigorous intervention designs. Clinical sleep recommendations may not only need to address overall sleep duration and sleep habits but also the stability of sleep duration and timing. It will be important for future research examining sleep IIV in children and adolescents to use a developmental framework in advancing theory pertaining to the causes, mechanisms, moderators, and outcomes of sleep IIV in youth, and a conceptual model is proposed to help guide such efforts.