Resting brain activity in early childhood predicts IQ at 18 years

Electroencephalogram activity related to psychopathological and neuropsychological symptoms in institutionalised minors: a systematic review

OBJECTIVE

This systematic review aims to update the current evidence on the effects of institutionalisation in minors living in residential care homes, specifically focusing on alterations in neuronal systems and their association with psychopathological and neuropsychological outcomes.

METHODS

Searches were conducted in the Web of Science, Scopus, PubMed, and Google Scholar databases, following PRISMA methodology for peer-reviewed empirical articles. The final selection comprised 10 studies that met the inclusion criteria: (1) published articles with quantitative data, (2) aimed at observing the relationship between psychological and neuropsychological symptoms and the electroencephalogram (EEG) activity in institutionalised children, (3) published between 2016 and 2023, and (4) examining institutionalised minors in residential care homes.

RESULTS

The articles show that these children exhibit general immaturity in EEG patterns, with a predominance of slow waves (primarily in the theta band). They also demonstrate poorer performance in executive functions (e.g. working memory, inhibition, and processing speed) and cognitive processes, along with a higher risk of externalising problems. However, current evidence does not allow definitive conclusions on whether early EEG abnormalities predict long-term neuropsychological deficits, despite data showing associations between EEG changes and certain cognitive dysfunctions at the time of evaluation.

CONCLUSION

The reviewed evidence suggests that EEG alterations in institutionalised minors are linked to executive dysfunction and increased psychopathological risk. These findings highlight the value of EEG in identifying at-risk children and inform the design of preventive interventions. Longitudinal studies are needed to clarify causal relationships.

A hierarchical model of early brain functional network development

Functional brain networks emerge prenatally, grow interactively during the first years of life, and optimize both within-network topology and between-network interactions as individuals age. This review summarizes research that has characterized this process over the past two decades, and aims to link functional network growth with emerging behaviors, thereby developing a more holistic understanding of the developing brain and behavior from a functional network perspective. This synthesis suggests that the development of the brain's functional networks follows an overlapping hierarchy, progressing from primary sensory/motor to socioemotional-centered development and finally to higher-order cognitive/executive control networks. Risk-related alterations, resilience factors, treatment effects, and novel therapeutic opportunities are also discussed to encourage the consideration of future imaging-assisted methods for identifying risks and interventions.

Oscillatory But Not Aperiodic Frontal Brain Activity Predicts the Development of Executive Control From Infancy to Toddlerhood

Executive control (EC) emerges in the first year of life, with the ability to inhibit prepotent responses (inhibitory control [IC]) and to flexibly readapt (cognitive flexibility [CF]) steadily improving. Simultaneously, electrophysiological brain activity undergoes profound reconfiguration, which has been linked to individual variability in EC. However, most studies exploring this relationship have used relative/absolute power and tasks that combine different executive processes. In addition, brain activity conflates aperiodic and oscillatory activity, which hinders the interpretation of the relationship between power and cognition. In the current study, we used the Early Childhood Inhibitory Touchscreen Task (ECITT) to examine the development of EC skills from 9 to 16 months in a longitudinal sample, and related performance of the task to resting-state EEG (rs-EEG) power, separating oscillatory and aperiodic activity. Our results showed improvement in IC but not in CF with age. In addition, alpha and theta oscillatory activity were concurrent (9-mo.) and longitudinal predictors of CF in toddlerhood, whereas the aperiodic exponent of the EEG signal did not contribute to EC. These findings demonstrate the relevance of oscillatory brain activity for cognitive development and provide an early brain marker for the early development of EC.

Heterogeneity in pediatric resting EEG data processing and analysis: A state of the field

Developmental, resting electroencephalography (EEG) is gaining rapid popularity with implementation in large-scale studies as well as a recent WHO report naming resting EEG as a gold standard measure of brain health. With an increased interest in resting EEG as a potential biomarker for neurocognition, it is paramount that resting EEG findings are reliable and reproducible. One of the major threats to replicability and reproducibility stems from variations in preprocessing and analysis. One of the primary challenges facing the field of developmental EEG is that it can be challenging to acquire data from infants and children, which commonly makes data cleaning and analysis difficult and unstandardized. The goal of the present manuscript is to take a state of the field of the methods experts in resting EEG report they would use to clean and analyze a hypothetical data set. Here we report on the responses of 66 self-identified experts in developmental psychophysiology, none of which submitted identical preregistrations. As expected, there were areas of more and less consensus, but ultimately, we believe our findings highlight opportunities for core methodological work and field-level efforts to establish consensus.

Physical and neurophysiological maturation associated with ADHD among previously institutionalized children: a randomized controlled trial

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental outcome among children with a history of early institutional care. Prior research on institutionalized children suggested that accelerated physical growth in childhood is a risk factor for ADHD outcomes.

METHODS

The current study examined physical and neurophysiological growth trajectories among institutionalized children randomized to foster care treatment (n = 59) or care as usual (n = 54), and never institutionalized children (n = 64) enrolled in the Bucharest Early Intervention Project (NCT00747396, clinicaltrials.gov). Participants completed physical and electroencephalography (EEG) assessments at six time points from infancy through adolescence, as well as structured diagnostic interviews at the 54-month and 12-year time points. A series of multilevel growth models and cross-lagged path models were estimated to examine associations among physical and neurophysiological maturation, treatment group, age of foster care placement, and ADHD diagnostic outcomes.

RESULTS

Twenty-seven percent of the institutionalized children met research criteria for ADHD at one or both time points. Slowed, prolonged growth of height and head circumference were associated with both ADHD and delayed foster care placement. Placement in foster care versus care as usual, but not ADHD, was associated with maturation of the peak alpha frequency. Among children randomized to foster care, average theta-beta ratio was lower among those with ADHD. There was no evidence that rapid physical maturation led to atypical cortical activity.

CONCLUSIONS

Delayed, prolonged physical growth and atypical neurophysiology from infancy through adolescence is associated with ADHD among institutionalized children, over and above the protective effects of foster care.

EEG activation in preschool children: Characteristics and predictive value for current and future mental health status

BACKGROUND

Previous research has characterised EEG changes associated with resting activation in primary school children and adults, while task-related activation has only been considered in adults. The current study characterises physiological activation in preschool children and examines the potential value of activation indices for predicting mental health status at two time points.

AIMS

To investigate how resting activation and task-related activation are represented in 4- to 5-year-old preschool children and examine if these activation indices can predict current and future mental health status.

METHODS AND PROCEDURES

Frontal EEG was recorded from 81 preschool children during eyes-closed resting, eyes-open resting, and an inhibitory control task to allow calculation of activation indices. The Child Behaviour Checklist was completed by the child's parent at this time, and again 6-8 months later after the child's transition to kindergarten.

OUTCOMES AND RESULTS

Resting activation was represented by reductions in frontal delta, theta, and alpha power in the eyes-open compared to eyes-closed condition, and an increase in frontal beta power. Task-related activation was represented by increases in frontal delta, theta, and alpha power and a decrease in beta power. Frontal delta and theta task-related activation significantly predicted externalising behaviours in both preschool and kindergarten, with stronger prediction in kindergarten.

CONCLUSIONS AND IMPLICATIONS

This study characterised resting and task-related activation in preschool children, and reported similar effects to those found in older children and adults for resting activation, with novel effects for task-related activation. As task-related activation indices were predictive of externalising behaviours in both preschool and kindergarten, these results have implications for early identification of children who experience externalising behavioural problems across the transition to school period. WHAT DOES THIS STUDY ADD?: This study provides new data on how the fundamental physiological processes of resting and task-related activation, both of which are theorised to contribute to "upstream" processes such as executive functions and broader behaviour, are represented in the frontal EEG of preschool aged children. We also learn that the top-down task-related activation indices for delta and theta activity were predictive of current mental health status and future status after the transition to kindergarten, while the bottom-up resting activation indices were not.

Linking caregiving quality during infancy to brain activity in early childhood and later executive function

There is no relationship more vital than the one a child shares with their primary caregivers early in development. Yet many children worldwide are raised in settings that lack the warmth, connection, and stimulation provided by a responsive primary caregiver. In this study, we used data from the Bucharest Early Intervention Project (BEIP), a longitudinal study of institutionally-reared and family-reared children, to test how caregiving quality during infancy is associated with average EEG power over the first 3.5 years of life in alpha, beta, and theta frequency bands, and associations with later executive function (EF) at age 8 years. The sample comprised 189 children (129 institutionally-reared; 60 family-reared) who contributed data on observed caregiving quality during infancy (baseline; average age of 22 months), resting EEG power at baseline, 30, and 42 months, and performance-based data on a series of EF tasks at 8 years. Using Bayesian estimation, observed caregiving quality at baseline was marginally linked with higher average alpha and beta power, and lower theta power, from baseline to 42 months. In turn, higher average beta power and lower average theta power were marginally associated with higher EF at 8 years. In indirect effects models, higher caregiving quality at baseline was associated with higher EF at 8 years, with a marginal indirect effect through average theta power from baseline to 42 months. Variation in the quality of the early caregiving environment may be associated with later executive function, which is partially underpinned by individual differences in brain activity during early childhood. RESEARCH HIGHLIGHTS: Examined associations between caregiving quality during infancy, brain activity during early childhood, and executive function during mid-childhood in sample of never-institutionalized and institutionally-reared children. Significant associations between higher quality caregiving during infancy and higher executive function during middle childhood. Marginal associations between caregiving quality during infancy and brain activity during early childhood. Marginal associations between brain activity during early childhood and executive function during mid-childhood.

Early Family Experiences and Neural Activity in Rural Pakistani Children: The Differential Role of Gender

Adversity within low- and middle-income countries (LMICs) poses severe threats to neurocognitive development, which can be partially mitigated by high-quality early family experiences. Specifically, maternal scaffolding and home stimulation can buffer cognitive development in LMIC, possibly by protecting underlying neural functioning. However, the association between family experiences and neural activity remains largely unexplored in LMIC contexts. This study explored the relation of early family experiences to later cognitive skills and absolute gamma power (21-45 Hz), a neural marker linked to higher-order cognitive skills. Drawing data from the PEDS trial, a longitudinal study in rural Pakistan, we examined maternal scaffolding at 24 months and home stimulation quality at 18 months as predictors of verbal IQ, executive functions, and absolute gamma at 48 months for 105 mother-child dyads (52 girls). Maternal scaffolding interacted with gender to predict absolute gamma power, such that higher maternal scaffolding was related to higher gamma more strongly for girls. Maternal scaffolding also interacted with absolute gamma to predict executive functions, such that higher gamma was related to better executive functions only when maternal scaffolding was average to high. Individual differences in early family experiences may partially buffer the neural underpinnings of cognitive skills from adversity in LMIC.

Theta activity and cognitive functioning: Integrating evidence from resting-state and task-related developmental electroencephalography (EEG) research

The theta band is one of the most prominent frequency bands in the electroencephalography (EEG) power spectrum and presents an interesting paradox: while elevated theta power during resting state is linked to lower cognitive abilities in children and adolescents, increased theta power during cognitive tasks is associated with higher cognitive performance. Why does theta power, measured during resting state versus cognitive tasks, show differential correlations with cognitive functioning? This review provides an integrated account of the functional correlates of theta across different contexts. We first present evidence that higher theta power during resting state is correlated with lower executive functioning, attentional abilities, language skills, and IQ. Next, we review research showing that theta power increases during memory, attention, and cognitive control, and that higher theta power during these processes is correlated with better performance. Finally, we discuss potential explanations for the differential correlations between resting/task-related theta and cognitive functioning, and offer suggestions for future research in this area.

The Necessity of Taking Culture and Context into Account When Studying the Relationship between Socioeconomic Status and Brain Development

Decades of research has revealed a relationship between childhood socioeconomic status (SES) and brain development at the structural and functional levels. Of particular note is the distinction between income and maternal education, two highly correlated factors which seem to influence brain development through distinct pathways. Specifically, while a families' income-to-needs ratio is linked with physiological stress and household chaos, caregiver education influences the day-to-day language environment a child is exposed to. Variability in either one of these environmental experiences is related to subsequent brain development. While this work has the potential to inform public policies in a way that benefits children, it can also oversimplify complex factors, unjustly blame low-SES parents, and perpetuate a harmful deficit perspective. To counteract these shortcomings, researchers must consider sociodemographic differences in the broader cultural context that underlie SES-based differences in brain development. This review aims to address these issues by (a) identifying how sociodemographic mechanisms associated with SES influence the day-to-day experiences of children, in turn, impacting brain development, while (b) considering the broader cultural contexts that may differentially impact this relationship.

Associations between maternal stress and infant resting brain activity among families residing in poverty in the U.S

Growing evidence suggests that maternal experiences of stress shape children's functional brain activity in the first years of life. Individuals living in poverty are more likely to experience stress from a variety of sources. However, it is unclear how stress is related to resting brain activity among children born into poverty. The present study examines whether infants born into households experiencing poverty show differences in brain activity associated with maternal reports of experiencing stress. The analytic sample comprised 247 mother-infant dyads who completed maternal questionnaires characterizing stress, and for whom recordings of infant resting brain activity were obtained at 1 year of age (M=12.93 months, SD=1.66; 50% female). Mothers (40% Black, non-Hispanic, 40% Hispanic, 12% White, non-Hispanic) who reported higher stress had infants who showed more resting brain activity in the lower end of the frequency spectrum (relative theta power) and less resting brain activity in the middle range of the frequency spectrum (relative alpha power). While statistically detectable at the whole-brain level, follow-up exploratory analyses revealed that these effects were most apparent in electrodes over frontal and parietal regions of the brain. These findings held after adjusting for a variety of potentially confounding variables. Altogether, the present study suggests that, among families experiencing low economic resources, maternal reports of stress are associated with differences in patterns of infant resting brain activity during the first year of life.