Mapping cortical rhythms to infant behavioral tendencies via baseline EEG and parent‐report

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.

Associations between EEG power and coherence with cognition and early precursors of speech and language development across the first months of life

The neural processes underpinning cognition and language development in infancy are of great interest. We investigated EEG power and coherence in infancy, as a reflection of underlying cortical function of single brain region and cross-region connectivity, and their relations to cognition and early precursors of speech and language development. EEG recordings were longitudinally collected from 21 infants with typical development between approximately 1 and 7 months. We investigated relative band power at 3-6Hz and 6-9Hz and EEG coherence of these frequency ranges at 25 electrode pairs that cover key brain regions. A correlation analysis was performed to assess the relationship between EEG measurements across frequency bands and brain regions and raw Bayley cognitive and language developmental scores. In the first months of life, relative band power is not correlated with cognitive and language scales. However, 3-6Hz coherence is negatively correlated with receptive language scores between frontoparietal regions, and 6-9Hz coherence is negatively correlated with expressive language scores between frontoparietal regions. The results from this preliminary study contribute to the existing literature on the relationship between electrophysiological development, cognition, and early speech precursors in this age group. Future work should create norm references of early development in these domains that can be compared with infants at risk for neurodevelopmental disabilities.

Bursting with Potential: How Sensorimotor Beta Bursts Develop from Infancy to Adulthood

Beta activity is thought to play a critical role in sensorimotor processes. However, little is known about how activity in this frequency band develops. Here, we investigated the developmental trajectory of sensorimotor beta activity from infancy to adulthood. We recorded EEG from 9-month-old, 12-month-old, and adult humans (male and female) while they observed and executed grasping movements. We analyzed "beta burst" activity using a novel method that combines time-frequency decomposition and principal component analysis. We then examined the changes in burst rate and waveform motifs along the selected principal components. Our results reveal systematic changes in beta activity during action execution across development. We found a decrease in beta burst rate during movement execution in all age groups, with the greatest decrease observed in adults. Additionally, we identified three principal components that defined waveform motifs that systematically changed throughout the trial. We found that bursts with waveform shapes closer to the median waveform were not rate-modulated, whereas those with waveform shapes further from the median were differentially rate-modulated. Interestingly, the decrease in the rate of certain burst motifs occurred earlier during movement and was more lateralized in adults than in infants, suggesting that the rate modulation of specific types of beta bursts becomes increasingly refined with age.SIGNIFICANCE STATEMENT We demonstrate that, like in adults, sensorimotor beta activity in infants during reaching and grasping movements occurs in bursts, not oscillations like thought traditionally. Furthermore, different beta waveform shapes were differentially modulated with age, including more lateralization in adults. Aberrant beta activity characterizes various developmental disorders and motor difficulties linked to early brain injury, so looking at burst waveform shape could provide more sensitivity for early identification and treatment of affected individuals before any behavioral symptoms emerge. More generally, comparison of beta burst activity in typical versus atypical motor development will also be instrumental in teasing apart the mechanistic functional roles of different types of beta bursts.

Associations between EEG power and coherence and cognitive and language development across the first months of life

The neural processes underpinning cognition and language development in infancy are of great interest. We investigated EEG power and coherence in infancy, as a reflection of underlying cortical function of single brain region and cross-region connectivity, and their relations to cognition and language development. EEG recordings were longitudinally collected from 21 infants with typical development between 1 and 7 months. We investigated relative band power at theta (3-6Hz) and alpha (6-9Hz) and EEG coherence of these frequency bands at 25 electrode pairs that cover key brain regions. A correlation analysis was performed to assess the relationship between EEG measurements (frequency bands and brain regions) and raw Bayley cognitive and language developmental scores. In the first months of life, relative band power is not correlated with changes in cognitive and language scales. However, theta coherence is negatively correlated with receptive language scores between frontoparietal regions, and alpha coherence is negatively correlated with expressive language scores between frontoparietal regions. The results from this preliminary study are the first steps in identifying potential biomarkers of early cognitive and language development. In future work, we will confirm norm references of early cognitive and language development that can be compared with infants at risk for neurodevelopmental disabilities.

Does the Frontal Brain Electrical Activity Mediate the Effect of Home Executive Function Environment and Screen Time on Children's Executive Function?

Executive functions play an important role in various developmental aspects of children; however, environmental factors influencing individual differences in children's executive function and their neural substructures, particularly in middle childhood, are rarely investigated. Therefore, the current study aimed to investigate the relationship between the home executive function environment (HEFE) and screen time with the executive function of children aged 8-12 years by employing the mediating variables of alpha, beta, and theta waves. The parents of 133 normal children completed Barkley Deficits in Executive Functioning, HEFE, and Screen Time Scales. Alpha, beta, and theta brain waves were also measured. Data were examined using correlational and path analysis. The results suggested a positive and significant relationship between home executive functions and the executive functions of children. Furthermore, the results indicated an inverse and significant relationship between screen time and executive function. The results also proved the mediating role of alpha, beta, and theta brain waves in the relationship between screen time and the children's executive function. Environmental factors (such as home environment and screen time) affect the function of brain waves and, thus, the daily executive function of children.

Effects of Early Nutrition Factors on Baseline Neurodevelopment during the First 6 Months of Life: An EEG Study

Throughout infancy, the brain undergoes rapid changes in structure and function that are sensitive to environmental influences, such as diet. Breastfed (BF) infants score higher on cognitive tests throughout infancy and into adolescence than formula fed (FF) infants, and these differences in neurocognitive development are reflected in higher concentrations of white and grey matter as measured by MRI. To further explore the effect diet has on cognitive development, electroencephalography (EEG) is used as a direct measure of neuronal activity and to assess specific frequency bands associated with cognitive processes. Task-free baseline EEGs were collected from infants fed with human milk (BF), dairy-based formula (MF), or soy-based formula (SF) at 2, 3, 4, 5, and 6 months of age to explore differences in frequency bands in both sensor and source space. Significant global differences in sensor space were seen in beta and gamma bands between BF and SF groups at ages 2 and 6 months, and these differences were further observed through volumetric modeling in source space. We conclude that BF infants exhibit earlier brain maturation reflected in greater power spectral density in these frequency bands.

Comparing executive functions in children with attention deficit hyperactivity disorder with or without reading disability: A resting-state EEG study

INTRODUCTION

As numerous studies have shown, executive dysfunction is the main impairment in attention-deficit/hyperactivity disorder. According to recent neuroimaging studies, the frontoparietal coherence plays a key role in overall cognitive functions. Therefore, the aim of this study was to compare executive functions during resting-state EEG by monitoring brain connectivity (coherence) patterns in children with attention deficit hyperactivity disorder (ADHD) with or without reading disability (RD).

METHODS

The statistical sample of the study consisted of 32 children with ADHD aged between 8 and 12 years old with or without specific RD. Each group consisted of 11 boys and 5 girls that were matched on chronological age and gender. EEG was recorded during eyes-opened condition and brain connectivity within and between frontal and parietal regions was analyzed within theta, alpha, and beta bands.

RESULTS

The results revealed that across the frontal regions, the comorbid group showed a significant reduction in the left intrahemispheric coherence in the alpha and beta bands. The ADHD-alone group exhibited increased theta and decreased alpha and beta coherence in frontal regions. In the frontoparietal regions, children in the comorbid group showed lower coherence between frontal and parietal networks compared to children without comorbid RD.

CONCLUSION

The findings indicate that brain connectivity (coherence) patterns of children with ADHD with comorbid RD were more abnormal and lend support to more disrupted cortical connectivity in the comorbid group. Thus, these findings can be a useful marker for better recognizing ADHD and comorbid disabilities.

Habitual night waking associates with dynamics of waking cortical theta power in infancy

The implications of the substantial individual differences in infant sleep for early brain development remain unclear. Here, we examined whether night sleep quality relates to daytime brain activity, operationalized through measures of EEG theta power and its dynamic modulation, which have been previously linked to later cognitive development. For this longitudinal study, 76 typically developing infants were studied (age: 4-14 months, 166 individual study visits) over the course of 6 months with one, two, three, or four lab visits. Habitual sleep was measured with a 7-day sleep diary and actigraphy, and the Brief Infant Sleep Questionnaire. Twenty-channel EEG was recorded while infants watched multiple rounds of videos of women singing nursery rhymes; oscillatory power in the theta band was extracted. Key metrics were average theta across stimuli and the slope of change in theta within the first novel movie. Both objective and subjective sleep assessment methods showed a relationship between more night waking and higher overall theta power and reduced dynamic modulation of theta over the course of the novel video stimuli. These results may indicate altered learning and consolidation in infants with more disrupted night sleep, which may have implications for cognitive development.

Self-regulation and frontal EEG alpha activity during infancy and early childhood: A multilevel meta-analysis

Integrating behavioral and neurophysiological measures has created new and advanced ways to understand the development of self-regulation. Electroencephalography (EEG) has been used to examine how self-regulatory processes are related to frontal alpha power during infancy and early childhood. However, findings across previous studies have been inconsistent. To address this issue, the current meta-analysis synthesized all prior literature examining associations between individual differences in self-regulation and frontal EEG alpha power (baseline and/or task). In total, 23 studies consisting of 1275 participants between 1 month and 6 years of age were included, which yielded 149 effect sizes. Findings of the three-level meta-analytic model demonstrated a non-significant overall association between self-regulation and frontal alpha power. Yet, significant moderating effects were found for self-regulation construct (emotion regulation, effortful control, executive function), self-regulation measurement (behavioral task, computer assessment, lab observation, questionnaire), and children's mean age. Self-regulation was only significantly correlated with frontal alpha power when studies focused on the executive functioning construct. Moreover, the use of behavioral tasks or questionnaires and a higher mean age of the children resulted in small but significant effect size estimates. Higher frontal alpha power values were related to higher order top-down mechanisms of self-regulation, indicating that these mechanisms might become stronger when the frontal cortex is sufficiently developed. The findings of the current meta-analysis highlight the importance of longitudinal analyses and multimethod approaches in future work to reach a more comprehensive understanding of the role of frontal EEG alpha activity in the etiology of individual differences in early self-regulation. RESEARCH HIGHLIGHTS: The first meta-analysis of individual differences in self-regulation and frontal EEG alpha power during infancy and early childhood demonstrated a non-significant overall association. Moderation analyses revealed that variations in frontal alpha power were significantly associated with executive function, but not with effortful control and emotion regulation. Frontal alpha power was related to variations in self-regulation when measured by behavioral tasks and questionnaires, but not via computer assessments and lab observations. The association between individual differences in self-regulation and frontal alpha power becomes significantly stronger with age.

Sex-specific associations among infant food and atopic sensitizations and infant neurodevelopment

INTRODUCTION

Food sensitization is a first and strong indicator of immune deviation in the progression to other allergic conditions. Sensitization to food or other allergens and related inflammation during critical windows of infant development may adversely affect neurodevelopmental milestones. However, additional research is needed to test this association further.

METHODS

Associations between atopic (any food or aeroallergen) or food sensitization (specific to egg, soybean, peanut, and milk) at age 1 year and neurodevelopment up to 2 years of age were evaluated in the national CHILD Cohort Study, with a secondary aim examining whether these associations were sex-specific. Food and atopic sensitization were assessed by skin prick tests (SPT) in 1-year-old infants, with neurodevelopment assessed using the cognitive, language, motor, and social-emotional subscales of the Bayley Scales of Infant Development (BSID-III) administered at 1 and 2 years of age.

RESULTS

Atopic sensitization was present among 16.4% of infants, while 13.4% had food sensitizations. Only socioemotional scores reached statistical significance among the four BSID-III domains. Both atopic and food sensitization at 1 year of age was associated with lower social-emotional scores, independent of the infant's ethnicity. These findings were sex-specific and only observed among boys, among whom social-emotional scores were lowered by 5 points if atopic sensitization was present (-5.22 [95% CI: -9.96, -0.47], p = 0.03) or if food sensitization was present (-4.85 [95% CI: -9.82,0.11], p = 0.06). Similar results were observed using the standard SPT cut-off of ≥3 mm - for atopic sensitization (-5.17 [95% CI: -11.14, -0.80], p = 0.09) and for food sensitization (-4.61 [95% CI: -10.96, 1.74], p = 0.15).

CONCLUSION

In our study of term infants, we found an inverse, cross-sectional association between atopic and food sensitization status and social-emotional development scores in male children but not female children.

Detection and Analysis of Cortical Beta Bursts in Developmental EEG Data

Developmental EEG research often involves analyzing signals within various frequency bands, based on the assumption that these signals represent oscillatory neural activity. However, growing evidence suggests that certain frequency bands are dominated by transient burst events in single trials rather than sustained oscillations. This is especially true for the beta band, with adult ‘beta burst’ timing a better predictor of motor behavior than slow changes in average beta amplitude. No developmental research thus far has looked at beta bursts, with techniques used to investigate frequency-specific activity structure rarely even applied to such data. Therefore, we aimed to: i) provide a tutorial for developmental EEG researchers on the application of methods for evaluating the rhythmic versus transient nature of frequency-specific activity; and ii) use these techniques to investigate the existence of sensorimotor beta bursts in infants. We found that beta activity in 12-month-olds did occur in bursts, however differences were also revealed in terms of duration, amplitude, and rate during grasping compared to adults. Application of the techniques illustrated here will be critical for clarifying the functional roles of frequency-specific activity across early development, including the role of beta activity in motor processing and its contribution to differing developmental motor trajectories.

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Transient bursts rather than oscillations dominate sensorimotor beta activity

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Lagged coherence indicates the rhythmicity of a signal

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The p-episode method can be used to identify beta bursts in developmental EEG data

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Infant sensorimotor beta has a lower peak frequency than adults and consists of longer duration, higher amplitude bursts

Context matters: Cortical rhythms in infants across baseline and play

This study uses electroencephalography (EEG) to examine infants' cortical activity during baseline while they watched a dynamic audiovisual display and while engaged in play with an object and parent. Fifty-five 6- to 12-month-old infants participated in both baseline and play with their mother. We hypothesized that the baseline task recruits relatively more exogenous attention due to the dynamic audiovisual task, while the play task recruits relatively more endogenous attention when exploring the toy. We expected higher frontal theta and alpha power during play, reflecting higher endogenous control of attention compared to the baseline task. We expected the faster rhythms, beta and gamma, to have higher power during baseline at frontal locations, reflecting the salient attention-grabbing (exogenous) attributes of the baseline task in comparison to play. We also examined changes in parietal power between contexts. Our results were consistent with the expectations. Theta (3-6 Hz) and alpha (6-9 Hz) power were higher at frontal sites (Fp1/Fp2) during play relative to baseline. Beta (9-30 Hz) and gamma (30-50 Hz) power were higher at frontal (Fp1/Fp2) and frontal medial sites (F3/F4) during baseline relative to play. Alpha power was higher during baseline at frontal medial sites (F3/F4) relative to play. Beta and gamma power was higher during play at parietal sites (P3/P4). The results are discussed in terms of the potential role of different cortical rhythms over the scalp as they respond to relative endogenous and exogenous attentional demands.

Play with Mom: Insights into Regulatory Processes at Work during Baseline and Parent-infant Play

Frontal alpha asymmetry (FAA) is a neural correlate of approach and avoidance motivational processes. This study examined the shift in FAA from baseline to play, associations to parent-reported regulatory abilities, and parent and infant behaviors during play. Infants exhibited greater left frontal alpha activity (more approach) during baseline relative to play. Shifts in FAA toward greater left frontal alpha activity (more approach) from baseline to play were associated with parent ratings of infants' regulatory behaviors and object exploration exhibited during play. These results highlight ongoing regulatory processes involved in positively valenced tasks typical in infants' daily life.

Development and validation of the Mindful Parenting in Infancy Scale (MPIS)

Although mindfulness in parenting has been recognized as important for some time, there is a dearth of measurement tools, especially for caregivers of infants. Two studies were conducted: (1) developing and providing an initial psychometric evaluation of the Mindful Parenting in Infancy Scale (MPIS) and (2) reproducing initial findings with an independent sample of infants and caregivers. In Study 1, 37 caregivers of infants (3-12 months of age) responded to MPIS, providing indicators of parenting stress and infant temperament. Study 2 caregivers (N = 57) responded to identical measures, with infant electroencephalogram (EEG) recorded during the Still Face Procedure, along with a baseline condition. Study 1 results indicated good internal consistency, with Study 2 providing additional support for reliability. Correlations with parenting stress markers were also significant across both investigations, indicative of greater stress with lower levels of mindfulness. A number of correlations with temperament scores were also significant, and in the hypothesized direction, across both studies. Importantly, the MPIS score was predictive of infant frontal EEG asymmetry in a path model examined in the context of Study 2. Thus, the present investigation provides support for MPIS as a promising brief measurement tool based on results obtained with two independent samples.

The relationship of resting-state EEG oscillations to executive functions in middle childhood

Executive functions (EFs) play important roles in children's development, but their neural mechanisms are rarely investigated, especially for the different components of EFs in middle childhood. Therefore, this study aimed to explore the links between resting-state EEG in the frontal scalp region and EFs in children aged 7-9 years. Fifty-nine typically developing children from the second and third grades performed two core EF tasks, i.e., inhibition and working memory, and a high-level EF task, i.e., planning, followed by the recording of EEG signals during eyes-open and eyes-closed resting states. The results showed that distinct EEG activities in the frontal scalp region predicted different EF components. More specifically, after controlling for age and verbal ability, alpha to theta power ratio (ATR) and beta to theta power ratio (BTR) during the eyes-open resting state positively predicted inhibition, and beta to theta power ratio (BTR) during the eyes-open resting state positively predicted planning. However, we did not find any EEG features related to working memory. Our results contributed to the understanding of inter-individual differences in EFs and provided insights into the regulation of corresponding EEG activities through EEG neurofeedback for enhancing children's EFs.

Dynamics of frontal alpha asymmetry in mother-infant dyads: Insights from the Still Face Paradigm

The parent-infant dynamic has a foundational role in emotion regulation development. Electroencephalography (EEG) hyperscanning from mother-infant dyads can provide an unprecedented window into inter-brain dynamics during the parent-infant exchange. This potential depends on the feasibility of hyperscanning with dyads in emotionally taxing contexts. We sought to demonstrate feasibility of hyperscanning from 10 mother-infant dyads during the Still Face Procedure (SFP). We measured frontal alpha asymmetry (FAA) to elucidate ongoing regulatory dynamics and considered maternal caregiving quality as a window into dyads' history. Results showed dyads exhibited a rightward shift in FAA over the course of SFP, indicating growing negative emotionality and desire to withdraw. Results also showed growing variability in FAA for infants over the course of SFP, indicating less active emotional control as stress ensued. Variability was especially low for mothers during periods when asked to be emotionally unavailable, suggesting active control to match the task demands. Dyads with a more responsive mother exhibited higher (more left) FAA relative to dyads with a less responsive mother, which might reflect a more positive emotional experience overall. We raise important methodological and theoretical questions that hyperscanning during SFP can address, such as the developmental origins of trait-like self-regulatory dispositions.