Long-term stability of electroencephalographic asymmetry and power in 3 to 9 year-old children

Fearful temperament in middle childhood predicts adolescent attention bias and anxiety symptoms: The moderating role of frontal EEG asymmetry

The current study provided first analyses of the moderating effect of baseline-to-task frontal EEG asymmetry on the associations between 9-year fearful temperament and adolescent attention bias to threat as well as anxiety symptoms. Participants include a community sample of 122 children (60 boys, 62 girls; Mage = 14.66 years; Range = 11.82-18.13 years). Baseline-to-task frontal EEG asymmetry at age 9 moderated the relation between fearful temperament at age 9 and adolescent anxiety symptoms. Specifically, fearful temperament predicted adolescent anxiety symptoms when children showed greater right activation from baseline to an executive function task, but not greater left activation. Baseline-to-task frontal EEG asymmetry moderated the association between fearful temperament and sustained (i.e., stimulus onset asynchrony is 1250 ms) but not automatic attention bias (i.e., stimulus onset asynchrony is 500 ms). Children with greater left frontal activation from baseline to task more efficiently direct attention away from threat. Adolescent automatic attention bias to threat was related to concurrent anxiety symptoms. These findings illustrate the importance of considering frontal EEG asymmetry to shape how fearful children process threat and to influence their behavioral problems.

Adolescent Depressive Symptoms: The Role of Late Childhood Frontal EEG Asymmetry, Executive Function, and Adolescent Cognitive Reappraisal

Cognitive reappraisal is adaptive for decreasing symptoms of depression; however, a gap in the research is understanding the childhood processes that contribute to cognitive reappraisal in adolescence. This study examined executive function and frontal electroencephalogram (EEG) asymmetry during late childhood as predictors of adolescent cognitive reappraisal and depressive symptoms. Data were from 123 participants in late childhood (age 10) and adolescence (age 14.5). A moderated mediation model was fit to the data to examine frontal EEG asymmetry as a moderator in the relation between late childhood inhibitory control and adolescent cognitive reappraisal as well as adolescent cognitive reappraisal and adolescent depressive symptoms. Results indicated lower inhibitory control was associated with lower cognitive reappraisal when children had right frontal EEG asymmetry. Lower cognitive reappraisal in turn was associated with higher depressive symptoms for children with right frontal EEG asymmetry. Working memory and cognitive flexibility were also examined but were not significant indicators. Results suggest the potential for targeting inhibitory control and cognitive reappraisal to diminish depressive symptoms particularly among adolescents with right frontal EEG asymmetry.

Developmental trajectory of MEG resting-state oscillatory activity in children and adolescents: a longitudinal reliability study

Neural oscillations may be sensitive to aspects of brain maturation such as myelination and synaptic density changes. Better characterization of developmental trajectories and reliability is necessary for understanding typical and atypical neurodevelopment. Here, we examined reliability in 110 typically developing children and adolescents (aged 9-17 years) across 2.25 years. From 10 min of magnetoencephalography resting-state data, normalized source spectral power and intraclass correlation coefficients were calculated. We found sex-specific differences in global normalized power, with males showing age-related decreases in delta and theta, along with age-related increases in beta and gamma. Females had fewer significant age-related changes. Structural magnetic resonance imaging revealed that males had more total gray, subcortical gray, and cortical white matter volume. There were significant age-related changes in total gray matter volume with sex-specific and frequency-specific correlations to normalized power. In males, increased total gray matter volume correlated with increased theta and alpha, along with decreased gamma. Split-half reliability was excellent in all frequency bands and source regions. Test-retest reliability ranged from good (alpha) to fair (theta) to poor (remaining bands). While resting-state neural oscillations can have fingerprint-like quality in adults, we show here that neural oscillations continue to evolve in children and adolescents due to brain maturation and neurodevelopmental change.

Resting-state EEG Connectivity in Young Children with ADHD

Objective: Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent and impairing neurodevelopmental disorder. While early childhood is a crucial time for early intervention, it is characterized by instability of ADHD diagnosis. Neural correlates of ADHD have potential to improve diagnostic accuracy; however, minimal research has focused on early childhood. Research indicates that disrupted neural connectivity is associated with ADHD in older children. Here, we explore network connectivity as a potential neural correlate of ADHD diagnosis in early childhood.Method: We collected EEG data in 52 medication-naïve children with ADHD and in 77 typically developing controls (3-7 years). Data was collected with the EGI 128 HydroCel Sensor Net System, but to optimize the ICA, the data was down sampled to the 10-10 system. Connectivity was measured as the synchronization of the time series of each pair of electrodes. Subsequent analyses utilized graph theoretical methods to further characterize network connectivity.Results: Increased global efficiency, which measures the efficiency of information transfer across the entire brain, was associated with increased inattentive symptom severity. Further, this association was robust to controls for age, IQ, SES, and internalizing psychopathology.Conclusions: Overall, our findings indicate that increased global efficiency, which suggests a hyper-connected neural network, is associated with elevated ADHD symptom severity. These findings extend previous work reporting disruption of neural network connectivity in older children with ADHD into early childhood.

Longitudinal investigation of shyness and physiological vulnerability: Moderating influences of attention biases to threat and safety

Shyness has long been identified as a vulnerability factor to developing psychosocial problems, but there is heterogeneity in these observed outcomes. One potential factor underlying these relations is individual differences in threat sensitivity. Using a longitudinal design, we examined whether attentional biases toward social threat and safety measured during adulthood moderated the association between shyness measured in emerging adulthood (N = 83, n_female = 48; M_age = 23.56 years, SD_age = 1.09 years) and frontal electroencephalogram (EEG) asymmetry at rest, a physiological index of vulnerability to psychopathology, measured nearly a decade later in adulthood (M_age = 31.68 years, SD_age = 2.27 years). We found that only biases to threat moderated the association between shyness and resting frontal EEG asymmetry longitudinally. In individuals who displayed relative vigilance to social threat, shyness was associated with greater relative right frontal EEG activity at rest (i.e., increased physiological vulnerability). These findings suggest that attentional biases to threat may play a role in understanding the relation between shyness and some known physiological vulnerabilities to psychopathology in adults.

Using different methods for calculating frontal alpha asymmetry to study its development from infancy to 3 years of age in a large longitudinal sample

Frontal electroencephalography (EEG) alpha asymmetry (FAA), defined as the difference in frontal alpha power observed over the right and left frontal scalp regions, has been widely used in developmental research as a measure of multiple aspects of child behavior, such as temperament. Studies have used different equations to calculate FAA, which renders comparison of results across studies challenging. Furthermore, few studies have examined FAA's longitudinal stability across infancy and early childhood, which is a desirable feature of a temperament measure. We investigated the cross-sectional and the longitudinal correlations of FAA values from four different equations to calculate FAA used in the literature. We used baseline EEG data from a longitudinal sample of 321 infants and 168 3-year-old children (149 of whom had data at both timepoints). Consistent with previous work, FAA values calculated using two commonly used equations were highly correlated with each other cross-sectionally but not with values from a different equation that used log-transformed relative power. The log-transformed relative power FAA values were the only values that showed significant longitudinal stability. These findings suggest that researchers interested in FAA as a trait-like measure in children should consider using the relative power equation that renders stability across ages.

Computer-based inhibitory control training in children with Attention-Deficit/Hyperactivity Disorder (ADHD): Evidence for behavioral and neural impact

Attention-deficit hyperactivity disorder (ADHD) is the most commonly diagnosed psychological disorder of childhood. Medication and cognitive behavioral therapy are effective treatments for many children; however, adherence to medication and therapy regimens is low. Thus, identifying effective adjunct treatments is imperative. Previous studies exploring computerized training programs as supplementary treatments have targeted working memory or attention. However, many lines of research suggest inhibitory control (IC) plays a central role in ADHD pathophysiology, which makes IC a potential intervention target. In this randomized control trial (NCT03363568), we target IC using a modified stop-signal task (SST) training designed by NeuroScouting, LLC in 40 children with ADHD, aged 8 to 11 years. Children were randomly assigned to adaptive treatment (n = 20) or non-adaptive control (n = 20) with identical stimuli and task goals. Children trained at home for at least 5 days a week (about 15m/day) for 4-weeks. Relative to the control group, the treatment group showed decreased relative theta power in resting EEG and trending improvements in parent ratings of attention (i.e. decreases in inattentive behaviors). Both groups showed improved SST performance. There was not evidence for treatment effects on hyperactivity or teacher ratings of symptoms. Results suggest training IC alone has potential to positively impact symptoms of ADHD and provide evidence for neural underpinnings of this impact (change in theta power; change in N200 latency). This shows promising initial results for the use of computerized training of IC in children with ADHD as a potential adjunct treatment option for children with ADHD.

Exploring approach motivation: Correlating self-report, frontal asymmetry, and performance in the Effort Expenditure for Rewards Task

Frontal EEG asymmetry has been investigated as a physiological metric of approach motivation, with higher left frontal activity (LFA) suggested to reflect approach motivation. However, correlations between LFA and traditional metrics of approach motivation (e.g., scores from the behavioral inhibition system/behavioral approach system [BIS/BAS] survey) are inconsistent. It is also not clear how LFA correlates to approach motivation on an observable, behavioral level. Here, we tested correlations between BIS/BAS scores, LFA, and performance in the Effort Expenditure for Rewards Task (EEfRT). In our sample (n = 49), BIS/BAS results did not correlate to LFA values (resting or task states), and were also unrelated to EEfRT performance variables. We found evidence of significant and distinct correlations between LFA and EEfRT performance. Resting-state LFA positively correlated to effort expenditure on lower utility trials, where reward size and/or probability were suboptimal. Task-onset LFA captured in the first 5 min of the task was related to overall behavioral performance in the EEfRT. High task-onset LFA correlated to high trial completion rates, high-effort trial selection percentages, and overall monetary earnings. One interpretation of these initial findings is that resting-state LFA reflects approach tendencies to expend effort, but that this extends to suboptimal situations, whereas task-state LFA better reflects effortful approach toward high-utility goals. Given the relatively small sample size and the risk of Type I/II errors, we present the study as exploratory and the results as preliminary. However, the findings highlight interesting initial links between LFA and EEfRT performance. The need for larger replication studies is discussed.

Frontal EEG asymmetry moderates the associations between negative temperament and behavioral problems during childhood

Fearful inhibition and impulsivity-anger significantly predict internalizing and externalizing problems, respectively. An important moderator that may affect these associations is frontal EEG asymmetry (FA). We examined how temperament and FA at 6 years interactively predicted behavioral problems at 9 years. A community sample of 186 children (93 boys, 93 girls) participated in the study. Results indicated that the effect of fearful inhibition on parent-reported internalizing problems increased as children exhibited greater right FA. The effect of impulsivity-anger on parent-reported externalizing problems increased as children showed greater left FA. Because FA was allowed to vary rather than children being dichotomized into membership in left FA and right FA groups, we observed that children's FA contributed to the resilience process only when FA reached specific asymmetry levels. These findings highlight the importance of considering the different functions of FA in combination with specific dimensions of temperament in predicting children's socioemotional outcomes. Clinical implications include providing suggestions for intervention services by demonstrating the role of FA in developing behavioral problems and inspiring research on whether it is possible to alter EEG activation and thus potentially improve developmental outcomes.

Positive and Negative Emotionality at Age 3 Predicts Change in Frontal EEG Asymmetry across Early Childhood

Depression is characterized by low positive emotionality (PE) and high negative emotionality (NE), as well as asymmetries in resting electroencephalography (EEG) alpha power. Moreover, frontal asymmetry has itself been linked to PE, NE, and related constructs. However, little is known about associations of temperamental PE and NE with resting EEG asymmetries in young children and whether this association changes as a function of development. In a longitudinal study of 254 three-year old children, we assessed PE and NE at age 3 using a standard laboratory observation procedure. Frontal EEG asymmetries were assessed at age 3 and three years later at age 6. We observed a significant three-way interaction of preschool PE and NE and age at assessment for asymmetry at F3-F4 electrode sites, such that children with both low PE and high NE developed a pattern of increasingly lower relative left-frontal cortical activity over time. In addition, F7-F8 asymmetry was predicted by a PE by time interaction, such that the frontal asymmetry in children with high PE virtually disappeared by age 6. Overall, these findings suggest that early temperament is associated with developmental changes in frontal asymmetry, and that the combination of low PE and high NE predicts the development of the pattern of frontal symmetry that is associated with depression.

Maternal intrusiveness predicts infants' event-related potential responses to angry and happy prosody independent of infant frontal asymmetry

Infants' social-cognitive skills first develop within the parent-infant relationship, but large differences between parents exist in the way they approach and interact with their infant. These may have important consequences for infants' social-cognitive development. The current study investigated effects of maternal sensitive and intrusive behavior on 6- to 7-month-old infants' ERP responses to a socio-emotional cue that infants are often confronted with from an early age: emotional prosody in infant-directed speech. Infants may differ in their sensitivity to environmental (including parenting) influences on development, and the current study also explored whether infants' resting frontal asymmetry conveys differential susceptibility to effects of maternal sensitivity and intrusiveness. Results revealed that maternal intrusiveness was related to the difference in infants' ERP responses to happy and angry utterances. Specifically, P2 amplitudes in response to angry sounds were less positive than those in response to happy sounds for infants with less intrusive mothers. Whether this difference reflects an enhanced sensitivity to emotional prosody or a (processing) preference remains to be investigated. No evidence for differential susceptibility was found, as infant frontal asymmetry did not moderate effects of sensitivity or intrusiveness.

EEG power spectral slope differs by ADHD status and stimulant medication exposure in early childhood

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder characterized by hyperactivity/impulsivity and inattentiveness. Efforts toward the development of a biologically based diagnostic test have identified differences in the EEG power spectrum; most consistently reported is an increased ratio of theta to beta power during resting state in those with the disorder, compared with controls. Current approaches calculate theta/beta ratio using fixed frequency bands, but the observed differences may be confounded by other relevant features of the power spectrum, including shifts in peak oscillation frequency and altered slope or offset of the aperiodic 1/f-like component of the power spectrum. In the present study, we quantify the spectral slope and offset, peak alpha frequency, and band-limited and band-ratio oscillatory power in the resting-state EEG of 3- to 7-yr-old children with and without ADHD. We found that medication-naive children with ADHD had higher alpha power, greater offsets, and steeper slopes compared with typically developing children. Children with ADHD who were treated with stimulants had comparable slopes and offsets to the typically developing group despite a 24-h medication-washout period. We further show that spectral slope correlates with traditional measures of theta/beta ratio, suggesting the utility of slope as a neural marker over and above traditional approaches. Taken with past research demonstrating that spectral slope is associated with executive functioning and excitatory/inhibitory balance, these results suggest that altered slope of the power spectrum may reflect pathology in ADHD.NEW & NOTEWORTHY This article highlights the clinical utility of comprehensively quantifying features of the EEG power spectrum. Using this approach, we identify, for the first time, differences in the aperiodic components of the EEG power spectrum in children with attention-deficit/hyperactivity disorder (ADHD) and provide evidence that spectral slope is a robust indictor of an increase in low- relative to high-frequency power in ADHD.

Electroencephalographic spectral power as a marker of cortical function and disease severity in girls with Rett syndrome

Background

Rett syndrome is a neurodevelopmental disorder caused by a mutation in the X-linked MECP2 gene. Individuals with Rett syndrome typically develop normally until around 18 months of age before undergoing a developmental regression, and the disorder can lead to cognitive, motor, sensory, and autonomic dysfunction. Understanding the mechanism of developmental regression represents a unique challenge when viewed through a neuroscience lens. Are circuits that were previously established erased, and are new ones built to supplant old ones? One way to examine circuit-level changes is with the use of electroencephalography (EEG). Previous studies of the EEG in individuals with Rett syndrome have focused on morphological characteristics, but few have explored spectral power, including power as an index of brain function or disease severity. This study sought to determine if EEG power differs in girls with Rett syndrome and typically developing girls and among girls with Rett syndrome based on various clinical characteristics in order to better understand neural connectivity and cortical organization in individuals with this disorder.

Methods

Resting state EEG data were acquired from girls with Rett syndrome (n = 57) and typically developing children without Rett syndrome (n = 37). Clinical data were also collected for girls with Rett syndrome. EEG power across several brain regions in numerous frequency bands was then compared between girls with Rett syndrome and typically developing children and power in girls with Rett syndrome was compared based on these clinical measures. 1/ƒ slope was also compared between groups.

Results

Girls with Rett syndrome demonstrate significantly lower power in the middle frequency bands across multiple brain regions. Additionally, girls with Rett syndrome that are postregression demonstrate significantly higher power in the lower frequency delta and theta bands and a significantly more negative slope of the power spectrum. Increased power in these bands, as well as a more negative 1/ƒ slope, trended with lower cognitive assessment scores.

Conclusions

Increased power in lower frequency bands is consistent with previous studies demonstrating a “slowing” of the background EEG in Rett syndrome. This increase, particularly in the delta band, could represent abnormal cortical inhibition due to dysfunctional GABAergic signaling and could potentially be used as a marker of severity due to associations with more severe Rett syndrome phenotypes.

EEG asymmetry and BIS/BAS among healthy adolescents

Asymmetry in frontal alpha activation (FAA) has been associated with specific behavior patterns. Greater activation in the left frontal cortex is related to "approach" motivation, while greater activation in the right cortex is associated with "withdrawal" motivation. Moreover, resting FAA is stable over time among adults. This stability has not been demonstrated among adolescents, and the correspondence between resting FAA and personality has been inconsistently observed. The present study examined stability of FAA and the association between resting FAA and behavioral activation among adolescents. At baseline and 4 months, 99 adolescents completed a resting electroencephalogram (EEG) and a pencil-and-paper measure of personality (BIS/BAS). FAA showed good stability over time (Intra-class correlation coefficient=0.65, p<0.001), but there was no correlation between FAA and personality. Results are interpreted in light of a capability model of FAA; namely, that asymmetry may emerge under conditions of stimulation and recede during resting.

Developmental changes in electroencephalographic frontal asymmetry in young children at risk for depression

BACKGROUND

A number of studies have reported that depression is associated with lower relative left frontal activity in the alpha band (i.e. frontal asymmetry, or FA), as measured by electroencephalogram. FA has also been hypothesized to be a vulnerability marker for depression. If this is the case, FA should be evident in offspring of depressed mothers, a group at elevated risk for depression. However, the results of previous offspring studies have been inconsistent and none of these studies has considered whether the relationship between FA and risk changes over development in children.

METHOD

We assessed FA twice, at ages 3 and 6, in 253 never depressed children from a community sample. Maternal history of depressive disorders was determined by a diagnostic interview completed by the mothers at the first assessment.

RESULTS

There was a significant interaction between maternal depression and offspring age at assessment, indicating that FA exhibits different developmental trajectories depending on level of familial risk for depression. Offspring of depressed mothers exhibited a decreasing relative left FA over the course of early childhood, while offspring of nondepressed mothers exhibited relatively similar, symmetrical, levels of frontal alpha activity at both assessment points.

CONCLUSIONS

These results suggest that changes in FA from early to middle childhood distinguish those at risk for depression and that cross-sectional assessment of FA may have limited value in understanding risk. These results highlight the importance of considering development in understanding the role of FA in depression.

Frontal Electroencephalogram Asymmetry and Temperament Across Infancy and Early Childhood: An Exploration of Stability and Bidirectional Relations

The stability of frontal electroencephalogram (EEG) asymmetry, temperamental activity level and fear, as well as bidirectional relations between asymmetry and temperament across the first 4 years of life, were examined in a sample of 183 children. Children participated in annual laboratory visits through 48 months, providing EEG and maternal report of temperament. EEG asymmetry showed moderate stability between 10 and 24 months. Analyses revealed that more left asymmetry predicted later activity level across the first 3 years. Conversely, asymmetry did not predict fear. Rather, fear at 36 months predicted more right asymmetry at 48 months. Results highlight the need for additional longitudinal research of infants and children to increase understanding of bidirectional relations between EEG and temperament in typically developing populations.

Iron deficiency (ID) at both birth and 9 months predicts right frontal EEG asymmetry in infancy

This study considered effects of timing and duration of iron deficiency (ID) on frontal EEG asymmetry in infancy. In healthy term Chinese infants, EEG was recorded at 9 months in three experimental conditions: baseline, peek-a-boo, and stranger approach. Eighty infants provided data for all conditions. Prenatal ID was defined as low cord ferritin or high ZPP/H. Postnatal ID was defined as ≥ two abnormal iron measures at 9 months. Study groups were pre- and postnatal ID, prenatal ID only, postnatal ID only, and not ID. GLM repeated measure analysis showed a main effect for iron group. The pre- and postnatal ID group had negative asymmetry scores, reflecting right frontal EEG asymmetry (mean ± SE: -.18 ± .07) versus prenatal ID only (.00 ± .04), postnatal ID only (.03 ± .04), and not ID (.02 ± .04). Thus, ID at both birth and 9 months was associated with right frontal EEG asymmetry, a neural correlate of behavioral withdrawal and negative emotions.

Regional electroencephalogram (EEG) alpha power and asymmetry in older adults: a study of short-term test-retest reliability

Although regional alpha power and asymmetry measures have been widely used as indices of individual differences in emotional processing and affective style in younger populations, there have been relatively few studies that have examined these measures in older adults. Here, we examined the short-term test-retest reliability of resting regional alpha power (7.5-12.5 Hz) and asymmetry in a sample of 38 active, community-dwelling older adults (M age = 71.2, SD = 6.5 years). Resting electroencephalogram recordings were made before and after a perceptual computer task. Pearson and intra-class correlations indicated acceptable test-retest reliability for alpha power and asymmetry measures in all regions. Interestingly, alpha asymmetry appeared to be less affected by the task than was alpha power. Findings suggest that alpha asymmetry may reflect more enduring, "trait-like" characteristics, while alpha power may reflect more "state-like" processes in older adults.

Psychological Response to Sound Stimuli Evaluated by EEG

Abstract. Psychological responses to two kinds of sound stimuli (scary and soothing), as assessed by the Anterior Asymmetry and Emotion (AAE) and Comfort Vector (CV) models which are based on the prefrontal alpha wave, were investigated and the relation between their results is discussed. For the scary sound stimulus, subjects who showed greater withdrawal motivation (AAE) displayed a decreased pleasant state (CV), while subjects who showed higher approach motivation displayed opposite affective direction. There was a correlation between the AAE and CV models for the scary stimulus, but no correlation for the soothing stimulus. Both motivational and affective states could be evaluated by a combination of AAE and CV models. We suggest that joint consideration of these two models could lead to the multifaceted evaluation of a psychological state.

Variation in serotonin transporter linked polymorphic region (5-HTTLPR) short/long genotype modulates resting frontal electroencephalography asymmetries in children

Previous studies have documented the serotonin transporter linked polymorphic region (5-HTTLPR) as a genetic susceptibility variant that contributes to variability in outcomes related to affective psychopathology, with the short allele associated with negative affectivity and the long allele associated with positive affectivity. In a separate but related line of research, extensive evidence suggests that frontal electroencephalography (EEG) hemispheric asymmetry in the alpha band is also associated with risk for affective psychopathologies, with leftward asymmetry associated with approach-related behavior patterns and rightward frontal EEG asymmetry associated with withdrawn behavioral tendencies. We examined frontal EEG hemispheric asymmetries in relation to 5-HTTLPR genotyping in 70 children between 4 and 6 years of age. Analyses revealed that frontal EEG lateralization interacted with genotype such that children homozygous for the short allele exhibited rightward frontal EEG asymmetries, children who were homozygous for the long allele consistently exhibited a positive pattern of leftward asymmetry, and heterozygotes exhibited equivalent left and right frontal activity. These findings suggest that the 5-HTTLPR short allele may provide a degree of susceptibility for later affective psychopathology in adolescence and adulthood, through mediation of frontal brain activity that is associated with cognitive-behavioral withdrawal tendencies and negative affectivity.

Maternal sensitivity and infant response to frustration: the moderating role of EEG asymmetry

Two hundred and thirty-three 5-month-old infants and their mothers participated in a study designed to examine the influence of maternal sensitivity and infant neurophysiology, as well as interactions between these, on infants' regulatory behavior and reactivity to emotional challenge. Maternal sensitivity was measured during two mother-child free-play episodes prior to the challenge task. Infant neurophysiology was derived from a measure of resting EEG asymmetry collected during a baseline episode. Infant regulatory behaviors (mother orienting and distraction) and reactivity to challenge (negative affect) were assessed during an arm restraint procedure. Maternal sensitivity predicted mother-orienting behavior for all infants, regardless of baseline EEG asymmetry. Maternal sensitivity also predicted more distraction behaviors for infants with left frontal EEG asymmetry at baseline. In contrast, maternal sensitivity predicted more negative affect for infants with right frontal EEG asymmetry at baseline. These findings lend support for the hypothesis that maternal sensitivity and infant neurophysiological functioning interact to predict regulatory behavior and reactivity and are discussed in terms of the significance for understanding infant regulatory development in the first year of life.

Frontal EEG asymmetry moderates the effects of stressful life events on internalizing symptoms in children at familial risk for depression

This study examined whether frontal alpha electroencephalographic (EEG) asymmetry moderates the association between stressful life events and depressive symptoms in children at familial risk for depression. Participants included 135 children ages 6 to 13, whose mothers had either a history of depression or no history of major psychiatric conditions. Frontal EEG was recorded while participants watched emotion-eliciting films. Symptoms and stressful life events were obtained via the Child Behavior Check List and a clinical interview, respectively. High-risk children displayed greater relative right lateral frontal activation (F7/F8) than their low-risk peers during the films. For high-risk children, greater relative left lateral frontal activation moderated the association between stressful life events and internalizing symptoms. Specifically, greater relative left lateral frontal activation mitigated the effects of stress in at-risk children.

Anterior EEG asymmetry and the Modifier Model of Autism

Individual differences in the expression of autism complicate research on the nature and treatment of this disorder. In the Modifier Model of Autism (Mundy et al. 2007), we proposed that individual differences in autism may result not only from syndrome specific causal processes, but also from variability in generic, non-syndrome specific modifier processes that affect the social and emotional development of all people. One study supporting this model found that measures of resting anterior EEG asymmetry, a measure reflecting complex brain processes associated with generic individual differences in approach and avoidance motivation, may help explain differences in the expression of autism in children without intellectual disabilities (Sutton et al. 2005). In the current study, we partially replicated the observation that children with autism who exhibited a pattern of left frontal EEG asymmetry tended to display milder levels of social symptoms, although in the current sample this pattern applied only to HFA children with relatively lower verbal IQs. New observations indicated that left frontal EEG asymmetry was also associated with retrospective parent reports of significantly later age of onset of symptoms, but also higher levels of self-reported outward expressions of anger as well as symptoms of obsessive compulsive disorder in school-age higher functioning children with ASD. Therefore, the results of this study provide a new and fully independent set of observations, which indicate that individual differences in anterior EEG asymmetry may significantly moderate the expression and developmental course of autism. This observation may have clinical implications for identifying meaningful diagnostic sub-groups among children with autism.

Do positive and negative temperament traits interact in predicting risk for depression? A resting EEG study of 329 preschoolers

Researchers have long been interested in whether particular temperamental traits in childhood connote risk for depressive disorders. For example, children characterized as having high negative emotionality (NE; sadness, fear, anger) and low positive emotionality (PE; anhedonia, listlessness, and lack of enthusiasm) are hypothesized to be at risk for depression. Few studies, however, have examined whether (and how) these two temperamental dimensions interact to confer risk. In a sample of 329 preschoolers, the present study addressed this question by examining the relation between PE and NE and asymmetry in resting EEG activity in frontal and posterior regions, which are putative biomarkers for depression. Using a laboratory battery to define temperament, we found an interaction of PE and NE on posterior asymmetry. Specifically, when PE was high, NE was associated with greater relative right activity. When PE was low, NE was not related to posterior asymmetry. These results were driven by differences in EEG activity in right posterior regions, an area associated with emotional processing and arousal, and were specific to girls. We found no relation between temperament and frontal asymmetry. These findings suggest that, at least for girls, PE and NE may have an interactive effect on risk for depression.

Frontal brain electrical asymmetry and cardiac vagal tone predict biased attention to social threat

Individual differences in attention biases for motivationally significant stimuli have been reported in clinical and normative populations. Few studies, however, have attempted to examine potential biological mechanisms underlying differences in the cognitive processing of emotional stimuli. The present study examined the extent to which two well-validated psychophysiological vulnerability markers of affective style [i.e., frontal electroencephalogram (EEG) asymmetry and cardiac vagal tone] predicted biased attention toward rapid presentations (approximately 250 ms) of angry and happy facial expressions. We found that right frontal EEG asymmetry and low cardiac vagal tone, taken together, predicted approximately 37% of the variability in attentional vigilance for angry faces. Frontal EEG asymmetry and cardiac vagal tone did not predict attention for happy faces, independently of each other. Our results provide preliminary evidence that two well established psychophysiological indicators of affective style bias early processing of motivationally salient stimuli.

Frontal electroencephalogram asymmetry, salivary cortisol, and internalizing behavior problems in young adults who were born at extremely low birth weight

The authors examined internalizing behavior problems at middle childhood, adolescence, and young adulthood and brain-based measures of stress vulnerability in 154 right-handed, nonimpaired young adults (M age = 23 years): 71 (30 males, 41 females) born at extremely low birth weight (ELBW; < 1,000 g) and 83 (35 males, 48 females) controls born at normal birth weight (NBW). Internalizing behavior problems increased from adolescence to young adulthood among ELBW individuals. ELBW adults exhibited greater relative right frontal electroencephalogram activity at rest and more concurrent internalizing behavior problems than NBW controls. Being born at ELBW may have subtle influences on brain-behavior relations even in survivors without major impairments and evidence of these influences may not emerge until young adulthood.

Genetic and environmental influences on frontal EEG asymmetry and alpha power in 9-10-year-old twins

Modest genetic influences on frontal EEG asymmetry have been found in adults, but little is known about its genetic origins in children. Resting frontal asymmetry and alpha power were examined in 951 9-10-year-old twins. Results showed that in both males and females: (1) a modest but significant amount of variance in frontal asymmetry was accounted for by genetic factors (11-28%) with the remainder accounted for by non-shared environmental influences, and (2) alpha power were highly heritable, with 71-85% of the variance accounted for by genetic factors. Results suggest that the genetic architecture of frontal asymmetry and alpha power in late childhood are similar to that in adulthood and that the high non-shared environmental influences on frontal asymmetry may reflect environmentally influenced individual differences in the maturation of frontal cortex as well as state-dependent influences on specific measurements.