Parietal dysfunction during number processing in children with fetal alcohol spectrum disorders

Perinatal influences on academic achievement and the developing brain: a scoping systematic review

Introduction and methods

In this PRISMA-compliant systematic review, we identify and synthesize the findings of research in which neuroimaging and assessments of achievement have been used to examine the relationships among aspects of developmental programming, neurodevelopment, and achievement in reading and mathematics.

Results

Forty-seven studies met inclusion criteria. The majority examined the impact of prematurity (n = 32) and prenatal alcohol exposure (n = 13). Several prematurity studies reported a positive correlation between white-matter integrity of callosal fibers and executive functioning and/or achievement, and white matter properties were consistently associated with cognitive and academic performance in preterm and full-term children. Volumetric studies reported positive associations between academic and cognitive abilities and white and gray matter volume in regions such as the insula, putamen, and prefrontal lobes. Functional MRI studies demonstrated increased right-hemispheric language processing among preterm children. Altered activation of the frontoparietal network related to numerical abilities was also reported. Prenatal alcohol exposure studies reported alterations in white matter microstructure linked to deficits in cognitive functioning and academic achievement, including mathematics, reading, and vocabulary skills. Volumetric studies reported reductions in cerebral, cerebellar, and subcortical gray matter volumes associated with decreased scores on measures of executive functioning, attention, working memory, and academic performance. Functional MRI studies demonstrated broad, diffuse activation, reduced activation in canonical regions, and increased activation in non-canonical regions during numeric tasks.

Discussion

A preponderance of studies linked prematurity and prenatal alcohol exposure to altered neurodevelopmental processes and suboptimal academic achievement. Limitations and recommendations for future research are discussed.

Systematic review registration

Identifier: DOI 10.17605/OSF.IO/ZAN67.

Lower resting state functional connectivity partially mediates adverse effects of prenatal alcohol exposure on arithmetic performance in children

BACKGROUND

Fetal alcohol spectrum disorders (FASD) include a range of neurocognitive and behavioral impairments resulting from prenatal alcohol exposure (PAE). Among the PAE-related cognitive deficits, number processing is particularly affected. This study examines alterations in number processing networks and whether changes in functional connectivity mediate the adverse effects of PAE on arithmetic performance.

METHODS

Magnetic resonance imaging (MRI) was acquired in 57 children (mean (SD) age = 11.3 (+0.9) yr), 38 with FASD (19 fetal alcohol syndrome (FAS) or partial FAS (PFAS), 19 heavily exposed (HE)) and 19 controls. Whole-brain correlation analyses were performed from five seeds located in regions involved in number processing.

RESULTS

Children with FAS/PFAS showed dose-dependent reductions in resting state functional connectivity between the seed in the right (R) posterior superior parietal lobule and a cluster in the left (L) inferior frontal gyrus, and between a seed in the R horizontal intraparietal sulcus and clusters in the R precentral gyrus and L cerebellar lobule VI. HE children showed lower resting state functional connectivity in a subset of these regions. Lower functional connectivity in the two fronto-parietal connections partially mediated the adverse effects of PAE on arithmetic performance.

CONCLUSION

This study demonstrates PAE-related functional connectivity impairments in functional networks involved in number processing. The weaker connectivity between the R posterior superior parietal lobule and the L inferior frontal gyrus suggests that impaired verbal processing and visuospatial working memory may play a role in number processing deficits, while weaker connectivity between the R intraparietal sulcus and the R precentral gyrus points to poorer finger-based numerical representation, which has been linked to arithmetic computational skills.

RNA-seq analysis reveals prenatal alcohol exposure is associated with placental inflammatory cells and gene expression

BACKGROUND

Fetal alcohol spectrum disorders (FASD) are the most common preventable cause of birth defects and neurodevelopmental disorders worldwide. The placenta is the crucial interface between mother and fetus. Prenatal alcohol exposure (PAE) has been shown to alter placental structure and expression of genes in bulk placental tissue samples, but prior studies have not examined effects on placental cell-type composition or taken cell-type into consideration in transcriptome analyses.

METHODS

We leveraged an existent placenta single-cell RNA-seq dataset to perform cell-type deconvolution of bulk placental RNA-seq data from 35 heavy drinking pregnant women and 33 controls in a prospective birth cohort in Cape Town, South Africa. We used bivariate analyses and multivariable adjusted linear regression models to assess the relation of PAE on inferred placental cell-type proportions. We also examined differential expression of inflammatory response genes and PAE, using multivariable adjusted linear models.

RESULTS

Deconvolution analyses showed heterogeneous placenta cell-type composition in which stromal (27 %), endothelial (26 %) and cytotrophoblasts (18 %) were the predominant cell-types. PAE around conception was associated with a higher proportion of Hofbauer cells (B = 0.51, p = 0.035) in linear models adjusted for maternal age, infant sex, and gestational age. Among the 652 inflammatory genes examined, 35 were differential expressed in alcohol exposed placentas (FDR p < 0.05).

CONCLUSIONS

Our findings suggest that heavy alcohol exposure during pregnancy can influence the proportion of fetal placental villi macrophages (Hofbauer cells) and increased expression of inflammatory genes. Future studies are needed to further characterize these effects and to assess the potential functional roles of placental inflammation in FASD.

Stability and change in the interpretation of facial emotions in fetal alcohol spectrum disorders from childhood to adolescence

BACKGROUND

The ability to identify and interpret facial emotions plays a critical role in effective social functioning, which may be impaired in individuals with fetal alcohol spectrum disorders (FASD). We previously reported deficits in children with fetal alcohol syndrome (FAS) and partial FAS (PFAS) on the "Reading the Mind in the Eyes" (RME) test, which assesses the interpretation of facial emotion. This follow-up study in adolescents was designed to determine whether this impairment persists or represents a developmental delay; to classify the RME stimuli by valence (positive, negative, or neutral) and determine whether RME deficits differ by affective valence; and to explore how components of executive function mediate these associations.

METHODS

The RME stimuli were rated and grouped according to valence. Sixty-two participants who had been administered the RME in late childhood (mean ± SD = 11.0 ± 0.4 years) were re-administered this test during adolescence (17.2 ± 0.6 years). Overall and valence-specific RME accuracy was examined in relation to prenatal alcohol exposure (PAE) and FASD diagnosis.

RESULTS

Children with FAS (n = 8) and PFAS (n = 15) performed more poorly on the RME than non-syndromal heavily exposed (HE; n = 19) and control individuals (n = 20). By adolescence, the PFAS group performed similarly to HE and controls, whereas the FAS group continued to perform more poorly. No deficits were seen for positively valenced items in any of the groups. For negative and neutral items, in late childhood individuals with FAS and PFAS performed more poorly than HE and controls, but by adolescence only the FAS group continued to perform more poorly. Test-retest reliability was moderate across the two ages. At both timepoints, the effects in the FAS group were partially mediated by Verbal Fluency but not by other aspects of executive function.

CONCLUSIONS

Individuals with full FAS have greater difficulty interpreting facial emotions than those with non-syndromal HE and healthy controls in both childhood and adolescence. By contrast, RME deficits in individuals with PFAS in childhood represent developmental delay.

Magnitude comparison and automaticity in number processing in adolescents with prenatal alcohol exposure: An event-related potentials study

BACKGROUND

Individuals with fetal alcohol spectrum disorders may exhibit a distinct pattern of dysmorphic facial features, growth restriction, and cognitive deficits, particularly in arithmetic. Magnitude comparison, a fundamental element of numerical cognition, is modulated by the numerical distance effect, with numbers closer in value more difficult to compare than those further apart, and by the automaticity of the association of numerical values with their symbolic representations (Arabic numerals).

METHODS

We examined event-related potentials acquired during the Numerical Stroop numerical and physical tasks administered to 24 alcohol-exposed adolescents (eight fetal alcohol syndrome (FAS), eight partial FAS (PFAS), eight heavily exposed (HE) nonsyndromal) and 23 typically developing (TD), same- age controls. The distance effect was assessed on the numerical task to examine differences in reaction time (RT) and accuracy when two numbers are close in value (e.g., 1 vs. 2) compared to when the numbers are less close (e.g., 1 vs. 6). Automaticity was assessed in the physical task by examining the degree to which RT and accuracy are reduced when the relative physical size of two numerals is incongruent with their numerical values (e.g., 1 vs. 6).

RESULTS

Adolescents in all four groups performed behaviorally as expected on these relatively simple magnitude comparison tasks, but accuracy was poorer and RT was slower on both tasks in the FAS and PFAS than the HE and TD groups. At the neurophysiological level, in the numerical task, a higher level of prenatal alcohol exposure was associated with smaller P2p amplitude. In the physical task, only the TD and nonsyndromal HE groups exhibited the expected smaller P300 amplitude in the incongruent than the congruent condition.

CONCLUSIONS

These findings suggest that magnitude comparison in alcohol-exposed individuals may be mediated by recruitment of alternative neural pathways that are likely to be inefficient when number processing becomes more challenging.

Reading impairment in adolescents with fetal alcohol spectrum disorders

PURPOSE

To date, research on effects of prenatal alcohol exposure (PAE) has focused on a broad range of cognitive impairments, but relatively few studies have examined effects of PAE on development of reading skills. Although PAE has been linked to poorer reading comprehension, it remains unclear whether this impairment is attributable to deficits in phonological processing, word reading, oral language skills, and/or executive functioning.

METHODS

A comprehensive reading battery was administered to 10 adolescents with fetal alcohol syndrome (FAS); 16 with partial FAS; 30 nonsyndromal heavily-exposed; 49 controls.

RESULTS

PAE was related to poorer reading comprehension but not to single word reading or phonological processing, suggesting that the mechanics of reading are intact in adolescents with fetal alcohol spectrum disorders at this age. PAE-related impairment in reading comprehension was mediated, in part, by deficits in mastery of oral language skills, including vocabulary, language structure, and verbal fluency.

CONCLUSIONS

These results are consistent with research showing that reading comprehension in adolescence relies increasingly on linguistic comprehension abilities, especially once word reading becomes automatic and text complexity increases. Our findings suggest that reading-impaired adolescents with PAE will benefit from intervention programs targeting vocabulary knowledge, language structure, verbal fluency, and reading comprehension skills.

Effects of Prenatal Alcohol Exposure on the Volumes of the Lateral and Medial Walls of the Intraparietal Sulcus

Fetal alcohol spectrum disorders (FASD) continue to be the leading preventable cause of intellectual disability in the U.S., Europe, and in endemic areas, such as the Western Cape region of South Africa. Arithmetic is highly sensitive to prenatal alcohol exposure (PAE). The intraparietal sulcus (IPS) is known to play a critical role in number processing. In this study, we investigate whether smaller IPS volumes play a role in the number-processing deficits observed in children with PAE. Participants were 52 9- to 14-year-old children from a historically disadvantaged community in Cape Town, who are participating in our ongoing studies on the effects of PAE on the brain. The IPS was manually parcellated into its medial (MIPS) and lateral (LIPS) walls on magnetic resonance images. The study aimed to examine: (1) the effects of PAE on IPS regional volumes and asymmetry, (2) whether IPS regional volumes are related to number processing performance and, if so, whether these relations are moderated by PAE and (3) potential mediation by regional IPS volumes of the relation between PAE and number processing performance. Total intracranial volume (TIV) was associated with volumes in all regions except the right LIPS. Both left MIPS and left LIPS volumes were significantly smaller in children in the fetal alcohol syndrome (FAS)/partial FAS (PFAS) group compared to controls. The finding in the left LIPS remained significant after controlling for potential confounders and after adjustment for the smaller overall brain size of the children in the FAS/PFAS group. Smaller left LIPS volumes in the FAS/PFAS group may account for the absence of left-right asymmetry in the LIPS in children with FAS/PFAS compared to controls and nonsyndromal heavily exposed (HE) children. Bilaterally, larger MIPS volumes were associated with better WISC IQ Arithmetic scores. These effects, however, were not moderated by the degree of PAE, and regional IPS volumes did not mediate the effect of PAE on WISC Arithmetic scores. Although we found that certain regions of the IPS were smaller in children with FAS and PFAS, these PAE-induced changes in IPS volume did not mediate the alcohol-related deficits in arithmetic.

Infant circulating MicroRNAs as biomarkers of effect in fetal alcohol spectrum disorders

Prenatal alcohol exposure (PAE) can result in cognitive and behavioral disabilities and growth deficits. Because alcohol-related neurobehavioral deficits may occur in the absence of overt dysmorphic features or growth deficits, there is a need to identify biomarkers of PAE that can predict neurobehavioral impairment. In this study, we assessed infant plasma extracellular, circulating miRNAs (exmiRNAs) obtained from a heavily exposed Cape Town cohort to determine whether these can be used to predict PAE-related growth restriction and cognitive impairment. PAE, controlling for smoking as a covariate, altered 27% of expressed exmiRNAs with clinically-relevant effect sizes (Cohen's d ≥ 0.4). Moreover, at 2 weeks, PAE increased correlated expression of exmiRNAs across chromosomes, suggesting potential co-regulation. In confirmatory factor analysis, the variance in expression for PAE-altered exmiRNAs at 2 weeks and 6.5 months was best described by three-factor models. Pathway analysis found that factors at 2 weeks were associated with (F1) cell maturation, cell cycle inhibition, and somatic growth, (F2) cell survival, apoptosis, cardiac development, and metabolism, and (F3) cell proliferation, skeletal development, hematopoiesis, and inflammation, and at 6.5 months with (F1) neurodevelopment, neural crest/mesoderm-derivative development and growth, (F2) immune system and inflammation, and (F3) somatic growth and cardiovascular development. Factors F3 at 2 weeks and F2 at 6.5 months partially mediated PAE-induced growth deficits, and factor F3 at 2 weeks partially mediated effects of PAE on infant recognition memory at 6.5 months. These findings indicate that infant exmiRNAs can help identify infants who will exhibit PAE-related deficits in growth and cognition.

Fetal Alcohol Exposure Alters BOLD Activation Patterns in Brain Regions Mediating the Interpretation of Facial Affect

BACKGROUND

Although deficits in the interpretation of affective facial expressions have been described clinically and in behavioral studies of fetal alcohol spectrum disorders (FASD), effects of prenatal alcohol exposure on the neural networks that mediate affective appraisal have not previously been examined.

METHODS

We administered a nonverbal event-related fMRI affective appraisal paradigm to 64 children (mean age = 12.5 years; 18 with fetal alcohol syndrome (FAS) or partial FAS (PFAS), 18 nonsyndromal heavily exposed (HE), and 28 controls). Happy, sad, angry, fearful, and neutral faces and pixelated control images were presented sequentially in a randomized order. The child indicated whether the currently displayed face showed the same or different affect as the previous one.

RESULTS

Data from whole-brain analyses showed that all groups activated the appropriate face processing neural networks. Region of interest analyses indicated that, compared to HE and control children, the FAS/PFAS group exhibited greater blood oxygenation level-dependent (BOLD) signal changes when processing neutral faces than pixelated images in 2 regions that form part of the visual sensory social brain network, which plays an important role in the initial processing of facial affect. By contrast, BOLD signal when processing angry faces was weaker for the FAS/PFAS group in a region involved in the processing of facial identity and facial expressions and in a region involved in the recognition and selection of behavioral responses to aggressive behavior.

CONCLUSIONS

These findings of greater BOLD signal in the FAS/PFAS group in response to neutral faces suggest less efficient neural processing of more difficult to interpret emotions, and the weaker BOLD response to angry faces suggests altered processing of angry stimuli. Although behavioral performance did not differ in this relatively simple affective appraisal task, these data suggest that in children with FAS and PFAS, the appraisal of neutral affect and anger is likely to be more effortful in more challenging and dynamic social contexts.

An fMRI investigation of neural activation predicting memory formation in children with fetal alcohol spectrum disorders

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Expected brain regions activated during memory formation in FASD and Control children.

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Prenatal alcohol predicted differences in brain activations during memory formation.

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More extensive neural activation during successful memory formation in FAS/PFAS group.

Prenatal alcohol exposure (PAE) is associated with physical anomalies, growth restriction, and a range of neurobehavioral deficits. Although declarative memory impairment has been documented extensively in individuals with fetal alcohol spectrum disorders (FASD), this cognitive process has been examined in only one functional magnetic resonance imaging (fMRI) study, and mechanisms underlying this impairment are not well understood. We used an event-related fMRI design to examine neural activations during visual scene encoding that predict subsequent scene memory in 51 right-handed children (age range = 10–14 years, M = 11.3, SD = 1.3) whose mothers had been recruited and interviewed prospectively about their alcohol use during pregnancy. Following examination by expert dysmorphologists, children were assigned to one of three FASD diagnostic groups: FAS/PFAS (n_FAS = 7; n_PFAS = 4), nonsyndromal heavily exposed (HE; n = 14), and Controls (n = 26). Subsequent memory was assessed in a post-scan recognition test, and subsequent memory activations were examined by contrasting activations during encoding of scenes that were subsequently remembered (hits) to those for incorrectly judged as ‘new’ (misses). Recognition accuracy did not differ between groups. Pooled across groups, we observed extensive bilateral subsequent memory effects in regions including the hippocampal formation, posterior parietal cortex, and occipital cortex—a pattern consistent with previous similar studies of typically developing children. Critically, in the group of children with FAS or PFAS, we observed activations in several additional regions compared to HE and Control groups. Given the absence of between-group differences in recognition accuracy, these data suggest that in achieving similar memory compared to children in the HE and Control groups, children with FAS and PFAS recruit more extensive neural resources to achieve successful memory formation.

Reduced Hippocampal Volumes Partially Mediate Effects of Prenatal Alcohol Exposure on Spatial Navigation on a Virtual Water Maze Task in Children

BACKGROUND

Prenatal alcohol exposure (PAE) has been linked to poorer performance on the Morris water maze (MWM), a test of spatial navigation in rodents that is dependent on hippocampal functioning. We recently confirmed these findings in children with PAE on a human analog of the MWM, the virtual water maze (VWM). Previous studies have shown that the hippocampus is particularly sensitive to PAE. Our aim was to determine whether hippocampal volume mediates the relation between PAE and virtual navigation.

METHODS

VWM and MRI hippocampal data were collected from 50 right-handed 10-year-old children in a heavily exposed Cape Town, South African sample. PAE data had been collected from their mothers during pregnancy, and the children were examined by expert fetal alcohol spectrum disorder (FASD) dysmorphologists. In the VWM, the participant attempts to learn the location of a hidden platform in a virtual pool of water across a series of learning trials using only distal room cues. Hippocampal volumes were derived using FreeSurfer from MRI scans administered within 1 week of completing the VWM task.

RESULTS

Both the fetal alcohol syndrome (FAS)/partial FAS and nonsyndromal heavy-exposed (HE) groups had smaller hippocampal volumes than controls. PAE was associated with reduced right hippocampal volumes even after control for total intracranial volume (ICV). Hippocampal volume was also positively associated with VWM performance. The relation between PAE and VWM performance was partially mediated by right hippocampal volume but not by total ICV.

CONCLUSIONS

These data confirm previous reports linking PAE to poorer spatial navigation on the VWM and are the first to provide direct evidence that volume reductions in this region partially mediate the relation of FASD diagnosis to place learning, suggesting that PAE specifically impairs the ability to encode the spatial information necessary for successful location of the hidden platform on a navigation task.

Prenatal Alcohol Exposure Alters Error Detection During Simple Arithmetic Processing: An Electroencephalography Study

BACKGROUND

Arithmetic is the domain of academic achievement most consistently related to prenatal alcohol exposure (PAE). Error detection, an important aspect of arithmetic processing, can be examined in a mathematical verification task. Electroencephalographic (EEG) studies using such tasks have shown bursts of synchronized theta-band activity in response to errors. We assessed this activity for error detection in adolescents with PAE and typically developing (TD) matched controls. We predicted that the PAE group would show smaller theta bursts during error detection and weaker responses depending on the size of the error discrepancy.

METHODS

Participants' mothers were recruited during pregnancy and interviewed about their alcohol consumption using a timeline follow-back interview. Participants were followed from infancy and diagnosed for fetal alcohol syndrome (FAS) or partial FAS (PFAS) by expert dysmorphologists. EEGs were recorded for 48 adolescents during a verification task, which required differentiation between correct/incorrect solutions to simple equations; incorrect solutions had small or large deviations from correct solutions.

RESULTS

Performance was good-excellent. The PAE group showed lower accuracy than the TD group: Accuracy was inversely related to diagnosis severity. The TD and heavily exposed (HE) nonsyndromal groups showed the expected differentiation in theta-burst activity between correct/incorrect equations, but the FAS/PFAS groups did not. Degree of impairment in brain response to errors reflected severity of diagnosis: The HE group showed the same differentiation between correct/incorrect solutions as TD but failed to differentiate between levels of discrepancy; PFAS showed theta reactions only in response to large error discrepancies; and FAS did not respond to small or large discrepancies.

CONCLUSIONS

Arithmetical error-related theta activity is altered by PAE and can be used to distinguish between exposed and nonexposed individuals and within diagnostic groups, supporting the use of numerical and quantitative processing patterns to derive a neurocognitive profile that could facilitate diagnosis and treatment of fetal alcohol spectrum disorders.

Effects of Fetal Substance Exposure on Offspring Substance Use

Prenatal exposure to alcohol and drugs is associated with physical, cognitive, and behavioral problems across the offspring's lifespan and an increased risk of alcohol and drug use in adolescent and young adult offspring. These prenatal effects continue to be evident after control for demographic background and parental alcohol and drug use. Behavior problems in childhood and adolescence associated with prenatal exposures may serve as a mediator of the prenatal exposure effects on offspring substance use.

Deficits in arithmetic error detection in infants with prenatal alcohol exposure: An ERP study

Prenatal alcohol exposure (PAE) is associated with a range of physical, cognitive, and behavioral problems, particularly in arithmetic. We report ERP data collected from 32 infants (mean age = 6.8 mo; SD = 0.6; range = 6.1–8.1; 16 typically developing [TD]; 16 prenatally alcohol-exposed) during a task designed to assess error detection. Evidence of error monitoring at this early age suggests that precursors of the onset of executive control can already be detected in infancy. As predicted, the ERPs of the TD infants, time-locked to the presentation of the solution to simple arithmetic equations, showed greater negative activity for the incorrect solution condition at middle-frontal scalp areas. Spectral analysis indicated specificity to the 6–7 Hz frequency range. By contrast, the alcohol-exposed infants did not show the increased middle-frontal negativity seen in the TD group nor the increased power in the 6–7 Hz frequency, suggesting a marked developmental delay in error detection and/or early impairment in information processing of small quantities. Overall, our research demonstrates that (a) the brain network involved in error detection can be identified and highly specified in TD young infants, and (b) this effect is replicable and can be utilized for studying developmental psychopathology at very early ages.

Spatial Navigation in Children and Young Adults with Fetal Alcohol Spectrum Disorders

BACKGROUND

Rodent studies have consistently shown that prenatal alcohol exposure (PAE) impairs performance on the Morris water maze (MWM), a test of spatial navigation. A previous study comparing boys with fetal alcohol syndrome (FAS) to controls found poorer performance on the virtual water maze (VWM), a human analogue of the MWM. We examined PAE effects on virtual navigation in both sexes using the VWM in a moderately exposed Detroit cohort (N = 104; mean = 19.4 year) and a heavily exposed Cape Town, South African cohort (N = 62; mean = 10.4 year).

METHODS

The task requires the participant to learn the location of a hidden platform in a virtual pool of water. The set of acquisition trials requires the participant to learn the location of the hidden platform and to return to that location repeatedly. The single-probe trial requires the participant to return to that location without knowing that the platform has been removed.

RESULTS

No effects of FASD diagnostic group or PAE were detected on virtual navigation in the Detroit moderately exposed cohort. By contrast, in the more heavily exposed Cape Town cohort, the FAS/partial FAS (PFAS) group took longer to locate the hidden platform during acquisition than nonsyndromal heavily exposed (HE) and control groups, an effect that persisted even after controlling for IQ. Among boys, both the FAS/PFAS and HE groups performed more poorly than controls during acquisition, and both boys and girls born to women who binge drank performed more poorly than those born to abstainers/light drinkers. Both amount and frequency of PAE were related to poorer performance during the probe trial at 10 years of age.

CONCLUSIONS

These data demonstrate deficits in spatial navigation among heavily exposed syndromal boys and girls and in nonsyndromal exposed boys.

Clinical presentation, diagnosis, and management of fetal alcohol spectrum disorder

Although prenatal alcohol exposure causes craniofacial anomalies, growth retardation, neurological abnormalities, cognitive impairment, and birth defects, fetal alcohol spectrum disorder is underdiagnosed. Global prevalence of fetal alcohol spectrum disorder is 0·77%, with a higher prevalence of 2-5% in Europe and North America, highlighting the need for increased diagnosis and treatment. However, diagnosis remains challenging because of the poor reliability of self-reported maternal drinking histories, an absence of sensitive biomarkers, and the infrequency of diagnostic dysmorphic facial features among individuals with fetal alcohol spectrum disorder. Different diagnostic systems and disagreements over criteria have slowed progress in the diagnosis and management of the disorder. Neuroimaging shows abnormalities in brain structure, cortical development, white matter microstructure, and functional connectivity in individuals with fetal alcohol spectrum disorder. These abnormalities modify developmental trajectories and are associated with deficits in cognition, executive function, memory, vision, hearing, motor skills, behaviour, and social adaptation. Promising trials of nutritional interventions and cognitive rehabilitation therapies are underway, with the aim of treating cognitive deficits in fetal alcohol spectrum disorders.

Changes to the somatosensory barrel cortex in C57BL/6J mice at early adulthood (56 days post-natal) following prenatal alcohol exposure

Children with Fetal Alcohol Spectrum Disorder (FASD) have impaired sensory processing skills as a result of neurodevelopmental anomalies. The somatosensory barrel field of rodent brain is a readily accessible model for studying the effects of alcohol exposure. Within the barrel field, the posterior medial barrel subfield (PMBSF) receives sensory inputs from the large vibrissae on the contralateral face. This study reports on the consequence of prenatal exposure to alcohol on the somatosensory cortices of mice later in life. Two control groups, a sucrose and a non-treated control, were also examined. At postnatal day (PND) 56 the cerebral hemisphere of mice from each group were processed for cytochrome oxidase reactivity. In contrast to previous studies, there were no significant differences in the mean areas of: (I) the PMBSF enclosure, (II) the PMBSF barrels, (III) the individual PMBSF barrels and (IV) the septal portion of the PMBSF in the alcohol group compared to the controls. However barrel sizes in rows D and E in the alcohol group were significantly reduced, indicating an alcohol-induced damage on the barrel development and which may reduce the amount of the cortex devoted to processing somatosensory input- a common defect seen in children with FASD.

Development and validation of a quantitative choline food frequency questionnaire for use with drinking and non-drinking pregnant women in Cape Town, South Africa

Background

Although animal and human studies have demonstrated interactions between dietary choline and fetal alcohol spectrum disorders, dietary choline deficiency in pregnancy is common in the US and worldwide. We sought to develop and validate a quantitative food frequency questionnaire (QFFQ) to estimate usual daily choline intake in pregnant mothers.

Methods

A panel of nutrition experts developed a Choline-QFFQ food item list, including sources with high choline content and the most commonly consumed choline-containing foods in the target population. A data base for choline content of each item was compiled. For reliability and validity testing in a prospective longitudinal cohort, 123 heavy drinking Cape Coloured pregnant women and 83 abstaining/light-drinking controls were recruited at their first antenatal clinic visit. At 3 prenatal study visits, each gravida was interviewed about alcohol, smoking, and drug use, and administered a 24-hour recall interview and the Choline-QFFQ.

Results

Across all visits and assessments, > 78% of heavy drinkers and controls reported choline intake below the Dietary Reference Intakes adequate intake level (450 mg/day). Women reported a decrease in choline intake over time on the QFFQ. Reliability of the QFFQ across visits was good-to-acceptable for 2 of 4 group-level tests and 4 of 5 individual-level tests for both drinkers and controls. When compared with 24-hr recall data, validity of the QFFQ was good-to-acceptable for 3 of 4 individual-level tests and 3 of 5 group-level tests. For controls, validity was good-to-acceptable for all 4 individual-level tests and all 5 group-level tests.

Conclusions

To our knowledge, this is the first quantitative choline food frequency screening questionnaire to be developed and validated for use with both heavy and non-drinking pregnant women and the first to be used in the Cape Coloured community in South Africa. Given the high prevalence of inadequate choline intake and the growing evidence that maternal choline supplementation can mitigate some of the adverse effects of prenatal alcohol exposure, this tool may be useful for both research and future clinical outreach programs.

Prenatal alcohol exposure affects brain function during place learning in a virtual environment differently in boys and girls

INTRODUCTION

Although performance deficits in place learning have been reported in fetal alcohol spectrum disorders (FASD), neural correlates of these deficits have not been investigated. This functional magnetic resonance imaging (fMRI) study of 57 children (41 alcohol-exposed; 16 controls; mean age = 9.4 years; 29 boys) examined effects of prenatal alcohol exposure (PAE) on place learning in a virtual environment, the computer-generated (CG) arena.

METHODS

Functional magnetic resonance imaging data were acquired while children passively viewed a recording of an experimenter completing the task. Visible-target blocks involved navigation to a visible platform. During invisible-target blocks, the platform appeared only when the experimenter moved over it. After the scan, all children performed a post-test during which they had to navigate to the location of the invisible platform.

RESULTS

Although there were no group differences in post-test performance for sex or FASD diagnosis, PAE in boys was associated with poorer performance and reduced activation in the parahippocampal gyrus (PHG), precuneus, posterior cingulate, frontal and temporal lobes, caudate, insula, claustrum, lentiform nucleus, and thalamus. By contrast, PAE was not associated with performance or activation in any regions in girls.

DISCUSSION AND CONCLUSION

Girls and boys are known to use different navigation strategies. Boys rely more on an allocentric navigational strategy and girls more on landmarks. Poorer recruitment of the PHG, a region known to mediate allocentric navigation, in more heavily exposed boys may explain the observed dose-dependent place learning deficit. The absence of PAE effects in girls suggests that landmark-based navigational strategies may be less affected by alcohol exposure.

Prenatal Ethanol Exposure and Neocortical Development: A Transgenerational Model of FASD

Fetal Alcohol Spectrum Disorders, or FASD, represent a range of adverse developmental conditions caused by prenatal ethanol exposure (PrEE) from maternal consumption of alcohol. PrEE induces neurobiological damage in the developing brain leading to cognitive-perceptual and behavioral deficits in the offspring. Alcohol-mediated alterations to epigenetic function may underlie PrEE-related brain dysfunction, with these changes potentially carried across generations to unexposed offspring. To determine the transgenerational impact of PrEE on neocortical development, we generated a mouse model of FASD and identified numerous stable phenotypes transmitted via the male germline to the unexposed third generation. These include alterations in ectopic intraneocortical connectivity, upregulation of neocortical Rzrβ and Id2 expression accompanied by both promoter hypomethylation of these genes and decreased global DNA methylation levels. DNMT expression was also suppressed in newborn PrEE cortex, providing further insight into how ethanol perturbs DNA methylation leading to altered regulation of gene transcription. These PrEE-induced, transgenerational phenotypes may be responsible for cognitive, sensorimotor, and behavioral deficits seen in humans with FASD. Thus, understanding the possible epigenetic mechanisms by which these phenotypes are generated may reveal novel targets for therapeutic intervention of FASD and lead to advances in human health.

Alcohol-Related Alterations in Placental Imprinted Gene Expression in Humans Mediate Effects of Prenatal Alcohol Exposure on Postnatal Growth

BACKGROUND

A growing body of evidence in animal models has implicated alcohol-induced alterations in epigenetic programming as an important mechanism in fetal alcohol spectrum disorders (FASD). Imprinted genes, a subset of epigenetically regulated genes that are sensitive to the prenatal environment, are chiefly involved in growth and neurobehavior. We tested the hypothesis that alterations in placental imprinted gene expression mediate fetal alcohol growth restriction.

METHODS

Placental expression of 109 genes previously shown to be imprinted and expressed in the placenta was assessed using the NanoString™ nCounter Analysis System in flash-frozen samples from 34 heavy drinkers and 31 control women in Cape Town, South Africa, from whom prospective pregnancy alcohol consumption data had been obtained. Length/height, weight, and head circumference were measured at 6.5 and 12 months and at an FASD diagnostic clinic (at ages 1.1 to 4.6 years) that we organized. Imprinted gene expression between exposed and control placentas was compared using the limma R package. The relation of alcohol exposure to World Health Organization length-for-age z-scores was examined before and after inclusion of expression for each alcohol-related imprinted gene, using hierarchical mixed regression models with repeated measures.

RESULTS

Heavy drinkers averaged 8 standard drinks on 2 to 3 days/wk (vs. 0 for controls). Prenatal alcohol exposure was associated with smaller length/height and weight during the postnatal period. Heavy exposure was related to alterations in expression of 11 of 93 expressed imprinted genes, including increased expression of 5 genes found to be negatively associated with growth and decreased expression of 3 genes positively associated with growth. Alcohol-related alterations in expression of 5 genes statistically mediated the effect of prenatal alcohol exposure on length.

CONCLUSIONS

These findings identify alcohol-related alterations in placental imprinted gene expression as potential biomarkers of adverse effect in FASD and suggest that these alterations may play a mechanistic role in fetal alcohol growth restriction. Future studies are needed to determine whether alterations in imprinted gene expression also mediate FASD neurobehavioral deficits and whether such alterations are amenable to intervention.

Sensorimotor network alterations in children and youth with prenatal alcohol exposure

Children with prenatal alcohol exposure (PAE) often have impaired sensorimotor function. While altered brain structure has been noted in sensorimotor areas, the functional brain alterations remain unclear. This study aims to investigate sensorimotor brain networks in children and youth with PAE using resting-state functional magnetic resonance imaging (rs-fMRI). A parcellation-based network analysis was performed to identify brain networks related to hand/lower limb and face/upper limb function in 59 children and youth with PAE and 50 typically developing controls. Participants with PAE and controls had similar organization of the hand and face areas within the primary sensorimotor cortex, but participants with PAE had altered functional connectivity (FC) between the sensorimotor regions and the rest of the brain. The sensorimotor regions in the PAE group showed less connectivity to certain hubs of the default mode network and more connectivity to areas of the salience network. Overall, our results show that despite similar patterns of organization in the sensorimotor network, subjects with PAE have increased FC between this network and other brain areas, perhaps suggesting overcompensation. These alterations in the sensorimotor network lay the foundation for future studies to evaluate interventions and treatments to improve motor function in children with PAE.

Altered Parietal Activation during Non-symbolic Number Comparison in Children with Prenatal Alcohol Exposure

Number processing is a cognitive domain particularly sensitive to prenatal alcohol exposure, which relies on intact parietal functioning. Alcohol-related alterations in brain activation have been found in the parietal lobe during symbolic number processing. However, the effects of prenatal alcohol exposure on the neural correlates of non-symbolic number comparison and the numerical distance effect have not been investigated. Using functional magnetic resonance imaging (fMRI), we examined differences in brain activation associated with prenatal alcohol exposure in five parietal regions involved in number processing during a non-symbolic number comparison task with varying degrees of difficulty. fMRI results are presented for 27 Cape Colored children (6 fetal alcohol syndome (FAS)/partial FAS, 5 heavily exposed (HE) non-sydromal, 16 controls; mean age ± SD = 11.7 ± 1.1 years). Fetal alcohol exposure was assessed by interviewing mothers using a timeline follow-back approach. Separate subject analyses were performed in each of five regions of interest, bilateral horizontal intraparietal sulci (IPS), bilateral posterior superior parietal lobules (PSPL), and left angular gyrus (left AG), using the general linear model with predictors for number comparison and difficulty level. Mean percent signal change for each predictor was extracted for each subject for each region to examine group differences and associations with continuous measures of alcohol exposure. Although groups did not differ in performance, controls activated the right PSPL more during non-symbolic number comparison than exposed children, but this was not significant after controlling for maternal smoking, and the right IPS more than children with fetal alcohol syndrome (FAS) or partial FAS. More heavily exposed children recruited the left AG to a greater extent as task difficulty increased, possibly to compensate, in part, for impairments in function in the PSPL and IPS. Notably, in non-syndromal heavily exposed children activation was impaired in the right PSPL, but spared in the right IPS. These results extend previous findings of poor right IPS recruitment during symbolic number processing in FAS/PFAS, indicating that mental representation of relative quantity is affected by prenatal alcohol exposure for both symbolic and non-symbolic representations of quantity.

Children with Heavy Prenatal Alcohol Exposure Exhibit Atypical Gait Characteristics

BACKGROUND

Impaired motor function in children with histories of prenatal exposure to alcohol has been previously reported but, to date, no studies using quantitatively based analyses have been performed to assess gait in these children.

METHODS

Gait of children with (n = 18) or without (n = 26) prenatal alcohol exposure was assessed using an electronically instrumented walkway. Children completed blocks of trials traversing the walkway with different combinations of walking condition (increased, self-paced, and decreased cadence) and direction (forward and backward). Gait velocity, cadence, stride length, step width, foot angle, and double support time, as well as the variability of these temporal-spatial markers, were used to assess gait.

RESULTS

Results indicated that, in comparison with typically developing children, alcohol-exposed children produced exaggerated foot angle and increased step width. Additionally, alcohol-exposed children produced greater intrasubject variability of gait velocity and walking cadence while walking forward and backward, and greater variability in step width when walking backward and for all 3 walking conditions.

CONCLUSIONS

The results indicate that selected gait markers are adversely affected by prenatal exposure to alcohol. Clinicians and front-line personnel (e.g., teachers) should provide movement enriched experiences to help ameliorate these alcohol-related deficits.

Radiological studies of fetal alcohol spectrum disorders in humans and animal models: An updated comprehensive review

Fetal Alcohol Spectrum Disorders encompass a wide range of birth defects in children born to mothers who consumed alcohol during pregnancy. Typical mental impairments in FASD include difficulties in life adaptation and learning and memory, deficits in attention, visuospatial skills, language and speech disabilities, mood disorders and motor disabilities. Multimodal imaging methods have enabled in vivo studies of the teratogenic effects of alcohol on the central nervous system, giving more insight into the FASD phenotype. This paper offers an up-to-date comprehensive review of radiological findings in the central nervous system in studies of prenatal alcohol exposure in both humans and translational animal models, including Magnetic Resonance Imaging, Computed Tomography, Positron Emission Tomography, Single Photon Emission Tomography and Ultrasonography.

Heavy Prenatal Alcohol Exposure is Related to Smaller Corpus Callosum in Newborn MRI Scans

BACKGROUND

Magnetic resonance imaging (MRI) studies have consistently demonstrated disproportionately smaller corpus callosa in individuals with a history of prenatal alcohol exposure (PAE) but have not previously examined the feasibility of detecting this effect in infants. Tissue segmentation of the newborn brain is challenging because analysis techniques developed for the adult brain are not directly transferable, and segmentation for cerebral morphometry is difficult in neonates, due to the latter's incomplete myelination. This study is the first to use volumetric structural MRI to investigate PAE effects in newborns using manual tracing and to examine the cross-sectional area of the corpus callosum (CC).

METHODS

Forty-three nonsedated infants born to 32 Cape Coloured heavy drinkers and 11 controls recruited prospectively during pregnancy were scanned using a custom-designed birdcage coil for infants, which increases signal-to-noise ratio almost 2-fold compared to the standard head coil. Alcohol use was ascertained prospectively during pregnancy, and fetal alcohol spectrum disorders diagnosis was conducted by expert dysmorphologists. Data were acquired using a multi-echo FLASH protocol adapted for newborns, and a knowledge-based procedure was used to hand-segment the neonatal brains.

RESULTS

CC was disproportionately smaller in alcohol-exposed neonates than controls after controlling for intracranial volume. By contrast, CC area was unrelated to infant sex, gestational age, age at scan, or maternal smoking, marijuana, or methamphetamine use during pregnancy.

CONCLUSIONS

Given that midline craniofacial anomalies have been recognized as a hallmark of fetal alcohol syndrome in humans and animal models since this syndrome was first identified, the CC deficit identified here in newborns may support early identification of a range of midline structural impairments. Smaller CC during the newborn period may provide an early indicator of fetal alcohol-related cognitive deficits that have been linked to this critically important brain structure in childhood and adolescence.

Academic Difficulties in Children with Prenatal Alcohol Exposure: Presence, Profile, and Neural Correlates

BACKGROUND

Academic achievement was evaluated in children with heavy prenatal alcohol exposure to determine potential strengths and weaknesses, evaluate the utility of different definitions for identifying low academic performance, and explore the neural correlates that may underlie academic performance.

METHODS

Children (8 to 16 years) were assessed using the WIAT-II. Patterns of performance were examined in 2 subject groups: children with heavy prenatal alcohol exposure (n = 67) and controls (n = 61). A repeated-measures MANCOVA examining group differences on academic domain (reading, spelling, math) scores was conducted. Post hoc comparisons examined within-group profiles. Numbers and percentage of children with low achievement were calculated using several criteria. In a subsample (n = 42), neural correlates were analyzed using FreeSurfer v5.3 to examine relations between cortical structure (thickness and surface area) and performance.

RESULTS

The alcohol-exposed group performed worse than controls on all domains and had a unique academic profile, supported by a significant group × academic domain interaction (p < 0.001). For the alcohol-exposed group, math reasoning was significantly lower than numerical operations, which was significantly lower than spelling and word reading. Over half of the alcohol-exposed group (58.2%) demonstrated low achievement on 1 or more academic domains. The number and percentage of children meeting criteria for low achievement varied based on the domain and definition used. The imaging analysis identified several surface area clusters that were differentially related to math (L superior parietal and R lateral/middle occipital) and spelling (bilateral inferior and medial temporal) performance by group, with no relations for the other academic domains. Generally, scores improved as surface area decreased in controls, whereas no relation or a positive relation was observed in the alcohol-exposed group.

CONCLUSIONS

Alcohol-exposed children demonstrated deficits in academic performance across domains and definitions, with a relative weakness in math functioning. Atypical brain development may contribute to these impairments in academic achievement. Understanding academic difficulties can assist in advocating effectively for alcohol-exposed children.

Functional hyperconnectivity vanishes in children with developmental dyscalculia after numerical intervention

Developmental dyscalculia (DD) is a developmental learning disability associated with deficits in processing numerical and mathematical information. Although behavioural training can reduce these deficits, it is unclear which neuronal resources show a functional reorganization due to training. We examined typically developing (TD) children (N = 16, mean age: 9.5 years) and age-, gender-, and handedness-matched children with DD (N = 15, mean age: 9.5 years) during the performance of a numerical order task with fMRI and functional connectivity before and after 5-weeks of number line training. Using the intraparietal sulcus (IPS) as seed region, DD showed hyperconnectivity in parietal, frontal, visual, and temporal regions before the training controlling for age and IQ. Hyperconnectivity disappeared after training, whereas math abilities improved. Multivariate classification analysis of task-related fMRI data corroborated the connectivity results as the same group of TD could be discriminated from DD before but not after number line training (86.4 vs. 38.9%, respectively). Our results indicate that abnormally high functional connectivity in DD can be normalized on the neuronal level by intensive number line training. As functional connectivity in DD was indistinguishable to TD’s connectivity after training, we conclude that training lead to a re-organization of inter-regional task engagement.

Differential Recruitment of Brain Regions During Response Inhibition in Children Prenatally Exposed to Alcohol

BACKGROUND

Response inhibition is a distinct aspect of executive function that is frequently impaired in children with fetal alcohol spectrum disorders (FASD). We used a Go/NoGo (GNG) task in a functional MRI protocol to investigate differential activation of brain regions in the response inhibition network in children diagnosed with full or partial fetal alcohol syndrome (FAS/PFAS), compared with healthy controls.

METHODS

A rapid, event-related task with 120 Go and 60 NoGo trials was used to study children aged 8 to 12 years-8 with FAS/PFAS, 17 controls. Letters were projected sequentially, with Go and NoGo trials randomly interspersed across the task. BOLD signal in the whole brain was contrasted for the correct NoGo minus correct Go trials between the FAS/PFAS and control groups.

RESULTS

Compared to the FAS/PFAS group, controls showed greater activation of the inferior frontal and anterior cingulate network linked to response inhibition in typically developing children. By contrast, the FAS/PFAS group showed greater BOLD response in dorsolateral prefrontal cortex and other middle prefrontal regions, suggesting compensation for inefficient function of pathways that normally mediate inhibitory processing. All group differences were significant after control for potential confounding variables. None of the effects of prenatal alcohol exposure on activation of the regions associated with response inhibition were attributable to the effects of this exposure on IQ.

CONCLUSIONS

This is the first FASD GNG study in which all participants in the exposed group met criteria for a diagnosis of full FAS or PFAS. Although FASD is frequently comorbid with attention deficit hyperactivity disorder, the pattern of brain activation seen in these disorders differs, suggesting that different neural pathways mediate response inhibition in FASD and that different interventions for FASD are, therefore, warranted.