Utilizing maternal prenatal cognition as a predictor of newborn brain measures of intellectual development

Identifying reliable indicators of cognitive functioning prior to age five has been challenging. Prior studies have shown that maternal cognition, as indexed by intellectual quotient (IQ) and years of education, predict child intelligence at school age. We examined whether maternal full scale IQ, education, and inhibitory control (index of executive function) are associated with newborn brain measures and toddler language outcomes to assess potential indicators of early cognition. We hypothesized that maternal indices of cognition would be associated with brain areas implicated in intelligence in school-age children and adults in the newborn period. Thirty-seven pregnant women and their newborns underwent an MRI scan. T2-weighted images and surface-based morphometric analysis were used to compute local brain volumes in newborn infants. Maternal cognition indices were associated with local brain volumes for infants in the anterior and posterior cingulate, occipital lobe, and pre/postcentral gyrus - regions associated with IQ, executive function, or sensori-motor functions in children and adults. Maternal education and executive function, but not maternal intelligence, were associated with toddler language scores at 12 and 24 months. Newborn brain volumes did not predict language scores. Overall, the pre/postcentral gyrus and occipital lobe may be unique indicators of early intellectual development in the newborn period. Given that maternal executive function as measured by inhibitory control has robust associations with the newborn brain and is objective, brief, and easy to administer, it may be a useful predictor of early developmental and cognitive capacity for young children.

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

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

Association of postnatal exposure to mixture of bisphenol A, Di-n-butyl phthalate and Di-(2-ethylhexyl) phthalate with Children's IQ at 5 Years of age: Mothers and Children's environmental health (MOCEH) study

Early childhood is important for neurodevelopment, and exposure to endocrine disruptors such as bisphenol A (BPA) and phthalates in this period may cause neurodevelopmental disorders and delays. The present study examined the association between exposure to mixtures of BPA and three metabolites of phthalates in early childhood and IQ at 5 years of age. The Mother and Children's Environmental Health (MOCEH) study is a prospective birth cohort study conducted in Korea with 1751 pregnant women enrolled from 2006 to 2010. After excluding those without relevant data, 47 children were included in the final analysis. We measured children's urinary concentrations of metabolites of endocrine-disrupting chemicals (Bisphenol A, mono-(2-ethyl-5-oxohexyl) phthalate, mono-(2-ethyl-5-hydroxyhexyl) phthalate and mono-(2-ethyl-5-butyl) phthalate) at ages of 24 and 36 months. We evaluated the children's IQ with the Korean Wechsler Intelligence Test at the age of 5 years. After adjusting for potential confounders, a multiple linear regression was conducted to examine the associations between individual endocrine-disrupting chemicals and the IQ of the children. Weighted Quantile Sum (WQS) regression and quantile-based g-computation were used to assess the association between IQ at age 5 and exposure to mixtures of BPA and phthalates. In the single-chemical analyses, mono-(2-ethyl-5-butyl) phthalate exposure at 36 months was adversely associated with children's IQ (β = -4.93, 95% confidence interval (CI): -9.22, -0.64). In the WQS regression and quantile-based g-computation analyses, exposure to the mixture of BPA and phthalates was associated with lower IQ [β = -9.13 (P-value = 0.05) and β = -9.18 (P-value = 0.05), respectively]. The largest contributor to the overall association was exposure to mono-(2-ethyl-5-butyl) phthalate at 36 months. In the present study, postnatal exposure to mixtures of BPA and three metabolites of phthalates was associated with decreased IQ of children at age 5.

Associations between early infections and childhood cognition in the Newcastle Thousand Families Study birth cohort

Childhood infections have been shown to stunt growth, contribute to malnutrition and reduce cognition in early adulthood. This study aimed to assess relationships between early life infections and childhood cognition at age 11 years in the Newcastle Thousand Families Study (NTFS). The analysis included 741 members from the NTFS who had complete data for infections between birth and 5 years, and the 11-plus examinations. School records from the 11-plus examinations showed cognitive (IQ), English (EQ) and arithmetic (AQ) abilities. Housing conditions, overcrowding, birth order and social class were recorded at birth. Helicobacter pylori seropositivity was measured at age 49-51 years. Multivariable linear regression was used to examine relationships between infections and cognition. The total number of infections in the first 5 years of life was not significantly associated with IQ, EQ or AQ, nor were there significant relationships between cognitive outcomes and most infections. Tonsillitis did display a positive, significant association with IQ after adjustment for confounders (b = 6.43, 95% CI 0.92, 11.94, p = 0.022). Lower respiratory tract infections (LRTIs) showed significant negative relationships with all cognitive outcomes. H. pylori seropositivity at age 50 exhibited negative, significant relationships with EQ (p = 0.014) and AQ (p = 0.024) after adjustment for confounders. Although no significant relationship between overall infections and cognition were found, there were indications that LRTIs and gastrointestinal system infections may limit cognitive development. Given these infections remain prevalent, further research regarding severity and recurrence of infections and how they affect childhood cognition is needed.

Home Improvement: Evaluating Secular Changes in NLSY HOME-Cognitive Stimulation and Emotional Support Scores

This study evaluated changes over time in the quality of children's home environment, using the Home Observation Measurement of the Environment (HOME). Longitudinal increases in HOME scores were predicted by both theory and past empirical results. Analysis of the National Longitudinal Survey of Youth Children data (N = 5715, aged 0-14) suggested that HOME scores have been increasing, and that the increase is a family-level phenomenon. The data were a sample of children born to mothers who were approximately representative of the United States in 1979. An increase in HOME scores occurred primarily for the three age categories younger than ten. Effect sizes were of approximately the same magnitude as the Flynn effect for intelligence. These results have implications for policy and future research regarding the home environment.

The effect of confounding variables in studies of lead exposure and IQ

Methods proposed to address confounding variables frequently do not adequately distinguish confounding from covariation. A confounder is a variable that correlates both with the outcome and the major exposure variable. Accurate treatment of confounding is crucial to low dose extrapolation of the effects of chemical exposures based on epidemiology studies. This study explores the limitations of current regression models in extrapolation to the low dose region of the dose-response curve due to the existence of unrecognized and uncontrolled confounding, using epidemiological data for lead. Based on the reported data in analyses by Lanphear and colleagues and Crump and colleagues, and drawing on other studies, Wilson and Wilson considered maternal IQ, HOME score, SES, parental education, birthweight, smoking, and race as characteristic variables which may have interaction effects. This analysis identifies confounding variables based on the seven longitudinal cohorts in analyses conducted by Lanphear and colleagues and by Crump and colleagues and confirms maternal IQ, HOME score, maternal education and maternal marital status at birth are "Highly Likely" confounders, while race is a "Likely" confounder. The cohort data were reanalyzed using the methods presented by Crump and colleagues while also considering the interaction among the identified confounding variables. This analysis determined that confounders influence IQ estimates in a quantifiable way that may exceed or at least obscure previously-reported effects of blood lead on IQ with blood lead levels below 5 µg/dL; however, limitations in the datasets make predictions of the low dose dose-response analysis questionable.

The link between maternal and child verbal abilities: An indirect effect through maternal responsiveness

Language abilities in early childhood show stability over time and play an important role in the development of other cognitive processes. Identifying modifiable environmental risk factors is important to informing prevention and early intervention efforts. Maternal verbal ability has been previously linked to child verbal ability. The current study examined whether maternal and child verbal abilities were linked indirectly through early childhood maternal responsiveness. Data come from a longitudinal birth cohort study. Participants included 133 mothers and their children recruited from maternity wards shortly after birth. Maternal verbal ability was measured using the Vocabulary subtest from the Wechsler Abbreviated Scale of Intelligence, Second Edition (child age 8 months). Child verbal ability was assessed using the Peabody Picture Vocabulary Test (36 months). A latent maternal responsiveness variable was estimated using three developmentally sensitive indicators; one during infancy (child age 8 months) and two when children were 36 months. Results of a structural equation model indicated a significant indirect effect from maternal verbal abilities to child verbal abilities through maternal responsiveness. This indirect path was significant even after inclusion of another indirect path from maternal executive functioning to child verbal ability through maternal responsiveness (which was not significant). Future studies will benefit from experimental, genetically sensitive and/or cross-lagged designs to allow for conclusions related to directionality and causality. This body of research has implications for the study of the intergenerational transmission of verbal abilities and associated skills, behaviours and adaptive outcomes.

Early cognitive skills of Mexican-origin children: The roles of parental nativity and legal status

Although one-third of children of immigrants have undocumented parents, little is known about their early development. Using data from the Los Angeles Family and Neighborhood Survey and decennial census, we assessed how children's cognitive skills at ages 3 to 5 vary by ethnicity, maternal nativity, and maternal legal status. Specifically, Mexican children of undocumented mothers were contrasted with Mexican children of documented mothers and Mexican, white, and black children with U.S.-born mothers. Mexican children of undocumented mothers had lower emergent reading skills than all other groups and lower emergent mathematics skills than all groups with U.S.-born mothers. Multilevel regression models showed that differences in reading skills are explained by aspects of the home environment, but the neighborhood context also matters. Cross-level interactions suggest that immigrant concentration boosts emergent reading and mathematics skills for children with undocumented parents, but does not similarly benefit children whose parents are native born.

The Impact of Low-risk Prematurity on Maternal Behaviour and Toddler Outcomes

This short-term longitudinal research project was designed to compare the maternal behaviour of mothers whose toddlers had been born preterm with the maternal behaviour of mothers whose toddlers had been born at term; the outcomes for the toddlers were also assessed. Twenty-one toddlers who had been born preterm with low medical risk (1460-2420 grams) were compared with 21 term toddlers who were matched in terms of social class. The heightened maternal responsiveness that had been observed during the first year with preterm infants had disappeared by 12 months, and by 20 months it was the mothers whose infants had been born at term who were more vocally responsive. During the second year, the mothers of preterm toddlers were characterised by more maternal control behaviour than were the mothers of term toddlers. Assessments of cognitive and language performance at the gestationally corrected ages of 12 and 20 months did not differentiate the toddlers who had been born preterm and term. In terms of play skills, reflected during interaction with their mothers at 12 and 20 months, the preterm toddlers were more actively involved than were the term toddlers. Despite the successful adjustment of these low-risk preterm toddlers, maternal behaviour was affected by the circumstances of preterm birth, even after 20 months.

The Social Behaviour of 11- to 12-year-old Children Born as Low Birthweight and/or Premature Infants

Two studies (Study 1 and Study 2) were carried out to compare the social behaviour of school-aged children born as premature and/or low birthweight infants, with that of children born as healthy fullterm infants. Participants in Study 1 were 147 11-year-olds of whom 49 (29 females and 20 males) were reported by their parents to have been born prematurely. Participants in Study 2 were 84 11-year-old boys, 28 of whom were born with a birthweight less than 2000 grams. These at-risk subjects were followed for a period of two years. Subgroups within both study groups were matched with control groups using gender, age, and the school environment as common factors. Children in the target classes of Study 1 were classified using the Revised Class Play (Masten, Morison, & Pelligrini, 1985) and the Peer Nomination Inventory (Perry, Kusel, & Perry, 1988). In Study 2, the children completed the Pupil Evaluation Inventory (PEI) (Pekarik, Prinz, Liebert, Weintraub, & Neale, 1976). Findings suggest that aggressive behaviour is not related to birth status and that birth status is not linked to prosocial behaviour associated with sociability and likeability. However, both studies showed that children (boys and girls alike) born as premature or low birthweight infants, expressed greater levels of internalised social behaviour. These findings suggest that infants born premature and/or with a low birthweight may be less socially competent with their peers during their school-age years.

Mothers' and Fathers' Sensitivity and Children's Cognitive Development in Low-Income, Rural Families

This study examines associations between maternal and paternal sensitive parenting and child cognitive development across the first 3 years of life using longitudinal data from 630 families with co-residing biological mothers and fathers. Sensitive parenting was measured by observational coding of parent-child interactions and child cognitive development was assessed with the Bayley Scales of Infant Development and the Wechsler Preschool and Primary Scales of Intelligence. There were multiple direct and indirect associations between parenting and cognitive development across mothers and fathers, suggesting primary effects, carry-forward effects, spillover effects across parents, and transactional effects across parents and children. Associations between parenting and cognitive development were statistically consistent across mothers and fathers, and the cumulative effects of early parenting on later cognitive development were comparable to the effects of later parenting on later cognitive development. As interpreted through a family systems framework, findings suggest additive and interdependent effects across parents and children.

Predictors of intelligence at the age of 5: family, pregnancy and birth characteristics, postnatal influences, and postnatal growth

Parental education and maternal intelligence are well-known predictors of child IQ. However, the literature regarding other factors that may contribute to individual differences in IQ is inconclusive. The aim of this study was to examine the contribution of a number of variables whose predictive status remain unclarified, in a sample of basically healthy children with a low rate of pre- and postnatal complications. 1,782 5-year-old children sampled from the Danish National Birth Cohort (2003–2007) were assessed with a short form of the Wechsler Preschool and Primary Scale of Intelligence – Revised. Information on parental characteristics, pregnancy and birth factors, postnatal influences, and postnatal growth was collected during pregnancy and at follow-up. A model including study design variables and child’s sex explained 7% of the variance in IQ, while parental education and maternal IQ increased the explained variance to 24%. Other predictors were parity, maternal BMI, birth weight, breastfeeding, and the child’s head circumference and height at follow-up. These variables, however, only increased the explained variance to 29%. The results suggest that parental education and maternal IQ are major predictors of IQ and should be included routinely in studies of cognitive development. Obstetrical and postnatal factors also predict IQ, but their contribution may be of comparatively limited magnitude.

The effect of alcohol binge drinking in early pregnancy on general intelligence in children

OBJECTIVE

To examine the effects of binge alcohol consumption during early pregnancy, including the number of binge episodes and the timing of binge drinking, on general intelligence in 5-year-old children.

DESIGN

Follow-up study.

SETTING

Neuropsychological testing in four Danish cities 2003-2008.

POPULATION

A cohort of 1617 women and their children sampled from the Danish National Birth Cohort.

METHODS

Participants were sampled on the basis of maternal alcohol consumption during pregnancy. At 5 years of age the children were tested with six subtests from the Wechsler Preschool and Primary Scale of Intelligence - Revised (WPPSI-R). Parental education, maternal IQ, prenatal maternal smoking, the child's age at testing, the gender of the child, and tester were considered core confounding factors, whereas the full model also controlled for prenatal maternal average alcohol intake, maternal age, maternal pre-pregnancy body mass index (BMI), parity, home environment, postnatal parental smoking, health status, and indicators for hearing and vision impairment.

MAIN OUTCOME MEASURE

WPPSI-R.

RESULTS

There were no systematic or significant differences in general intelligence between children of mothers reporting binge drinking and children of mothers with no binge episodes, except that binge drinking in gestational weeks 1-2 significantly reduced the risk of low, full-scale IQ (OR 0.54; 95% CI 0.31-0.96) when adjusted for core confounding factors. The results were otherwise not statistically significantly related to the number of binge episodes (with a maximum of 12) and timing of binge drinking.

CONCLUSIONS

We found no systematic association between binge drinking during early pregnancy and child intelligence. However, binge drinking reduced the risk of low, full-scale IQ in gestational weeks 1-2. This finding may be explained by residual confounding.

The effect of different alcohol drinking patterns in early to mid pregnancy on the child's intelligence, attention, and executive function

OBJECTIVE

To conduct a combined analysis of the estimated effects of maternal average weekly alcohol consumption, and any binge drinking, in early to mid pregnancy on general intelligence, attention, and executive function in 5-year-old children.

DESIGN

Follow-up study.

SETTING

Neuropsychological testing in four Danish cities 2003-2008.

POPULATION

A cohort of 1628 women and their children sampled from the Danish National Birth Cohort.

METHODS

Participants were sampled based on maternal alcohol consumption during early pregnancy. At age 5 years, the children were tested for general intelligence, attention, and executive function. The three outcomes were analysed together in a multivariate model to obtain joint estimates and P values for the association of alcohol across outcomes. The effects of low to moderate alcohol consumption and binge drinking in early pregnancy were adjusted for a wide range of potential confounding factors.

MAIN OUTCOME MEASURES

Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R), the Test of Everyday Attention for Children at Five (TEACh-5), and the Behavior Rating Inventory of Executive Functions (BRIEF) scores.

RESULTS

Multivariate analyses showed no statistically significant effects arising from average weekly alcohol consumption or any binge drinking, either individually or in combination. These results replicate findings from separate analyses of each outcome variable.

CONCLUSIONS

The present study contributes comprehensive methodological and statistical approaches that should be incorporated in future studies of low to moderate alcohol consumption and binge drinking during pregnancy. Furthermore, as no safe level of drinking during pregnancy has been established, the most conservative advice for women is not to drink alcohol during pregnancy. However, the present study suggests that small volumes consumed occasionally may not present serious concern.

Late-preterm birth and its association with cognitive and socioemotional outcomes at 6 years of age

INTRODUCTION

Late-preterm birth (34-36 weeks' gestation) has been associated with a risk for long-term cognitive and socioemotional problems. However, many studies have not incorporated measures of important contributors to these outcomes, and it is unclear whether effects attributed to gestational age are separate from fetal growth or its proxy, birth weight for gestational age.

METHOD

Data came from a study of low- and normal-weight births sampled from urban and suburban settings between 1983 and 1985 (low birth weight, n = 473; normal birth weight; n = 350). Random sampling was used to pair singletons born late-preterm with a term counterpart whose birth weight z score was within 0.1 SD of his or her match (n = 168 pairs). With random-effects models, we evaluated whether pairs differed in their IQ scores and teacher-reported behavioral problems at the age of 6 years.

RESULTS

In adjusted models, late-preterm birth was associated with an increased risk of full-scale (adjusted odds ratio [aOR]: 2.35 [95% confidence interval (CI): 1.20-4.61]) and performance (aOR: 2.04 [95% CI: 1.09-3.82]) IQ scores below 85. Late-preterm birth was associated with higher levels of internalizing and attention problems, findings that were replicated in models that used thresholds marking borderline or clinically significant problems (aOR: 2.35 [95% CI: 1.28-4.32] and 1.76 [95% CI: 1.04-3.0], respectively).

CONCLUSIONS

Late-preterm birth is associated with behavioral problems and lower IQ at the age of 6, independent of maternal IQ, residential setting, and sociodemographics. Future research is needed to investigate whether these findings result from a reduction in gestational length, in utero (eg, obstetric complications) or ex-utero (eg, neonatal complications) factors marked by late-preterm birth, or some combination of these factors.

Effects of perinatal HIV infection and early institutional rearing on physical and cognitive development of children in Ukraine

To study the effects of perinatal HIV-1 infection and early institutional rearing on the physical and cognitive development of children, 64 Ukrainian uninfected and HIV-infected institutionalized and family-reared children were examined (mean age = 50.9 months). Both HIV infection and institutional care were related to delays in physical and cognitive development, with a larger effect of the rearing environment. Family care, even of compromised quality, was found to be more favorable for children's physical and cognitive development than institutional care. The impact of the quality of child care on physical and cognitive development is discussed in light of future interventions.

Paediatric HIV and neurodevelopment in sub-Saharan Africa: a systematic review

OBJECTIVE

To determine the degree of motor, cognitive, language and social-emotional impairment related to HIV infection in children living in sub-Saharan Africa (SSA).

METHODS

Literature searches using MEDLINE and PsycINFO. Additionally, the reference lists of previous reviews were checked to ensure that all eligible studies were identified. Cohen's d, a measure of effect size, was computed to estimate the level of impairment.

RESULTS

Six reports met the inclusion criteria. In infancy a consistent delay in motor development was observed with a median value of Cohen's d = 0.97 at 18 months, indicating a severe degree of impairment. Mental development showed a moderate delay at 18 months, with a median value d = 0.67. Language delay did not appear until 24 months of age, d = 0.91. Less clear findings occurred in older subjects.

CONCLUSION

Although HIV has been shown to affect all domains of child functioning, motor development is the most apparent in terms of severity, early onset, and persistence across age groups. However, motor development has been the most widely assessed domain while language development has been less vigorously evaluated in SSA, hence an accurate quantitative estimate of the effect cannot yet be made.

The Home Observation for Measurement of the Environment Revisited

This review describes the Home Observation for Measurement of the Environment (HOME). After describing the structure of the instrument, it shows how it has been used successfully in studies on normally developing children and on samples drawn from high-risk populations. These are followed by studies showing how the HOME has been used to evaluate interventions. Although most interventions are not designed primarily on the basis of the HOME outcomes, the instrument has been used as a measure of the effectiveness of the intervention schedule. HOME has been used extensively in research to reveal relationships between several aspects of the home environment and children's developmental outcomes. The very good relationship between HOME scores and children's measures of developmental competence has also been found in non-normative populations and research has attempted to identify the specific aspects of the home environment, as indexed by the HOME subscales that reveal the strengths or the weaknesses of homes of at-risk populations.

Sleep-wake patterns in preterm infants and 6 month's home environment: implications for early cognitive development

AIMS

This study examined the relationship between early organization of sleep-wake states and developmental outcome at 6-month-old premature infants.

STUDY DESIGN

This was a prospective randomized study that evaluated the sleep-wake states of healthy premature infants in the nursery environment for two successive 72-h periods, at 32 and 36 weeks gestational age.

SUBJECTS

Thirty-four healthy premature infants.

OUTCOME MEASURES

Three sleep-wake parameters: percent of quiet sleep, activity level and total amount of sleep, were studied with miniature activity monitors attached to the infant's ankles. The rearing environments of the infants were also assessed at 6 months of age, using the HOME Inventory. Finally, child developmental status was recorded by means of the Mental Development Index (MDI) of the Bayley Scales for Infant Development, at a chronological age of 6 months.

RESULTS

Lower total time spent in night sleep, higher mean level of night activity level, and a later rich home environment were all predictive of higher Bayley scores (MDI) at a chronological age of 6 months. Regression analysis indicated that early biological maturity was more strongly related to the child's developmental status than later home environment, although both contributed to the prediction.

CONCLUSIONS

These results suggest that biological factors may be significant predictors early in development, whereas the impact of environmental influences increases with development.

Aspectos cognitivos e comportamentais na média meninice de crianças nascidas pré-termo e com muito baixo peso

O objetivo deste estudo consiste em avaliar o desenvolvimento cognitivo e o comportamento de 20 crianças de 8 a 10 anos nascidas pré-termo e baixo peso (<= 1500g) no HCFMRP. Na avaliação cognitiva utilizou-se o RAVEN, o WISC e a avaliação assistida e na avaliação do comportamento utilizou-se a Escala de Rutter. Verificou-se que as crianças apresentaram desempenho intelectual na média, tendendo ao rebaixamento cognitivo. Na avaliação cognitiva assistida, a maior parte das crianças foi classificada como "ganhadora" e foram capazes, com a ajuda da examinadora, de implementar e manter estratégias eficientes para a resolução do problema. Quanto ao comportamento, foram detectados índices sugestivos de necessidade de atendimento psicológico para a maioria das crianças. Verificaram-se correlações significativas entre os resultados das avaliações cognitivas entre si e entre estas e a do comportamento. Os resultados apontam para a necessidade de seguimento psicológico longitudinal desse grupo de risco para problemas de desenvolvimento.