Cognitive functions mediate the effect of preterm birth on mathematics skills in young children

Relationships between cortisol levels across early childhood and processing speed at age 4.5 years in children born very preterm

Children born very low gestational age (VLGA, 29-32 weeks gestational age [GA]) display slower processing speed and altered hypothalamic pituitary adrenal (HPA) axis function, with greater effects in those born extremely low gestational age (ELGA; 24-28 weeks GA). We investigated trajectories of HPA axis activity as indexed by cortisol output and patterns across cognitive assessment at ages 1.5, 3 and 4.5 years, comparing children born ELGA and VLGA and associations with 4.5-year processing speed. In a prospective longitudinal cohort study, infants born very preterm (<33 weeks gestation) returned for developmental assessment at ages 1.5, 3, and 4.5 years. At each age, children completed standardized cognitive testing and saliva samples collected before (Pretest), during (During) and after (End) challenging cognitive tasks were assayed for cortisol. For the total group (n = 188), cortisol area under the curve with respect to ground (AUCg) decreased, while cortisol reactivity to challenge (Pre-test to During) increased from 1.5 to 3 years, remaining stable to 4.5 years. This longitudinal pattern was related to higher Processing Speed (WPPSI-IV) scores at 4.5 years. Children born ELGA displayed higher AUCg than VLGA, particularly at age 3, driven by higher Pre-test cortisol levels. Overall, relative to those born VLGA, children born ELGA displayed greater cortisol responsivity to cognitive challenge. A higher setpoint of cortisol levels at age 3-years in children born ELGA may reflect altered HPA axis regulation more broadly and may contribute to difficulties with information processing in this population, critical for academic and social success.

Mathematics abilities associated with adaptive functioning in preschool children born preterm

It is well known that infants born very preterm (VPT) often demonstrate deficits in mathematical abilities in early childhood which are associated with poorer academic outcomes. Mathematic skills are also critical for other areas of functioning. However, it is not known whether mathematics skills are associated with adaptive functioning in children born preterm. Infants born at ≤31 weeks gestation and full term were recruited at birth and followed over time. At the 36-month corrected age assessment, children were administered the Early Number Concepts subtest of the Differential Abilities Scale, Second Edition, and caregivers completed the Adaptive Behavior Assessment System, Third Edition. After controlling for age, sex, cognitive abilities, and caregiver education, performance on the mathematics measure was uniquely and positively associated with adaptive behavior for preschool children in the VPT group only. Exploratory analyses revealed this association to be specifically related to the Practical and Social composites. Knowledge of concepts of number and quantity were associated with better adaptive functioning, particularly for behaviors related to functioning at home and in the community and play/social functioning, for children born VPT. Although replication is warranted, it would appear that mathematical skills may be an important early intervention target for children born VPT.

Sex differences in the effects of prematurity and/or low birthweight on neurodevelopmental outcomes: systematic review and meta-analyses

BACKGROUND

Premature birth and/or low birthweight have long-lasting effects on cognition. The purpose of the present systematic review is to examine whether the effects of prematurity and/or low birth weight on neurodevelopmental outcomes differ between males and females.

METHODS

Web of Science, Scopus, and Ovid MEDLINE were searched for studies of humans born premature and/or of low birthweight, where neurodevelopmental phenotypes were measured at 1 year of age or older. Studies must have reported outcomes in such a way that it was possible to assess whether effects were greater in one sex than the other. Risk of bias was assessed using both the Newcastle-Ottawa scale and the National Institutes of Health Quality assessment tool for observational cohort and cross-sectional studies.

RESULTS

Seventy-five studies were included for descriptive synthesis, although only 24 presented data in a way that could be extracted for meta-analyses. Meta-analyses found that severe and moderate prematurity/low birthweight impaired cognitive function, and severe prematurity/low birthweight also increased internalizing problem scores. Moderate, but not severe, prematurity/low birthweight significantly increased externalizing problem scores. In no case did effects of prematurity/low birthweight differ between males and females. Heterogeneity among studies was generally high and significant, although age at assessment was not a significant moderator of effect. Descriptive synthesis did not identify an obvious excess or deficiency of male-biased or female-biased effects for any trait category. Individual study quality was generally good, and we found no evidence of publication bias.

CONCLUSIONS

We found no evidence that the sexes differ in their susceptibility to the effects of severe or moderate prematurity/low birthweight on cognitive function, internalizing traits or externalizing traits. Result heterogeneity tended to be high, but this reflects that one sex is not consistently more affected than the other. Frequently stated generalizations that one sex is more susceptible to prenatal adversity should be re-evaluated.

Associations Between Preterm Birth, Inhibitory Control-Implicated Brain Regions and Tracts, and Inhibitory Control Task Performance in Children: Consideration of Socioeconomic Context

Preterm birth (PTB) is associated with increased risk for unfavorable outcomes such as deficits in attentional control and related brain structure alterations. Crucially, PTB is more likely to occur within the context of poverty. The current study examined associations between PTB and inhibitory control (IC) implicated brain regions/tracts and task performance, as well as the moderating role of early life poverty on the relation between PTB and IC-implicated regions/tracts/task performance. 2,899 children from the ABCD study were sampled for this study. Mixed effects models examined the relation between PTB and subsequent IC performance as well as prefrontal gray matter volume, white matter fractional anisotropy (FA), and mean diffusivity (MD). Household income was examined as a moderator. PTB was significantly associated with less improvement in IC task performance over time and decreased FA in left uncinate fasciculus (UF) and cingulum bundle (CB). Early life poverty moderated the relation between PTB and both CB FA and UF MD.

Exposure of ambient PM2.5 during gametogenesis period affects the birth outcome: Results from the project ELEFANT

Various environmental and behavioural factors influence neonatal health. Gamete formation (gametogenesis) is a crucial period which affects embryo development and neonatal health and ambient air pollution exposure at this stage may lead to an adverse birth outcome. Previous epidemiological and toxicological research demonstrated a strong association between maternal ambient air pollution exposure and adverse birth outcomes. However, the joint exposure-outcome of paternal exposure (76 days before the last menstruation and 14 days after the last menstruation) and maternal exposure (14 days after the last menstruation) when exploring the mechanism of the influence of air pollutants on pregnancy outcome and neonatal health remains unexplored. Here, in the Project Environmental and LifEstyle FActors iN metabolic health throughout life-course Trajectories (ELEFANT), we collected the data of 10,960 singleton pregnant women with 24-42 completed gestational weeks and included them in this study. A multinominal logistic regression model was applied to investigate the association between adverse birth outcomes and ambient PM_2.5 exposure levels during spermatogenesis and oogenesis. Results from the binary classification of ambient PM_2.5 exposure showed that the risk of abnormal birthweight was significantly greater when ambient PM_2.5 exposure was both higher during spermatogenesis and oogenesis, with RRs of 1.86 (95% CI: 1.02, 3.39). The risk of macrosomia (RR: 1.88 (95% CI: 1.13, 3.12)) increased significantly when ambient PM_2.5 levels were higher during spermatogenesis. Primiparity and primigravity are more likely to be influenced by higher ambient PM_2.5 levels during spermatogenesis. In conclusion, more attention should be paid to higher exposure level of ambient PM_2.5 during spermatogenesis.

Basal Stimulation as Developmental Support in At-Risk Newborns: A Literature Review

BACKGROUND

The aim of this review of the literature was to find and summarize relevant research evidence available within the scientific sources and gray literature in accordance with the JBI recommendations. Search question: What effect does Basal Stimulation have on the cognitive-behavioral functions or temperament of a preterm or disabled infant?

METHODS

The following sources were searched: PSYCINFO, MEDLINE, PsycArticles, ERIC, Wiley Online Library, ProQuest Scopus, WOS, JSTOR, Google Scholar, and MedNar. The study contains an analysis of texts that have been published in the English, Czech, and German languages. The search time span was set at 15 years.

RESULTS

A total of 15 sources were found for the specified topic.

CONCLUSIONS

In all cases, there was confirmation about the positive influence of the concept of "Basal Stimulation" on the cognitive-behavioral functions and temperament of premature and disabled children.

Neuropsychological abilities underpinning academic attainment in children born extremely preterm

Children born extremely preterm (EP) have poorer academic attainment than their term-born peers. There is a need to identify the specific cognitive mechanisms that are associated with poor academic attainment in preterm populations to inform the development of intervention strategies. A parallel mediation analysis was conducted with cross-sectional data from 152 EP children (< 27 weeks of gestation) and 120 term-born controls who were assessed at age 11. Mathematics and reading attainment was assessed using the Wechsler Individual Achievement Test 2nd Edition. Controlling for sex and socio-economic status we evaluated the following mediators: verbal working memory, visuospatial working memory, verbal processing speed, attention, and visuospatial processing. These were assessed using subtests from the standardized NEPSY-II test and Wechsler Intelligence Scale for Children-5th Edition. Verbal working memory, visuospatial working memory, visuospatial processing and verbal processing speed, but not attention, were significant independent mediators between EP birth and attainment in reading. No direct relationship between EP birth and reading attainment remained in the mediated model. All five neuropsychological variables mediated the relationship between EP birth and attainment in mathematics, but a direct effect of EP birth on mathematics remained in the mediated model. Together, all five neuropsychological abilities indirectly explained 44% of the variance in reading and 52% of the variance in mathematics. Visuospatial processing was the strongest mediator of both mathematics and reading. Components of executive function, especially visuospatial processing, are important predictors of academic attainment. Interventions to improve visuospatial skills could be trialed in EP populations.

Etiology of persistent mathematics difficulties from childhood to adolescence following very preterm birth

Children born very preterm (VP; <32 weeks' gestation) have poorer mathematics achievement than term-born peers. This study aimed to determine whether VP children's mathematics difficulties persist from primary to secondary school and to explore the nature of mathematics difficulties in adolescence. For this study, 127 VP and 95 term-born adolescents were assessed at age 11-15 years. Mathematics achievement was assessed using the Wechsler Individual Achievement Test-II. Specific mathematics skills and general cognitive skills were assessed using standardized and experimental tests. VP adolescents had poorer mathematics achievement than term-born adolescents (-10.95 points; 95% CI -16.18, -5.73) and poorer number fact knowledge, understanding of arithmetic concepts, written arithmetic, counting, reading and writing large numbers, and algebra. Between-group differences in mathematics skills were no longer significant when working memory and visuospatial skills were controlled for (p's >0.05), with the exception of writing large numbers and conceptual understanding of arithmetic. In a previous study, 83 of the VP adolescents and 49 of the term-born adolescents were assessed at age 8-10 years using measures of the same skills. Amongst these, the between-group difference in mathematics achievement remained stable over time. This study extends findings of a persistent deficit in mathematics achievement among VP children over the primary and secondary school years, and provides evidence of a deficit in factual, procedural and conceptual mathematics skills and in higher order mathematical operations among VP adolescents. We provide further evidence that VP children's mathematics difficulties are driven by deficits in domain-general rather than domain-specific cognitive skills.

Self-regulation task in young school age children born preterm: Correlation with early academic achievement

BACKGROUND

Children born preterm are at risk for difficulties in executive function (EF), however there are limited tools to assess EF in young children and it is not fully understood how these early deficits are related to emerging academic skills.

AIMS

To examine (a) early EF differences in young children born preterm, (b) how a measure of behavioral self-regulation correlates with other measures of EF in children born preterm, and (c) how this measure relates to academic outcomes in children born preterm.

STUDY DESIGN

Longitudinal cohort study.

SUBJECTS

Thirty-three healthy children born preterm (25-32 weeks gestation) and 14 children born full term were assessed before starting kindergarten at age 5 and again at ages 6 and 7 years.

OUTCOME MEASURES

Each assessment included a measure of behavioral self-regulation, the Head Toes Knees Shoulders task (HTKS), performance-based measures of EF, parent rating scales of EF and behavior problems, a measure of motor ability, and academic measures.

RESULTS

Children born preterm performed worse on all measures of self-regulation, EF, parent-report, academic outcomes, and motor ability across time. The HTKS had weak to moderate correlations with parent-report and performance-based measures of EF, moderate to strong correlations with academic performance, and was not correlated with motor ability.

CONCLUSION

This study shows the predictive value of early EF measures on functional academic outcomes and their potential as targets of effective interventions in this high-risk population.

Perceived stress may mediate the relationship between antenatal depressive symptoms and preterm birth: A pilot observational cohort study

Background

Screening for changes in pregnancy-related anxiety and depressive symptoms during pregnancy may further our understanding of the relationship between these two variables and preterm birth.

Objectives

To determine whether changes in pregnancy-related anxiety and depressive symptoms during pregnancy influence the risk of preterm birth among Pakistani women; explore whether perceived stress moderates or mediates this relationship, and examine the relationship between the various components of pregnancy-related anxiety and preterm birth.

Methods

A prospective cohort study design was used to recruit a diverse sample of 300 low-risk pregnant women from four centers of Aga Khan Hospital for Women and Children in Karachi, Pakistan. Changes in pregnancy-related anxiety and depressive symptoms during pregnancy were tested. Multiple logistic regression analysis was used to determine a predictive model for preterm birth. We then determined if the influence of perceived stress could moderate or mediate the effect of depressive symptoms on preterm birth.

Results

Changes in pregnancy-related anxiety (OR = 1.1, CI 0.97–1.17, p = 0.167) and depressive symptoms (OR = 0.9, CI 0.85–1.03, p = 0.179) were insignificant as predictors of preterm birth after adjusting for the effects of maternal education and family type. When perceived stress was added into the model, we found that changes in depressive symptoms became marginally significant after adjusting for covariates (OR = 0.9, CI 0.82–1.01, p = 0.082). After adjusting for the mediation effect of change in perceived stress, the effect of change in depressive symptoms on preterm birth were marginally significant after adjusting for covariates. Among six different dimensions of pregnancy-related anxiety, mother’s concerns about fetal health showed a trend towards being predictive of preterm birth (OR = 1.3, CI 0.97–1.72, p = 0.078).

Conclusions

There may be a relationship between perceived stress and antenatal depressive symptoms and preterm birth. This is the first study of its kind to be conducted in Pakistan. Further research is required to validate these results.