Development of executive functions from childhood to adolescence in very preterm-born individuals - A longitudinal study

Executive function and preterm birth: A longitudinal study

Infants born low birth weight (LBW) and preterm are at risk for developmental delay and cognitive deficits. These deficits can lead to lifelong learning difficulties and high-risk behaviors. Preterm (PT) and full-term (FT) groups were compared across infant and toddler measures of behavior and development to extract early indicators of executive function (EF). The goal was to extract indicators of EF from standardized infant assessments. PT (<2500 grams and <37 weeks) and FT (> 2500 grams and >37 weeks) were compared across assessment and EF components were identified from the BSID-III. A multivariate linear model was used to examine group differences. All children (99 PT and 46 FT) were administered the Bayley III and the DMQ assessments for session 1 (6-8 months). During session 2, N=78 PT and 37 FT (18-20 months), the CBCL was added to previous assessments, and the BRIEF-P was added to previous assessments in session 3, N= 52 PT and 36 FT for session 3 (See Table 1). Significant change scores were found on BSID-III subtests and EF components across all 3 sessions. The PT group also showed significantly more behavioral concerns on the CBCL at 18 months and 36 months and had lower scores on the BRIEF-P than their FT peers. The number of children born PT (N = 27, 52%) who were in Early Intervention (EI) increased across the 3 sessions. Examining early indicators of EFs supported the development of early identification that could lead to decrease adverse outcomes often associated with preterm birth.

Stability of executive function in children born at risk of neonatal hypoglycemia

Executive function plays an important role in promoting learning and social-emotional development in children. Neonatal hypoglycemia associates with executive function difficulties at 4.5 years, but little is known about the development of executive function over time in children born at risk of neonatal hypoglycemia. We aimed to describe the stability of executive function from early to mid-childhood in children born at risk of neonatal hypoglycemia and its association with neonatal hypoglycemia. Participants in a prospective cohort study of infants born at risk for neonatal hypoglycemia were assessed at ages 2, 4.5, and 9-10 years. We assessed executive function with batteries of performance-based and questionnaire-based measures, and classified children into one of four stability groups (persistent typical, intermittent typical, intermittent difficulty, and persistent difficulty) based on dichotomized scores (typical versus low at each age). Multinomial logistic regression was used to determine the associations between neonatal hypoglycemia and executive function stability groups. Three hundred and nine children, of whom 197 (64%) experienced neonatal hypoglycemia were assessed. The majority of children had stable and typical performance-based (63%) and questionnaire-based (68%) executive function across all three ages. Around one-third (30-36%) of children had transient difficulties, and only a few (0.3-1.9%) showed persistent difficulties in executive function at all ages. There was no consistent evidence of an association between neonatal hypoglycemia and the stability of executive function. Neonatal hypoglycemia does not appear to predict a specific pattern of development of executive function in children born at risk.

Family resiliency and family functioning in Non-Hispanic Black and Non-Hispanic White families of preterm infants

PURPOSE

The purpose of this study was to examine the relationship between resiliency factors and family functioning in families of preterm infants (< 37 weeks gestation) from two different racial groups hospitalized in a neonatal intensive care unit (NICU).

DESIGN AND METHODS

A cross-sectional design was used at five Level III/IV NICUs in a Midwestern city/suburbs. Seventy-nine family units (24 Non-Hispanic Black and 55 Non-Hispanic White) completed four instruments that assessed families' use of specific resiliency factors and a measure of family functioning. Demographic data were also collected.

RESULTS

Using linear mixed modeling, the significant predictors of family functioning for both Non-Hispanic Black and Non-Hispanic White, even after adjusting for education, income and race, were the protective factors "hardiness" (coefficient = -0.021) and "resources" (coefficient = -0.0052). The fixed effects in the model accounted for 48% (Marginal R² = 0.48) of the variance on family functioning and the fixed and random effects accounted for 59% (Conditional R^2, 0.59) of the variance on family functioning. Sixteen percent of the total sample rated their family as dysfunctional.

CONCLUSIONS

Findings from this study suggest that assessment of protective factors related to hardiness and resources individualize nursing interventions to support the resiliency of both Non-Hispanic Black and Non-Hispanic White families, regardless of differences in income and education. Further research studying resiliency in families of preterm infants is needed to understand the impact on long-term family functioning.

PRACTICE IMPLICATIONS

Understandingindividual family strengths,through the identification of resiliency (protective and recovery) factors could predict at-risk families before discharge. In collaboration with other health care professionals, nurses can assess individual family needs and strengths, within the context of their socioeconomic environment, and the racial and cultural influences that are important to the family.

Cognitive outcome is related to functional thalamo-cortical connectivity after pediatric stroke

The thalamus has complex connections with the cortex and is involved in various cognitive processes. Despite increasing interest in the thalamus and the underlying thalamo-cortical interaction, little is known about thalamo-cortical connections after pediatric arterial ischemic stroke. Therefore, the aim of this study was to investigate thalamo-cortical connections and their association with cognitive performance after arterial ischemic stroke.

Twenty patients in the chronic phase after pediatric arterial ischemic stroke (≥ 2 years after diagnosis, diagnosed &lt;16 years; aged 5–23 years, mean 15.1 years) and twenty healthy controls matched for age and sex were examined in a cross-sectional study design. Cognitive performance (selective attention, inhibition, working memory, and cognitive flexibility) was evaluated using standardized neuropsychological tests. Resting-state functional magnetic resonance imaging was used to examine functional thalamo-cortical connectivity. Lesion masks were integrated in the preprocessing pipeline to ensure that structurally damaged voxels did not influence functional connectivity analyses.

Cognitive performance (selective attention, inhibition and working memory) was significantly reduced in patients compared to controls. Network analyses revealed significantly lower thalamo-cortical connectivity for the motor, auditory, visual, default mode network, salience, left/right executive and dorsal attention network in patients compared to controls. Interestingly, analyses revealed as well higher thalamo-cortical connectivity in some subdivisions of the thalamus for the default mode network (medial nuclei), motor (lateral nuclei), dorsal attention (anterior nuclei), and the left executive network (posterior nuclei) in patients compared to controls. Increased and decreased thalamo-cortical connectivity strength within the same networks was, however, found in different thalamic sub-divisions. Thus, alterations in thalamo-cortical connectivity strength after pediatric stroke seem to point in both directions, with stronger as well as weaker thalamo-cortical connectivity in patients compared to controls. Multivariate linear regression, with lesion size and age as covariates, revealed significant correlations between cognitive performance (selective attention, inhibition, and working memory) and the strength of thalamo-cortical connectivity in the motor, auditory, visual, default mode network, posterior default mode network, salience, left/right executive, and dorsal attention network after childhood stroke.

Our data suggest that the interaction between different sub-nuclei of the thalamus and several cortical networks relates to post-stroke cognition. The variability in cognitive outcomes after pediatric stroke might partly be explained by functional thalamo-cortical connectivity strength.

Effects of Correcting for Prematurity on Executive Function Scores of Children Born Very Preterm at School Age

OBJECTIVE

To investigate whether correction for prematurity affects executive function scores in school-aged children born very preterm.

STUDY DESIGN

Executive functions were assessed with standardized neuropsychological tests in 142 children born very preterm (born at ≤32 weeks of gestational age or with a birth weight of ≤1500 g) and 391 control children, aged 7-13 years. Four-month age bands were established from the data of control children. Differences between uncorrected and corrected scores were compared against zero difference and between very preterm children born before and after 28 weeks of gestation. Regression models were used to compare the uncorrected and corrected scores of children born very preterm with control children.

RESULTS

For all executive functions, significant, larger-than-zero differences between uncorrected and corrected scores were apparent in children born very preterm. Mean differences ranged from 0.04 to 0.18 SDs. Weak evidence was found that the effect of age correction is more pronounced in very preterm children born before 28 weeks of gestation than in those born after 28 weeks. Differences in executive function scores between children born very preterm and control children were attenuated if scores were corrected for prematurity.

CONCLUSIONS

Test scores based on corrected rather than uncorrected age may more accurately determine the developmental stage of very preterm children's executive functions at school age. Potential consequences for clinical and research practice need to be discussed in the future.

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.

Early working memory is a significant predictor of verbal and processing skills at 6-7 years in children born extremely preterm

OBJECTIVE

The study was designed to investigate whether attainment of object permanence, a measure of early working memory used at 18-22 months corrected age, was associated with executive function at 6-7 years in a cohort of children born extremely preterm.

STUDY DESIGN

Children enrolled in the Neuroimaging and Neurodevelopmental Outcome (NEURO) study, a secondary study to the Surfactant Positive Airway Pressure and Pulse Oximetry Trial (SUPPORT) of the NICHD NRN, were eligible for this longitudinal study. Testing completed at 18 to 22 months corrected age was compared to testing at school age with a specific focus on measures of executive function.

RESULTS

Children who had achieved object permanence mastery at a corrected age of 18-22 months had higher mean scores on the WISC-IV tests of verbal comprehension and processing speed at age 6-7 years. Regression models indicated that object permanence scores were significant predictors of both verbal comprehension and processing speeds scores, after controlling for other factors. When analyzed by subgroup for sex, these results were significant for girls but not for boys.

CONCLUSIONS

This study found that an early mastery of object permanence was associated with higher scores in areas of verbal comprehension and processing speed in girls. These results have implications for potentially identifying young children born preterm that are at greater risk for difficulties with cognitive and working memory skills at school age.

Inhibition is associated with whole-brain structural brain connectivity on network level in school-aged children born very preterm and at term

Inhibition abilities are often impaired in children born very preterm. In typically-developing individuals, inhibition has been associated with structural brain connectivity (SC). As SC is frequently altered following preterm birth, this study investigated whether aberrant SC underlies inhibition deficits in school-aged children born very preterm. In a group of 67 very preterm participants aged 8-13 years and 69 term-born peers, inhibition abilities were assessed with two tasks. In a subgroup of 50 very preterm and 62 term-born participants, diffusion tensor imaging (DTI) data were collected. Using network-based statistics (NBS), mean fractional anisotropy (FA_mean) was compared between groups. Associations of FA_mean and inhibition abilities were explored through linear regression. The composite score of inhibition abilities was lower in the very preterm group (M ​= ​-0.4, SD ​= ​0.8) than in the term-born group (M ​= ​0.0, SD ​= ​0.8) but group differences were not significant when adjusting for age, sex and socio-economic status (β ​= ​-0.13, 95%-CI [-0.30, 0.04], p ​= ​0.13). In the very preterm group, FA_mean was significantly lower in a network comprising thalamo-frontal, thalamo-temporal, frontal, cerebellar and intra-hemispheric connections than in the term-born group (t ​= ​5.21, lowest p-value ​= ​0.001). Irrespective of birth status, a network comprising parietal, cerebellar and subcortical connections was positively associated with inhibition abilities (t ​= ​4.23, lowest p-value ​= ​0.02). Very preterm birth results in long-term alterations of SC at network-level. As networks underlying inhibition abilities do not overlap with those differing between the groups, FA_mean may not be adequate to explain inhibition problems in very preterm children. Future studies should combine complementary measures of brain connectivity to address neural correlates of inhibition abilities.

Patterns of sociocognitive stratification and perinatal risk in the child brain

The expanding behavioral repertoire of the developing brain during childhood and adolescence is shaped by complex brain-environment interactions and flavored by unique life experiences. The transition into young adulthood offers opportunities for adaptation and growth but also increased susceptibility to environmental perturbations, such as the characteristics of social relationships, family environment, quality of schools and activities, financial security, urbanization and pollution, drugs, cultural practices, and values, that all act in concert with our genetic architecture and biology. Our multivariate brain-behavior mapping in 7,577 children aged 9 to 11 y across 585 brain imaging phenotypes and 617 cognitive, behavioral, psychosocial, and socioeconomic measures revealed three population modes of brain covariation, which were robust as assessed by cross-validation and permutation testing, taking into account siblings and twins, identified using genetic data. The first mode revealed traces of perinatal complications, including preterm and twin birth, eclampsia and toxemia, shorter period of breastfeeding, and lower cognitive scores, with higher cortical thickness and lower cortical areas and volumes. The second mode reflected a pattern of sociocognitive stratification, linking lower cognitive ability and socioeconomic status to lower cortical thickness, area, and volumes. The third mode captured a pattern related to urbanicity, with particulate matter pollution (PM²⁵) inversely related to home value, walkability, and population density, associated with diffusion properties of white matter tracts. These results underscore the importance of a multidimensional and interdisciplinary understanding, integrating social, psychological, and biological sciences, to map the constituents of healthy development and to identify factors that may precede maladjustment and mental illness.

Development of egocentric and allocentric spatial orientation abilities in children born preterm with very low birth weight

BACKGROUND

Very low birth weight preterm infants show neuropsychological alterations in functions such as memory or visuospatial skills, although certain related functions, such as spatial orientation, have not been studied.

OBJECTIVES

To compare children born preterm and at term between the ages of 5 and 7 years on egocentric and allocentric spatial orientation, and relate their performance to visuospatial skills, behavior, memory in daily environments, and perinatal risk factors.

STUDY DESIGN

Observational cross-sectional study.

SUBJECTS

88 very low birth weight children born preterm and 59 controls.

OUTCOME MEASURES

IQ (RIST), visuospatial skills (NEPSY II: Route Finding and Geometric Puzzles), spatial orientation (Egocentric and Allocentric Spatial Memory Test - Children's Version), behavior (BASC questionnaire for parents), memory in everyday environments (ECM-Q questionnaire for parents), and perinatal risk factors (collected from medical records).

RESULTS

Children born preterm obtain significantly lower scores than controls on the RIST, Route Finding, and Allocentric Spatial Memory Tests. Although spatial orientation is related to other neuropsychological variables in both premature and control children, there is no meaningful association with behavior or daily memory in children born preterm. The perinatal risk factors that are associated the most with visuospatial and orientation problems are surgical procedures and peri- and intraventricular hemorrhages.

CONCLUSIONS

Children born preterm with low birth weight present difficulties in their spatial orientation, and for this reason, we propose including these types of tasks in the usual neuropsychological evaluation.