Early working memory as a racially and ethnically neutral measure of outcome in extremely preterm children at 18-22 months

Early developmental trajectory of children with prenatal alcohol and opioid exposure

BACKGROUND

With significant increases in opioid use/misuse and persistent high prevalence of prenatal alcohol exposure (PAE), identifying infants at risk for long-term developmental sequelae due to these exposures remains an urgent need. This study reports on developmental outcomes in young children from a prospective cohort, ENRICH-1, which recruited pregnant women and followed up maternal-infant pairs.

METHODS

Subjects were assigned to four study groups based on prenatal use of medications for opioid use disorder (MOUD), PAE, MOUD+PAE, and unexposed controls (UC). Mixed effects modeling was used to evaluate changes in the Bayley Scales of Infant Development-III (BSID-III) Cognitive, Language, and Motor scores between 6 and 20 months.

RESULTS

There was a significant three-way interaction (MOUD-by-PAE-by-Time) with respect to the BSID-III Cognitive (p = 0.045) and Motor (p = 0.033) scales. Significant changes between the two evaluations were observed for MOUD group in Cognitive and Language scores; for PAE group in Cognitive, Language, and Motor scores, and for MOUD+PAE group in Language scores after adjusting for child sex and family socio-economic status. The developmental scores for the UC remained stable.

CONCLUSION

Observed decline in neurodevelopmental scores during the first 2 years of life emphasizes the importance of a longitudinal approach when evaluating children with prenatal polysubstance exposure.

IMPACT

BSID-III scores were stable during the first 2 years of life for unexposed children. BSID-III scores declined for children with prenatal exposures to alcohol and/or opioids. Standard developmental tests may not be sensitive enough during the first year of life. Findings emphasize the need for repeated evaluations of children who are at high risk.

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.

Early neurodevelopmental follow-up in the NICHD neonatal research network: Advancing neonatal care and outcomes, opportunities for the future

At the inception of the Eunice Kennedy Shriver National Institute of Child Health and Development Neonatal Research Network (NRN), provision of care for extremely preterm (EPT) infants was considered experimental. The NRN Follow-up Study Group, initiated in 1993, developed infrastructure with certification processes and standards, allowing the NRN to assess 2-year outcomes for EPT and to provide important metrics for randomized clinical trials. This chapter will review the NRN Follow-up Study Group's contributions to understanding factors related to improved neurodevelopmental, behavioral, and social-emotional outcomes of EPT infants. We will also discuss follow up challenges, including reassessing which outcomes are most meaningful for parents and investigators. Finally, we will explore how outcome studies have informed clinical decisions and ethical considerations, given limitations of prediction of complex later childhood outcomes from early neurodevelopmental findings.

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.

Lack of social support as measured by the Family Resource Scale screening tool is associated with early adverse cognitive outcome in extremely low birth weight children

OBJECTIVE

Extremely low birth weight children are at high risk for cognitive impairment.

STUDY DESIGN

Cognitive outcome of extremely low birth weight children participating in a Neonatal Research Network, randomized trial was evaluated at 18 and 30 months corrected age using the Bayley Scales of Infant Development, 2nd ed. Family resources and social support were assessed using a Family Resource Scale parent questionnaire. Regression analysis was used to determine independent demographic, medical, and family resource factors influencing longitudinal cognitive outcome.

RESULT

Higher Family Resource Scale scores at 18 months were associated with greater improvement in cognitive scores between 18 and 30 months. Cognitive outcome was most adversely affected in children whose families had the least resources and social support. The adverse effect of poor social support was independent of family income.

CONCLUSION

Poor interpersonal social support has an independent, adverse impact on cognitive outcomes of extremely low birth weight infants.

Hypoxia of Rats Subjected to Carotid Artery Ligation Results in Impaired Neurogenesis and Reduced Number of Cortical Neurons

BACKGROUND/AIM

Cerebral ischemia is a major cause of abnormal brain development. In a cerebral ischemia model, periventricular leukomalacia (PVL), white matter lesion and a decrease in the number of subcortical neurons were observed. The aim of this study was to investigate the effect of hypoxia on neurogenesis and cell survival.

MATERIALS AND METHODS

In seven-day postnatal rats, the right carotid artery was ligated. The rats were incubated either in a regular normoxic chamber (control group) or in a hypoxic chamber (PVL group, 8% 02 and 92% N2 at 37°C) for 2 h. Nestin- and NeuN-positive neurons were detected by immunohistochemistry.

RESULTS

The densities of nestin-immunoreactivity (IR) cells in the cerebral parietal cortex and subventricular zone were increased with hypoxia. NeuN-IR cells in the cerebral cortex were significantly decreased in the PVL group.

CONCLUSION

Perinatal white matter injury induced neurogenesis, while the survival of neurons was decreased in the cerebral cortex.

Behavior problems and executive function impairments in preterm compared to full term preschoolers

BACKGROUND

Children born preterm (PT) are at high risk for behavior problems and deficits in executive function (EF), a set of cognitive processes that guide goal-directed behaviors. Behavior differences have been found as early as 2 years in PT children; EF differences have been found in infancy. Whether behavior problems and EF deficits co-occur at young ages has not been fully investigated.

AIMS

To determine whether (1) PT children have more behavior problems and EF impairment than full term (FT) children and (2) larger proportions of PT children show behavior problems or EF impairments.

DESIGN/METHODS

PT (≤34 wks, n = 82) and FT (n = 79) preschoolers (mean age 4.4 years) completed an EF battery. Parents completed rating scales of behavior problems and EF skills. Mean scores and proportions with impairment were compared between groups. Logistic regression predicting to impairment defined odds ratios for PT/FT groups.

RESULTS

PT compared to FT had more problems on most behavior and EF scales and poorer EF scores on all tasks and greater proportion with impairments on most behavior scales, all EF ratings, and all EF tasks, p < .05. PT had elevated odds for impaired performance-based EF, parent-rated EF and CBCL scores compared to FT, p < .05. Within the PT group, EF impairments were twice as common as behavior impairment.

CONCLUSIONS

We recommend early identification of EF impairments in PT children. Future research should evaluate whether EF impairments serve as better early markers for later functional difficulties compared to behavior problems, as well as targets for intervention.

Cognitive Development and Quality of Life Associated With BPD in 10-Year-Olds Born Preterm

OBJECTIVES

To compare neurocognitive, language, executive function, academic achievement, neurologic and behavioral outcomes, and quality of life at age 10 years in children born extremely preterm who developed bronchopulmonary dysplasia (BPD) to children who did not develop BPD.

METHODS

The Extremely Low Gestational Age Newborns study population included 863 children born extremely preterm whose BPD status before discharge was known had an IQ (Differential Ability Scales II [DAS II]) assessment at 10 years. We evaluated the association of BPD with any cognitive (DAS II), executive function (NEuroPSYchological Assessment II), academic achievement (Wechsler Individual Achievement Test-III and Oral and Written Language Scales [OWLS]) as well as social dysfunctions (Social Responsiveness Scale). We used logistic regression models, adjusting for potential confounding factors, to assess the strength of association between the severity of BPD and each outcomes.

RESULTS

Three hundred and seventy-two (43%) children were oxygen-dependent at 36 weeks postconception age, whereas an additional 78 (9%) were also oxygen- and ventilator-dependent. IQ scores 2 or more SDs below the expected mean (ie, z scores ≤-2) occurred twice as commonly among children who had BPD as among those who did not. Children with severe BPD consistently had the lowest scores on DAS II, OWLS, Wechsler Individual Achievement Test-III, NEuroPSYchological Assessment II, and Social Responsiveness Scale assessments.

CONCLUSIONS

Among 10-year-old children born extremely preterm, those who had BPD were at increased risk of cognitive, language, and executive dysfunctions; academic achievement limitations; social skill deficits; and low scores on assessments of health-related quality of life.

Extremely preterm children exhibit increased interhemispheric connectivity for language: findings from fMRI-constrained MEG analysis

Children born extremely preterm are at significant risk for cognitive impairment, including language deficits. The relationship between preterm birth and neurological changes that underlie cognitive deficits is poorly understood. We use a stories-listening task in fMRI and MEG to characterize language network representation and connectivity in children born extremely preterm (n = 15, <28 weeks gestation, ages 4-6 years), and in a group of typically developing control participants (n = 15, term birth, 4-6 years). Participants completed a brief neuropsychological assessment. Conventional fMRI analyses revealed no significant differences in language network representation across groups (p > .05, corrected). The whole-group fMRI activation map was parcellated to define the language network as a set of discrete nodes, and the timecourse of neuronal activity at each position was estimated using linearly constrained minimum variance beamformer in MEG. Virtual timecourses were subjected to connectivity and network-based analyses. We observed significantly increased beta-band functional connectivity in extremely preterm compared to controls (p < .05). Specifically, we observed an increase in connectivity between left and right perisylvian cortex. Subsequent effective connectivity analyses revealed that hyperconnectivity in preterms was due to significantly increased information flux originating from the right hemisphere (p < 0.05). The total strength and density of the language network were not related to language or nonverbal performance, suggesting that the observed hyperconnectivity is a "pure" effect of prematurity. Although our extremely preterm children exhibited typical language network architecture, we observed significantly altered network dynamics, indicating reliance on an alternative neural strategy for the language task.

Preschool Assessment of Preterm Infants Treated With Darbepoetin and Erythropoietin

BACKGROUND

We previously reported improved neurodevelopmental outcomes at 2 years among infants treated with the erythropoiesis-stimulating agents (ESAs) darbepoetin alfa (darbepoetin) or erythropoietin. Here we characterize 4-year outcomes.

METHODS

Former preterm infants randomly assigned to receive darbepoetin (10 μg/kg, once per week), erythropoietin (400 U/kg, 3 times/week), or placebo through 35 weeks' postconceptual age were evaluated at 3.5 to 4 years of age. For comparison, healthy children formerly delivered full term (term controls [TCs]) were also recruited. All participants were assessed by using measures of full-scale IQ (FSIQ) and general language from the Wechsler Preschool and Primary Scale of Intelligence, Third Edition, and an overall measure of executive function, on the basis of tests evaluating inhibitory control and spatial working memory. Rates of neurodevelopmental impairment were compared across groups.

RESULTS

Multivariate analysis of variance compared children randomly assigned to ESAs (n = 39), placebo (n =14), and TCs (n = 24). FSIQ and performance IQ were significantly higher in the ESA group than in the placebo group (FSIQ: 91.1 ± 17.5 vs 79.2 ± 18.5, P = .036; performance IQ: 93.0 ± 17.0 vs 79.5 ± 19.5, P = .018). Follow-up analyses revealed that the children receiving ESAs performed better than those who received placebo on executive function tasks. The ESA group's performance was below that of TCs, but the results did not reach significance on executive function. The incidence of neurodevelopmental impairment was greater in the placebo group than in the ESA group.

CONCLUSIONS

ESA-treated infants had better cognitive outcomes and less developmental impairment at 3.5 to 4 years of age compared with placebo-treated infants. ESAs show promise in improving long-term cognitive outcomes of infants born prematurely.

Ethanol, Neurodevelopment, Infant and Child Health (ENRICH) prospective cohort: Study design considerations

BACKGROUND

While intervention is the leading factor in reducing long-term disabilities in children with fetal alcohol spectrum disorder (FASD), early identification of children affected by prenatal alcohol exposure (PAE) remains challenging. Deficits in higher-order cognitive domains (e.g. executive function) might be more specific to FASD than global neurodevelopmental tests, yet these functions are not developed in very young children. Measures of early sensorimotor development may provide early indications of atypical brain development during the first two years of life.

METHODS

This paper describes the novel methodology of the Ethanol, Neurodevelopment, Infant and Child Health (ENRICH) prospective cohort study of 120 maternal-infant pairs with a goal to identify early indices of functional brain impairment associated with PAE. The cohort is established by recruiting women early in pregnancy and classifying them into one of three study groups: patients on opioid-maintenance therapy who consume alcohol during pregnancy (Group 1), patients on opioid-maintenance therapy who abstain from alcohol during pregnancy (Group 2), and healthy controls (Group 3). After the initial prenatal assessment (Visit 1), patients are followed to Visit 2 occurring at delivery, and two comprehensive assessments of children at six (Visit 3) and 20 months (Visit 4) of age. ENRICH recruitment started in November 2013 and 87 women were recruited during the first year. During Year 1, the biospecimen (maternal whole blood, serum, urine, dry blood spots of a newborn) collection rate was 100% at Visit 1, and 97.6% for those who completed Visit 2.

DISCUSSION

The tiered screening approach, evaluation of confounders, neurocognitive and magneto-/electro-encephalography (MEG/EEG) outcomes, and ethical considerations are discussed.

Associations between maternal scaffolding and executive functioning in 3 and 4 year olds born very low birth weight and normal birth weight

BACKGROUND

Deficits in executive function, including measures of working memory, inhibition and cognitive flexibility, have been documented in preschoolers born very low birth weight (VLBW) compared with preschoolers born normal birth weight (NBW). Maternal verbal scaffolding has been associated with positive outcomes for both at-risk and typically developing preschoolers.

AIMS

The purpose of this study was to examine associations between maternal verbal scaffolding, Verbal IQ (VIQ) and executive function measures in preschoolers born VLBW.

SUBJECTS

A total of 64 VLBW and 40 NBW preschoolers ranging in age from 3 ½ to 4 years participated in the study.

OUTCOME MEASURES

VIQ was measured with the Wechsler Preschool and Primary Scale of Intelligence - Third Edition. Executive function tests included the Bear Dragon, Gift Delay Peek, Reverse Categorization and Dimensional Change Card Sort-Separated Dimensions.

STUDY DESIGN

Maternal verbal scaffolding was coded during a videotaped play session. Associations between maternal verbal scaffolding and preschoolers' measures of VIQ and executive function were compared. Covariates included test age, maternal education, and gender.

RESULTS

Preschoolers born VLBW performed significantly worse on VIQ and all executive function measures compared to those born NBW. Maternal verbal scaffolding was associated with VIQ for VLBW preschoolers and Gift Delay Peek for the NBW group. Girls born VLBW outperformed boys born VLBW on VIQ and Bear Dragon.

CONCLUSION

Integrating scaffolding skills training as part of parent-focused intervention may be both feasible and valuable for early verbal reasoning and EF development.