Learning disabilities in children with very low birthweight: prevalence, neuropsychological correlates, and educational interventions

Low and very low birthweight disadvantage in compulsory education achievement and the transition to upper secondary education in the Finnish birth cohorts of 1987 to 1997

BACKGROUND

We compared the educational achievements of very low-birthweight (VLBW) and low-birthweight (LBW) adolescents (ages 16 to 19) to those of their normal-birthweight (NBW) peers in the complete Finnish birth cohorts of 1987 to 1997. We focused on three key phases of the education process: the end of compulsory education (9th-grade completion), and the transition to and the completion of upper secondary-level education.

METHODS

We used register data on grades, educational transitions and completed education. We employed multiple indicators on the progression of the education process and estimated population-level and within-families linear probability (LPM) models with robustness checks at the population level using logistic regression. We tested whether parental education and the child's sex modify the association between (V)LBW and educational achievement.

RESULTS

Results of both descriptive analysis and the population-level and within-family LPM models indicate that (V)LBW is associated with an increased risk of not being able to keep up with the normative education process and to compete for upper secondary education study places at the end of compulsory education. The modifying effect of parental education was robust, whereas that of the child's sex was not. Among (V)LBW students who were able to keep up with the normative education process, (V)LBW was not associated with a lower grade point average or with a meaningfully lower probability of completing upper secondary education by the normative age.

CONCLUSIONS

The upper secondary-level educational choices and achievements of the children born with (V)LBW who managed to complete the standard compulsory education curriculum and complete the transition to upper secondary-level education within the expected time did not, in essence, differ from those of the NBW children. Some specific characteristics of the Finnish education system likely contributed to these results, such as the grading at compulsory education being only relatively loosely standardized.

Necrostatin-1s Suppresses RIPK1-driven Necroptosis and Inflammation in Periventricular Leukomalacia Neonatal Mice

Periventricular leukomalacia (PVL), a predominant form of brain injury in preterm survivors, is characterized by hypomyelination and microgliosis and is also the major cause of long-term neurobehavioral abnormalities in premature infants. Receptor-interacting protein kinase 1 (RIPK1) plays a pivotal role in mediating cell death and inflammatory signaling cascade. However, very little is known about the potential effect of RIPK1 in PVL and the underlying mechanism. Herein, we found that the expression level of RIPK1 was drastically increased in the brain of PVL neonatal mice models, and treatment of PVL neonatal mice with Necrostatin-1s (Nec-1s), an inhibitor of RIPK1, greatly ameliorated cerebral ischemic injury, exhibiting an increase of body weights, reduction of cerebral infarct size, neuronal loss, and occurrence of necrosis-like cells, and significantly improved the long-term abnormal neurobehaviors of PVL. In addition, Nec-1s significantly suppressed hypomyelination and promoted the differentiation of oligodendrocyte precursor cells (OPCs), as demonstrated by the increased expression levels of MBP and Olig2, the decreased expression level of GPR17, a significant increase in the number of CC-1-positive cells, and suppression of myelin ultrastructure impairment. Moreover, the mechanism of neuroprotective effects of Nec-1s against PVL is closely associated with its suppression of the RIPK1-mediated necrosis signaling molecules, RIPK1, PIPK3, and MLKL. More importantly, inhibition of RIPK1 could reduce microglial inflammatory injury by triggering the M1 to M2 microglial phenotype, appreciably decreasing the levels of M1 marker CD86 and increasing the levels of M2 markers Arg1 or CD206 in PVL mice. Taken together, inhibition of RIPK1 markedly ameliorates the brain injury and long-term neurobehavioral abnormalities of PVL mice through the reduction of neural cell necroptosis and reversing neuroinflammation.

Industrial air pollution and low birth weight in New Mexico, USA

In recent decades, the low birth weight (LBW) rate in New Mexico has consistently exceeded the Unites States average. Maternal exposure to air pollution during pregnancy may be a significant contributor to LBW in offspring. This study investigated the links between maternal residential exposure to air pollution from industrial sources and the risk of LBW in offspring. The analysis included 22,375 LBW cases and 233,340 controls. It focused on 14 common chemicals listed in the Toxic Release Inventory (TRI) and monitoring datasets, which have abundant monitoring samples. The Emission Weighted Proximity Model (EWPM) was used to calculate maternal air pollution exposure intensity. Adjusted odds ratios (adjORs) were calculated using binary logistic regressions to examine the association between maternal residential air pollution exposure and LBW, while controlling for potential confounders, such as the maternal age, race/ethnicity, gestational age, prenatal care, education level, consumption of alcohol during pregnancy, public health regions, child's sex, and the year of birth. Multiple comparison correction was applied using the False Discovery Rate approach. The results showed that maternal residential exposure to 1,2,4-trimethylbenzene, benzene, chlorine, ethylbenzene, and styrene had significant positive associations with LBW in offspring, with adjusted odds ratios ranging from 1.10 to 1.13. These five chemicals remained as significant risk factors after dividing the estimated exposure intensities into four categories. In addition, significant linear trends were found between LBW and maternal exposure to each of the five identified chemicals. Furthermore, 1,2,4-trimethylbenzene was identified as a risk factor to LBW for the first time. The findings of this study should be confirmed through additional epidemiological, biological, and toxicological studies.

Physical fitness trajectories from childhood to adolescence in extremely preterm children: A longitudinal cohort study

OBJECTIVE

Cohort studies on physical fitness (PF) in former extremely preterm children are scarce and yield conflicting results. Therefore, this study aimed to assess the effect of extremely preterm birth on PF in school-age with a focus on bronchopulmonary dysplasia (BPD).

METHODS

Eighty school-aged children were enrolled in the longitudinal cohort study. Fifty were born extremely preterm (<completed 28 weeks of gestation): 19 had BPD, and 31 did not; 30 term-born healthy children were included as controls. They were monitored annually throughout primary school (ages 7-14 years) with eight annual fitness testings within the Slovenian national surveillance system of children's somatic and motor development (SLOfit). The physical fitness index (PFI), calculated as the mean of percentiles of eight fitness tests, was used as an indicator of overall PF. Generalised estimating equations were used to compare changes in PFI between ages 7 and 14 in the three cohort groups: preterm children with BPD, preterm children without BPD and term controls.

RESULTS

Preterm children with BPD had significantly and persistently lower PFI than preterm children without BPD and term-born children throughout primary school age. Their PFI was less than half that of national median values (15.1st-19.7th percentile). Preterm children without BPD experienced progressive improvement in PFI during their school age (from 32.6th to 44.7th percentile of national median PFI values), while the ones with BPD did not.

CONCLUSION

Extreme prematurity per se is not a risk factor for lower PF at school age. However, if complicated by BPD, PF is significantly and sustainably reduced.

Neuroimaging of brain connectivity related to reading outcomes in children born preterm: A critical narrative review

Premature children are at high risk for delays in language and reading, which can lead to poor school achievement. Neuroimaging studies have assessed structural and functional connectivity by diffusion MRI, functional MRI, and magnetoencephalography, in order to better define the "reading network" in children born preterm. Findings point to differences in structural and functional connectivity compared to children born at term. It is not entirely clear whether this discrepancy is due to delayed development or alternative mechanisms for reading, which may have developed to compensate for brain injury in the perinatal period. This narrative review critically appraises the existing literature evaluating the neural basis of reading in preterm children, summarizes the current findings, and suggests future directions in the field.

A method for identifying critical time windows of maternal air pollution exposures associated with low birth weight in offspring using massive geographic data

Associations between maternal exposures to air pollutants and low birth weight (LBW) in offspring varied when different exposure windows were considered. Methods used in previous studies lacked flexibility in delineating exposure windows and did not consider time periods before conception, which may restrict the discoveries of critical exposure windows. This study introduces a novel method to identify critical windows of maternal air pollution exposures associated with LBW in offspring using massive georeferenced data. Through a case-control study based on birth data (94,106 LBW cases and 376,424 controls) and air quality monitoring data (367 chemicals) in Texas during 1996-2008, this study used the average ambient concentration measured by the monitoring site closest to the residence location of a mother during a time window as the maternal exposure to a specific chemical during that exposure window. Binary logistic regression was utilized to estimate air pollutant-LBW associations in different exposure windows. The odds ratios (ORs) were adjusted for child's sex, gestational weeks, maternal age, race/ethnicity, and education. The adjusted ORs were plotted against the exposure window series of different sizes for each chemical, aiming at interactively visualizing and exploring the critical exposure windows across multiple temporal scales. This study identifies ten chemicals and seventeen corresponding critical exposure windows where strong air pollutant-LBW associations are detected. The ten identified chemicals are benzaldehyde, sum of Photochemical Assessment Monitoring Stations (PAMS) target compounds, n-undecane, m-tolualdehyde, organic carbon fraction 2 (OC2), ethylene dibromide, valeraldehyde, propionaldehyde, 4-methyl-1-pentene, and zirconium. Nine critical exposure windows involving six chemicals start more than five months prior to conception, seven windows involving five chemicals commence in the second and/or third trimester of pregnancy, and the remaining one window is located in other time periods. The novel method reveals a number of critical time windows of maternal exposure to ten chemicals that are positively associated with LBW in offspring. These ten chemicals were identified as LBW risk factors for the first time. Additional studies with more data are needed to validate the results in the future.

Cognitive and academic outcomes of children born extremely preterm

Extremely preterm birth is associated with increased risk for a spectrum of neurodevelopmental problems. This review describes the nature of cognitive and academic outcomes of extremely preterm survivors across childhood and adolescence. Evidence across meta-analyses and large prospective birth cohorts indicate that early developmental difficulties in children born extremely preterm do not resolve with age and are not improving over time despite advancements in neonatal care. While extremely preterm birth confers increased risk of widespread cognitive difficulties, considerable heterogeneity in outcomes is evident across individuals. There is a continued need for high-quality longitudinal studies to understand the developmental progression of cognitive and academic skills following extremely preterm birth, and greater focus on understanding contributing factors that may help to explain the individual variability in cognitive and academic outcomes of extremely preterm survivors.

Neuroimaging at Term Equivalent Age: Is There Value for the Preterm Infant? A Narrative Summary

Advances in neuroimaging of the preterm infant have enhanced the ability to detect brain injury. This added information has been a blessing and a curse. Neuroimaging, particularly with magnetic resonance imaging, has provided greater insight into the patterns of injury and specific vulnerabilities. It has also provided a better understanding of the microscopic and functional impacts of subtle and significant injuries. While the ability to detect injury is important and irresistible, the evidence for how these injuries link to specific long-term outcomes is less clear. In addition, the impact on parents can be profound. This narrative summary will review the history and current state of brain imaging, focusing on magnetic resonance imaging in the preterm population and the current state of the evidence for how these patterns relate to long-term outcomes.

Intranasal IL-4 Administration Alleviates Functional Deficits of Periventricular Leukomalacia in Neonatal Mice

Background: Periventricular leukomalacia (PVL) is the major form of brain injury in premature infants. Currently, there are no therapies to treat PVL. Several studies suggested that polarization of microglia, a resident macrophage-like immune cell in the central nervous system, plays a vital role in brain injury and recovery. As an important mediator of immunity, interleukin-4 (IL-4) has critical effects on many immune cells, such as astrocytes and microglia. Increasing evidence shows that IL-4 plays a well-established role in attenuating inflammation in neurological disorders. Additionally, as a noninvasive and highly effective method, intranasal drug administration is gaining increasing attention. Therefore, in our study, we hypothesized that intranasal IL-4 administration is a promising strategy for PVL treatment.

Methods: The therapeutic effects of IL-4 on neuroprotection were evaluated using a Control group, Hypoxia group, and Hypoxia + IL-4 treatment group. The PVL mouse model was established by a severe acute hypoxia (SAH) protocol. Exogenous IL-4 was intranasally administered to investigate its neuroprotective effects. A functional study was used to investigate neurological deficits, immunohistochemical technology and Western blotting were used to detect protein levels, and electron microscopy was used to evaluate myelination.

Results: The results suggested that hypoxia stimulated Iba1⁺ microglial activation, downregulated myelin-related gene (NG2, MAG, and MBP) expression, reduced MBP protein levels, and caused neurological deficits. However, the intranasal administration of exogenous IL-4 partially inhibited Iba1+ microglial activation, improved myelination, and alleviated neurological deficits. The mechanistic study showed that IL-4 improved myelination possibly through the IL-4Ra-mediated polarization of microglia from the M1 phenotype to the M2 phenotype.

Conclusion: In summary, our findings demonstrated that the intranasal administration of exogenous IL-4 improves myelination and attenuates functional deficits in a hypoxia-induced PVL model. Intranasal IL-4 administration may be a promising strategy for PVL treatment, for which further mechanistic studies are urgent.

Healthcare access and adverse family impact among U.S. children ages 0-5 years by prematurity status

BACKGROUND

Many children and their families are affected by premature birth. Yet, little is known about their healthcare access and adverse family impact during early childhood. This study aimed to (1) examine differences in healthcare access and adverse family impact among young children by prematurity status and (2) determine associations of healthcare access with adverse family impact among young children born prematurely.

METHODS

This was a secondary analysis of cross-sectional 2016 and 2017 National Survey of Children's Health data. The sample included 19,482 U.S. children ages 0-5 years including 242 very low birthweight (VLBW) and 2205 low birthweight and/or preterm (LBW/PTB) children. Prematurity status was defined by VLBW (i.e., < 1500 g at birth) and LBW/PTB (i.e., 1500-2499 g at birth and/or born at < 37 weeks with or without LBW). Healthcare access measures were adequate health insurance, access to medical home, and developmental screening receipt. Adverse family impact measures were ≥ $1000 in annual out-of-pocket medical costs, having a parent cut-back or stop work, parental aggravation, maternal health not excellent, and paternal health not excellent. The relative risk of each healthcare access and adverse family impact measure was computed by prematurity status. Propensity weighted models were fit to estimate the average treatment effect of each healthcare access measure on each adverse family impact measure among children born prematurely (i.e., VLBW or LBW/PTB).

RESULTS

Bivariate analysis results showed that VLBW and/or LBW/PTB children generally fared worse than other children in terms of medical home, having a parent cut-back or stop working, parental aggravation, and paternal health. Multivariable analysis results only showed, however, that VLBW children had a significantly higher risk than other children of having a parent cut-back or stop work. Adequate health insurance and medical home were each associated with reduced adjusted relative risk of ≥$1000 in annual out-of-pocket costs, having a parent cut-back or stop work, and parental aggravation among children born prematurely.

CONCLUSIONS

This study's findings demonstrate better healthcare access is associated with reduced adverse family impact among U.S. children ages 0-5 years born prematurely. Population health initiatives should target children born prematurely and their families.

Rewiring the extremely preterm brain: Altered structural connectivity relates to language function

Children born preterm are at increased risk for cognitive impairment, with higher-order functions such as language being especially vulnerable. Previously, we and others have reported increased interhemispheric functional connectivity in children born extremely preterm; the finding appears at odds with literature showing decreased integrity of the corpus callosum, the primary commissural bundle, in preterm children. We address the apparent discrepancy by obtaining advanced measures of structural connectivity in twelve school-aged children born extremely preterm (<28 weeks) and ten term controls. We hypothesize increased extracallosal structural connectivity might support the functional hyperconnectivity we had previously observed. Participants were aged four to six years at time of study and groups did not differ in age, sex, race, ethnicity, or socioeconomic status. Whole-brain and language-network-specific (functionally-constrained) connectometry analyses were performed. At the whole-brain level, preterm children had decreased connectivity in the corpus callosum and increased connectivity in the cerebellum versus controls. Functionally-constrained analyses revealed significantly increased extracallosal connectivity between bilateral temporal regions in preterm children (FDRq <0.05). Connectivity within these extracallosal pathways was positively correlated with performance on standardized language assessments in children born preterm (FDRq <0.001), but unrelated to performance in controls. This is the first study to identify anatomical substrates for increased interhemispheric functional connectivity in children born preterm; increased reliance on an extracallosal pathway may represent a biomarker for resiliency following extremely preterm birth.

The association between maternal interaction and infant cortisol stress reactivity among preterm and full term infants at 4 months adjusted age

The purpose of this study was to assess the association between maternal interactive behavior and infant cortisol stress reactivity in response to the Still Face paradigm (SF) in a cohort of four-month old infants (adjusted age) born preterm (<32 weeks gestation, N = 22) compared with infants born full term (>37 weeks gestation, N = 28). Infant cortisol reactivity was calculated as area under the curve (AUC) from baseline to the third cortisol sample (30 min post-SF) using the trapezoidal rule, while the percent of time mothers spent using a contingent interaction style was measured (0-100%) during episodes 1 (Play; baseline), 3 (Reunion#1), and 5 (Reunion#2) while mother-infant dyads participated in the SF paradigm. We hypothesized that because infants born preterm are at increased risk for dysregulation, they would show, compared to full-term infants, a blunted stress response, involving under-responsiveness. We found blunted cortisol stress reactivity among the preterm infants. We also found that mothers of preterm infants demonstrated less contingent maternal interaction during Renion#1 of the SF; and that contingent maternal interaction at Reunion#2 of the SF was protective against cortisol stress reactivity in response to the SF. However, we did not find that the influence of maternal interaction on cortisol reactivity was moderated by gestational age group (full term vs preterm): the association between contingent maternal interaction and stress reactivity was similar for both gestational groups across episodes. In order to improve self-regulation and longer term social and cognitive developmental outcomes in medically at-risk infants, future research is warranted to determine how these findings relate to infants' stress reactions in naturalistic settings, and the directionality and temporal relationship between cortisol stress responses and maternal interactive behavior.

Glutamate Transport and Preterm Brain Injury

Preterm birth complications are the leading cause of child death worldwide and a top global health priority. Among the survivors, the risk of life-long disabilities is high, including cerebral palsy and impairment of movement, cognition, and behavior. Understanding the molecular mechanisms of preterm brain injuries is at the core of future healthcare improvements. Glutamate excitotoxicity is a key mechanism in preterm brain injury, whereby the accumulation of extracellular glutamate damages the delicate immature oligodendrocytes and neurons, leading to the typical patterns of injury seen in the periventricular white matter. Glutamate excitotoxicity is thought to be induced by an interaction between environmental triggers of injury in the perinatal period, particularly cerebral hypoxia-ischemia and infection/inflammation, and developmental and genetic vulnerabilities. To avoid extracellular build-up of glutamate, the brain relies on rapid uptake by sodium-dependent glutamate transporters. Astrocytic excitatory amino acid transporter 2 (EAAT2) is responsible for up to 95% of glutamate clearance, and several lines of evidence suggest that it is essential for brain functioning. While in the adult EAAT2 is predominantly expressed by astrocytes, EAAT2 is transiently upregulated in the immature oligodendrocytes and selected neuronal populations during mid-late gestation, at the peak time for preterm brain injury. This developmental upregulation may interact with perinatal hypoxia-ischemia and infection/inflammation and contribute to the selective vulnerability of the immature oligodendrocytes and neurons in the preterm brain. Disruption of EAAT2 may involve not only altered expression but also impaired function with reversal of transport direction. Importantly, elevated EAAT2 levels have been found in the reactive astrocytes and macrophages of human infant post-mortem brains with severe white matter injury (cystic periventricular leukomalacia), potentially suggesting an adaptive mechanism against excitotoxicity. Interestingly, EAAT2 is suppressed in animal models of acute hypoxic-ischemic brain injury at term, pointing to an important and complex role in newborn brain injuries. Enhancement of EAAT2 expression and transport function is gathering attention as a potential therapeutic approach for a variety of adult disorders and awaits exploration in the context of the preterm brain injuries.

Resilience in Extremely Preterm/Extremely Low Birth Weight Kindergarten Children

OBJECTIVES

Research on developmental outcomes of preterm birth has traditionally focused on adverse effects. This study investigated the prevalence and correlates of resilience in 146 extremely preterm/extremely low birth weight (EPT/ELBW) children (gestational age &lt;28 weeks and/or birth weight &lt;1000 g) attending kindergarten and 111 term-born normal birth weight (NBW) controls.

METHODS

Adaptive competence (i.e., "resilience" in the EPT/ELBW group) was defined by scores within grade expectations on achievement tests and the absence of clinically elevated parent ratings of child behavior problems. The "adaptive" children who met these criteria were compared to the "maladaptive" children who did not on child and family characteristics. Additional analyses were conducted to assess the conjoint effects of group (ELBW vs. NBW) and family factors on adaptive competence.

RESULTS

A substantial minority of the EPT/ELBW group (45%) were competent compared to a majority of NBW controls (73%), odds ratio (95% confidence interval)=0.26 (0.15, 0.45), p&lt;.001. Adaptive competence was associated with higher cognitive skills, more favorable ratings of behavior and learning not used to define adaptive competence, and more advantaged family environments in both groups, as well as with a lower rate of earlier neurodevelopmental impairment in the EPT/ELBW group. Higher socioeconomic status and more favorable proximal home environments were associated with competence independent of group, and group differences in competence persisted across the next two school years.

CONCLUSIONS

The findings document resilience in kindergarten children with extreme prematurity and highlight the role of environmental factors as potential influences on outcome. (JINS, 2019, 25, 362-374).

The interplay between prematurity, maternal stress and children's intelligence quotient at age 11: A longitudinal study

Very premature children (<33 weeks of gestational age (GA)) experience greater academic difficulties and have lower, though normal-range, intelligence quotients (IQs) versus their full-term peers. These differences are often attributed to GA or familial socio-economic status (SES). However, additional factors are increasingly recognized as likely contributors. Parental stress after a child's premature birth can present as post-traumatic stress disorder (PTSD) symptoms and can in turn reinforce difficulties in parent-child interaction pattern. Following a longitudinal design, we studied the interplay between a premature child's perinatal history and maternal PTSD symptoms on intelligence abilities assessed at 11 years of age. Thirty-three very preterm and 21 full-term mother-children dyads partook in the study. Children's perinatal risk was evaluated at hospital discharge, maternal PTSD symptoms were assessed when the children were 18 months old, and children's IQ was measured at 11 years old. IQ was significantly lower for preterm than full-term children, without reliable influences from perinatal risk scores. However, lower maternal PTSD symptoms predicted higher IQ in preterm children. This preliminary study highlights the importance detecting maternal PTSD symptoms after a preterm birth and suggests interventions should target reducing maternal PTSD symptoms during early childhood to enhance very preterm children's intelligence development.

Aberrant structural and functional connectivity and neurodevelopmental impairment in preterm children

Background

Despite advances in antenatal and neonatal care, preterm birth remains a leading cause of neurological disabilities in children. Infants born prematurely, particularly those delivered at the earliest gestational ages, commonly demonstrate increased rates of impairment across multiple neurodevelopmental domains. Indeed, the current literature establishes that preterm birth is a leading risk factor for cerebral palsy, is associated with executive function deficits, increases risk for impaired receptive and expressive language skills, and is linked with higher rates of co-occurring attention deficit hyperactivity disorder, anxiety, and autism spectrum disorders. These same infants also demonstrate elevated rates of aberrant cerebral structural and functional connectivity, with persistent changes evident across advanced magnetic resonance imaging modalities as early as the neonatal period. Emerging findings from cross-sectional and longitudinal investigations increasingly suggest that aberrant connectivity within key functional networks and white matter tracts may underlie the neurodevelopmental impairments common in this population.

Main body

This review begins by highlighting the elevated rates of neurodevelopmental disorders across domains in this clinical population, describes the patterns of aberrant structural and functional connectivity common in prematurely-born infants and children, and then reviews the increasingly established body of literature delineating the relationship between these brain abnormalities and adverse neurodevelopmental outcomes. We also detail important, typically understudied, clinical, and social variables that may influence these relationships among preterm children, including heritability and psychosocial risks.

Conclusion

Future work in this domain should continue to leverage longitudinal evaluations of preterm infants which include both neuroimaging and detailed serial neurodevelopmental assessments to further characterize relationships between imaging measures and impairment, information necessary for advancing our understanding of modifiable risk factors underlying these disorders and best practices for improving neurodevelopmental trajectories in this high-risk clinical population.

Associations between maternal residential proximity to air emissions from industrial facilities and low birth weight in Texas, USA

BACKGROUND

Most previous studies examining associations between maternal exposures to air pollutants during pregnancy and low birth weight (LBW) in offspring focused on criteria air pollutants (PM_2.5, PM₁₀, O₃, NO₂, SO₂, CO, and Pb). The relationship between non-criteria air pollutants and LBW is understudied and requires greater coverage.

OBJECTIVES

This study investigated associations between maternal residential exposure to industrial air pollutants during pregnancy and LBW in offspring.

METHODS

This study used a case-control study design that included 94,106 term LBW cases and 376,424 controls. It covered 78 air pollutants common to both the Toxics Release Inventory (TRI) and ground air quality monitoring databases in Texas during 1996-2008. A modified version of the Emission Weighted Proximity Model (EWPM), calibrated with ground monitoring data, was used to estimate maternal residential exposure to industrial air pollutants during pregnancy. Binary logistic regression analyses were performed to calculate odds ratios (ORs) reflecting the associations of maternal exposure to industrial air pollutants and LBW in offspring, adjusted for child's sex, gestational weeks, maternal age, education, race/ethnicity, marital status, prenatal care, tobacco use during pregnancy, public health region of maternal residence, and year of birth. In addition, the Bonferroni correction for multiple comparisons was applied to the results of logistic regression analysis.

RESULTS

Relative to the non-exposed reference group, maternal residential exposure to benzene (adjusted odds ratio (aOR) 1.06, 95% confidence interval (CI) 1.04, 1.08), benzo(g,h,i)perylene (aOR 1.04, 95% CI 1.02, 1.07), cumene (aOR 1.05, 95% CI 1.03, 1.07), cyclohexane (aOR 1.04, 95% CI 1.02, 1.07), dichloromethane (aOR 1.04, 95% CI 1.03, 1.07), ethylbenzene (aOR 1.05, 95% CI 1.03, 1.06), ethylene (aOR 1.06, 95% CI 1.03, 1.09), mercury (aOR 1.04, 95% CI 1.02, 1.07), naphthalene (aOR 1.03, 95% CI 1.01, 1.05), n-hexane (aOR 1.06, 95% CI 1.04, 1.08), propylene (aOR 1.06, 95% CI 1.03, 1.10), styrene (aOR 1.06, 95% CI 1.04, 1.08), toluene (aOR 1.05, 95% CI 1.03, 1.07), and zinc (fume or dust) (aOR 1.10, 95% CI 1.06, 1.13) was found to have significantly higher odds of LBW in offspring. When the estimated exposures were categorized into four different groups (zero, low, medium, and high) in the analysis, eleven of the fourteen air pollutants, with the exception of benzo(g,h,i)perylene, ethylene, and propylene, remained as significant risk factors.

CONCLUSIONS

Results indicate that maternal residential proximity to industrial facilities emitting any of the fourteen pollutants identified by this study during pregnancy may be associated with LBW in offspring. With the exception of benzene, ethylbenzene, toluene, and zinc, the rest of the fourteen air pollutants are identified as LBW risk factors for the first time by this study. Further epidemiological, biological, and toxicological studies are suggested to verify the findings from this study.

Industrial air pollution and low birth weight: a case-control study in Texas, USA

Many studies have investigated associations between maternal residential exposures to air pollutants and low birth weight (LBW) in offspring. However, most studies focused on the criteria air pollutants (PM_2.5, PM₁₀, O₃, NO₂, SO₂, CO, and Pb), and only a few studies examined the potential impact of other air pollutants on LBW. This study investigated associations between maternal residential exposure to industrial air emissions of 449 toxics release inventory (TRI) chemicals and LBW in offspring using a case-control study design based on a large dataset consisting of 94,106 LBW cases and 376,424 controls in Texas from 1996 to 2008. Maternal residential exposure to chemicals was estimated using a modified version of the emission-weighted proximity model (EWPM). The model takes into account reported quantities of annual air emission from industrial facilities and the distances between the locations of industrial facilities and maternal residence locations. Binary logistic regression was used to compute odds ratios measuring the association between maternal exposure to different TRI chemicals and LBW in offspring. Odds ratios were adjusted for child's sex, birth year, gestational length, maternal age, education, race/ethnicity, and public health region of maternal residence. Among the ten chemicals selected for a complete analysis, maternal residential exposures to five TRI chemicals were positively associated with LBW in offspring. These five chemicals include acetamide (adjusted odds ratio [aOR] 2.29, 95% confidence interval [CI] 1.24, 4.20), p-phenylenediamine (aOR 1.63, 95% CI 1.18, 2.25), 2,2-dichloro-1,1,1-trifluoroethane (aOR 1.41, 95% CI 1.20, 1.66), tributyltin methacrylate (aOR 1.20, 95% CI 1.06, 1.36), and 1,1,1-trichloroethane (aOR 1.11, 95% CI 1.03, 1.20). These findings suggest that maternal residential proximity to industrial air emissions of some chemicals during pregnancy may be associated with LBW in offspring.

What Are We Measuring as Outcome? Looking Beyond Neurodevelopmental Impairment

Outcomes of neonatal intensive care unit (NICU) graduates have been categorized by rates of neurodevelopmental impairment at 2 years old. Although useful as metrics for research, these early childhood assessments may underestimate or overestimate later functional capabilities. Often overlooked are less severe but more prevalent neurobehavioral dysfunctions seen later in childhood, and chronic health concerns that may impact the child's quality of life (QoL). Comprehensive NICU follow-up should include measures of less severe cognitive/learning delays, physical/mental well-being, and the promotion of resilience in children and families. Studies are needed to identify QoL measures that will optimize children's assessments and outcomes.

Anemia of prematurity and cerebral near-infrared spectroscopy: should transfusion thresholds in preterm infants be revised?

OBJECTIVE

To determine the impact of progressive anemia of prematurity on cerebral regional saturation (C-rSO₂) in preterm infants and identify the hemoglobin threshold below which a critical decrease (>2SD below the mean) in C-rSO₂ occurs.

STUDY DESIGN

In a cohort of infants born ≤30 weeks EGA, weekly C-rSO₂ data were prospectively collected from the second week of life through 36 weeks post-menstrual age (PMA). Clinically obtained hemoglobin values were noted at the time of recording. Recordings were excluded if they were of insufficient duration (<1 h) or if the hemoglobin was not measured within 7 days. Statistical analysis was performed using a linear mixed effects-model and ROC analysis. ROC analysis was used to determine the threshold of anemia, where C-rSO₂ critically decreased >2SD below the mean normative value (<55%) in preterm infants.

RESULTS

In total 253 recordings from 68 infants (mean EGA 26.9 ± 2.1 weeks, BW 1025 ± 287 g, 49% male) were included. Approximately 29 out of 68 infants (43%) were transfused during hospitalization. Mixed-model statistical analysis adjusting for EGA, BW, and PMA revealed a significant association between decreasing hemoglobin and C-rSO₂ (p < 0.01) in transfusion-naive infants but not in transfused infants. In the transfusion naive group, using ROC analysis demonstrated a threshold hemoglobin of 9.5 g/dL (AUC 0.81, p < 0.01) for critical cerebral desaturation in preterm infants.

CONCLUSIONS

In transfusion-naive preterm infants, worsening anemia was associated with a progressive decrease in cerebral saturations. Analysis identified a threshold hemoglobin of 9.5 g/dL below which C-rSO₂ dropped >2SD below the mean.

Maternal Age and Offspring's Educational Attainment

Utilizing data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), the current study examines which maternal age at birth provides offspring with optimal opportunities for higher educational attainment. The results show that maternal age has a curvilinear relationship with offspring's educational attainment, i.e., the offspring of younger and older mothers are distinctly disadvantaged. Maternal ages 31 through 40 are associated with the highest offspring educational attainment, suggesting that women who give birth in their 30s have more favorable characteristics than younger or older mothers. The analysis demonstrates that-with the exception of early teenage childbearing-the association between maternal age and offspring's educational attainment likely reflects selection patterns in fertility timing, rather than direct within-family effects of maternal age on offspring's educational attainment. Thus, the results provide insufficient evidence to conclude that delaying childbearing beyond age 18 directly benefits or harms offspring's educational attainment.

Leisure time physical activity in 9- to 11-year-old children born moderately preterm: a cohort study

BACKGROUND

Physical activity is one of the best documented activities with impacts on health in children and adults. Children born preterm show reduced physical and psychosocial function compared to children born at term. This may influence their level of physical activity. Reports on moderately preterm children's physical activities during childhood are limited. Thus, the aim of this study was to compare the leisure time physical activity at age 9-11 years of moderately preterm children with that of children born at term.

METHODS

Data from 4941 mother-child pairs from the Aarhus Birth Cohort (1989-91) were used. The cohort gathered clinical information, including gestational age at delivery. Information about parental socio-demographic and lifestyle factors was obtained from questionnaires completed during the second trimester of pregnancy. Information about children's physical activities was reported in a 9- to 11-year follow-up questionnaire completed by parents detailing how many times per week their child participated in sports activities outside of school, hours spent per week playing outside, and hours per week engaged in sedentary activities. Data were analysed using multiple logistic regression with the lowest activity group as a reference group.

RESULTS

A total of 158 children (3.2%) were born moderately preterm, i.e., between 32 and 36 completed weeks. Children born moderately preterm participated in sports activities as often as their peers born at term; they also participated in frequent sports activities (≥ 4 times per week) as often as their peers. There were no differences in hours per week spent playing outside or in sedentary activities between the two groups.

CONCLUSIONS

Nine- to 11-year-old moderately preterm children participated in sports activities outside school to a similar extent as their peers and engaged in outdoor activities and sedentary activities for the same duration of time per week as their peers born at term.

Effects of Perinatal Factors on Body Mass Index and Physical Fitness of School-age Children

Objective

To examine the effects of various maternal and neonatal perinatal factors on the child’s body mass index (BMI) and physical fitness at school-age.

Methods

Data from two registries, the SLOfit database (a national surveillance system of children’s motor and physical development) and Slovenian National Perinatal Information System (NPIS) were analysed. Perinatal data for 2,929 children born in 2008 were linked to results of SLOfit testing of these children in 2016. Linear regression analysis was used to assess the potential relationship between several perinatal factors (very preterm birth, birth mass, maternal age, hypertensive disorders of pregnancy, gestational diabetes, parity, plurality, maternal pre-pregnancy BMI, mode of delivery, presentation, Apgar score at 5 minutes, and admission to a neonatal intensive care unit (NICU)) and child’s BMI or child’s physical fitness index (PFI) at the age of eight years. We also included child’s school grade and maternal educational level in the analysis. A p value <0.05 was considered statistically significant.

Results

Children born to mothers with lower pre-pregnancy BMI and higher education had lower BMI and higher PFI (p<0.001) at school-age. Physical fitness was also inversely associated with nulliparity (p<0.001) and NICU admission (p=0.020).

Conclusions

Among all perinatal factors studied, higher maternal education and lower pre-pregnancy BMI seem to be the most significant determinants of child’s BMI and physical fitness at school-age.

Mathematics ability and related skills in preschoolers born very preterm

Children born very preterm (VPT) are at risk for academic, behavioral, and/or emotional problems. Mathematics is a particular weakness and better understanding of the relationship between preterm birth and early mathematics ability is needed, particularly as early as possible to aid in early intervention. Preschoolers born VPT (n = 58) and those born full term (FT; n = 29) were administered a large battery of measures within 6 months of beginning kindergarten. A multiple-mediation model was utilized to characterize the difference in skills underlying mathematics ability between groups. Children born VPT performed significantly worse than FT-born children on a measure of mathematics ability as well as full-scale IQ, verbal skills, visual-motor integration, phonological awareness, phonological working memory, motor skills, and executive functioning. Mathematics was significantly correlated with verbal skills, visual-motor integration, phonological processing, and motor skills across both groups. When entered into the mediation model, verbal skills, visual-motor integration, and phonological awareness were significant mediators of the group differences. This analysis provides insights into the pre-academic skills that are weak in preschoolers born VPT and their relationship to mathematics. It is important to identify children who will have difficulties as early as possible, particularly for VPT children who are at higher risk for academic difficulties. Therefore, this model may be used in evaluating VPT children for emerging difficulties as well as an indicator that if other weaknesses are found, an assessment of mathematics should be conducted.

Special health care needs explains the effect of extremely low birth weight on math but not language achievement

OBJECTIVES

Extremely low birth weight (ELBW; <1kg) adolescents are at risk for special health care needs (SHCN) and poor math achievement compared to normal birth weight (NBW) peers. SHCN are associated with poor academic achievement among NBW children. We hypothesize that SHCN explain the effect of ELBW on math achievement.

METHODS

We compared age 14 Woodcock-Johnson Calculation standard scores between 181 ELBW infants and 115 NBW controls. Persistent SHCN included: 1) prescription medication or equipment use, 2) subspecialty or therapeutic service use, or 3) hospitalization. We used nonlinear marginal effects models to decompose the total effect of ELBW on math into the following 4 components: the effect of ELBW controlling for SHCN, the effect of SHCN controlling for ELBW, effect modification by SHCN, and mediated interaction where SHCN is both causal mediator and effect modifier. Models were adjusted for sociodemographic factors.

RESULTS

ELBW adolescents had lower mean math scores than NBW peers (81.3 vs. 96.4). SHCN were more common among ELBW adolescents (54.1% vs. 27%). The total effect of ELBW on math scores was -15.7 points (95% CI -21.0, -10.5). The effect of birth weight alone was -7.6 points (95% CI -13.7, -1.4); the effect of SHCN alone was negligible. SHCN interaction and mediated interaction effects each accounted for 25% of the total effect.

CONCLUSIONS

Birth weight alone explains only half of the effect of ELBW on math achievement. We found evidence of effect modification and mediation by SHCN. Understanding these explanatory pathways may lead to targeted interventions for improved outcomes.

Magnesium Sulfate Prevents Neurochemical and Long-Term Behavioral Consequences of Neonatal Excitotoxic Lesions: Comparison Between Male and Female Mice

Magnesium sulfate (MgSO4) administration to mothers at risk of preterm delivery is proposed as a neuroprotective strategy against neurological alterations such as cerebral palsy in newborns. However, long-term beneficial or adverse effects of MgSO4 and sex-specific sensitivity remain to be investigated. We conducted behavioral and neurochemical studies of MgSO4 effects in males and females, from the perinatal period to adolescence in a mouse model of cerebral neonatal lesion. The lesion was produced in 5-day-old (P5) pups by ibotenate intracortical injection. MgSO4 (600 mg/kg, i.p.) prior to ibotenate prevented lesion-induced sensorimotor alterations in both sexes at P6 and P7. The lesion increased glutamate level at P10 in the prefrontal cortex, which was prevented by MgSO4 in males. In neonatally lesioned adolescent mice, males exhibited more sequelae than females in motor and cognitive functions. In the perirhinal cortex of adolescent mice, the neonatal lesion induced an increase in vesicular glutamate transporter 1 density in males only, which was negatively correlated with cognitive scores. Long-term sequelae were prevented by neonatal MgSO4 administration. MgSO4 never induced short- or long-term deleterious effect on its own. These results also strongly suggest that sex-specific neuroprotection should be foreseen in preterm infants.

Academic Achievement Deficits and Their Neuropsychological Correlates in Children Born Extremely Preterm

OBJECTIVE

The purpose of this study was to examine the risks associated with learning disabilities (LDs) in a large sample of children born extremely preterm. We predicted higher than expected rates of LD, particularly in math, and children with LD in math, reading, or both would have lower intelligence quotients (IQs) and specific patterns of neuropsychological deficits.

METHODS

We evaluated academic achievement, rates of LD, and their neuropsychological correlates in the Extremely Low Gestational Age Newborns (ELGANs) Study cohort of 10-year-old children born at 23 to 27 weeks gestational age. Primary analyses focused on children without intellectual disability (verbal IQ > 70 and nonverbal IQ > 70; N = 668). Low achievement was defined as a standard score ≤85 on the reading or math measures.

RESULTS

The risk of low math achievement scores (27%) was 1.5 times higher than the risk of low reading achievement scores (17%). Children were classified as having LD based on low achievement criteria in reading only (RD, 6.4% of sample), math only (MD, 16.2%), both reading and math (RD/MD, 8.3%), or no reading or math disabilities (No LD, 69.1%). Although all 3 LD groups had multiple neuropsychological weaknesses compared with the No LD group, the RD and MD groups had different patterns of neuropsychological impairment.

CONCLUSION

These children from the ELGAN cohort had higher than expected rates of LD, particularly in mathematics, even after taking socioeconomic status into consideration. These results indicate specific cognitive weaknesses that differ between extremely preterm children with RD and MD.

White matter injury in the preterm infant: pathology and mechanisms

The human preterm brain is particularly susceptible to cerebral white matter injury (WMI) that disrupts the normal progression of developmental myelination. Advances in the care of preterm infants have resulted in a sustained reduction in the severity of WMI that has shifted from more severe focal necrotic lesions to milder diffuse WMI. Nevertheless, WMI remains a global health problem and the most common cause of chronic neurological morbidity from cerebral palsy and diverse neurobehavioral disabilities. Diffuse WMI involves maturation-dependent vulnerability of the oligodendrocyte (OL) lineage with selective degeneration of late oligodendrocyte progenitors (preOLs) triggered by oxidative stress and other insults. The magnitude and distribution of diffuse WMI are related to both the timing of appearance and regional distribution of susceptible preOLs. Diffuse WMI disrupts the normal progression of OL lineage maturation and myelination through aberrant mechanisms of regeneration and repair. PreOL degeneration is accompanied by early robust proliferation of OL progenitors that regenerate and augment the preOL pool available to generate myelinating OLs. However, newly generated preOLs fail to differentiate and initiate myelination along their normal developmental trajectory despite the presence of numerous intact-appearing axons. Disrupted preOL maturation is accompanied by diffuse gliosis and disturbances in the composition of the extracellular matrix and is mediated in part by inhibitory factors derived from reactive astrocytes. Signaling pathways implicated in disrupted myelination include those mediated by Notch, WNT-beta catenin, and hyaluronan. Hence, there exists a potentially broad but still poorly defined developmental window for interventions to promote white matter repair and myelination and potentially reverses the widespread disturbances in cerebral gray matter growth that accompanies WMI.

Functional neural bases of numerosity judgments in healthy adults born preterm

High rates of mathematics learning disabilities among individuals born preterm (<37weeksGA) have spurred calls for a greater understanding of the nature of these weaknesses and their neural underpinnings. Groups of healthy, high functioning young adults born preterm and full term (n=20) completed a symbolic and non-symbolic magnitude comparison task while undergoing functional MRI scanning. Collectively, participants showed activation in superior and inferior frontal and parietal regions previously linked to numeric processing when comparing non-symbolic magnitude arrays separated by small numeric distances. Simultaneous deactivation of the default mode network also was evident during these trials. Individuals born preterm showed increased signal change relative to their full term peers in right inferior frontal and parietal regions when comparing the non-symbolic magnitude arrays. Elevated signal change during non-symbolic task blocks was associated with poorer performance on a calculation task administered outside of the scanner. These findings indicate that healthy, high-functioning adults born preterm may recruit fronto-parietal networks more extensively when processing non-symbolic magnitudes, suggesting that approximate number system training may be an inroad for early intervention to prevent mathematics difficulties in this population.

Very low birth weight is associated with brain structure abnormalities and cognitive function impairments: A systematic review

Very low birth weight (VLBW) children are at risk of structural brain abnormalities and neurocognitive deficits. Since survival rate of the very low birth weight infants has increased over the past decade, a better understanding of the long-term neurocognitive outcomes is needed. The present systematic review investigated the association between VLBW and cognitive function as well as brain structure. PubMed/Medline, Google Scholar, Scopus and Web of Science databases were searched up from January 2000 to January 2015. The study was restricted to the articles that were about VLBW and its association with cognitive function and brain structure. The initial search yielded 721 articles. There were 44 studies eligible for inclusion after applying the exclusion criteria: 24 follow-up, 14 cohort, and 6 longitudinal studies. Based on this systematic review, we suggest that VLBW is positively related to several cognitive problems and brain structure abnormalities. These findings provide evidence about the importance of early assessment of cognitive development and brain structure to identify at-risk children and provide their specific requirements as early as possible.

MRI for premature neonatal brain injury: a case report

This case report aims to extend analytical thinking and clinical reasoning of clinicians and radiographers when presented with diagnosing premature neonatal brain injuries (PNBI). The report considers the uses and merit of magnetic resonance imaging (MRI) in the primary assessment of PNBI. The traditional technique of cranial ultrasound as the first modality of choice can have several limitations, which includes a lower temporal resolution in its ability to differentiate grey-white matter distribution patterns, lower spatial resolution in its ability to accurately map white matter fibre tracts and distribution patterns which are critical in white matter injury pathological events. In this specific case report, MRI was useful for the assessment of haemorrhagic brain injury post partum.Therefore, should MRI be considered, the primary imaging modality in these cases when the concerns about PNBI is presented? This case study explores the current trends in MRI neonatal brain imaging and advancements being made in this field.

Learning disabilities among extremely preterm children without neurosensory impairment: Comorbidity, neuropsychological profiles and scholastic outcomes

BACKGROUND

Children born extremely preterm are at high risk for intellectual disability, learning disabilities, executive dysfunction and special educational needs, but little is understood about the comorbidity of intellectual and learning disabilities in this population.

AIMS

This study explored comorbidity in intellectual disability (ID) and learning disabilities (LD) in children born extremely preterm (EP; <26⁺⁰weeks' gestation).

SUBJECTS AND STUDY DESIGN

A UK national cohort of 161 EP children and 153 term-born controls without neurosensory impairments was assessed at 11years of age (the EPICure Study).

OUTCOME MEASURES

IQ, mathematics and reading attainment, executive function, visuospatial processing and sensorimotor skills were assessed using standardised tests, and curriculum-based attainment and special educational needs (SEN) using teacher reports.

RESULTS

Overall, 75 (47%) EP children and 7 (4.6%) controls had ID or LD (RR 10.12; 95% CI 4.81, 21.27). Comorbidity in ID/LD was more common among EP children than controls (24% vs. 0%). EP children with comorbid ID/LD had significantly poorer neuropsychological abilities and curriculum-based attainment than EP children with an isolated disability or no disabilities. LD were associated with a 3 times increased risk for SEN. However, EP children with ID alone had poorer neuropsychological abilities and curriculum-based attainment than children with no disabilities, yet there was no increase in SEN provision among this group.

CONCLUSIONS

EP children are at high risk for comorbid intellectual and learning disabilities. Education professionals should be aware of the complex nature of EP children's difficulties and the need for multi-domain assessments to guide intervention.

Executive function in children born preterm: Risk factors and implications for outcome

Executive function (EF) refers to the set of cognitive processes involved in the self-regulation of emotion and goal-directed behavior. These skills and the brain systems that support them develop throughout childhood and are frequently compromised in preterm children, even in those with broadly average global cognitive ability. Risks for deficits in EF in preterm children and attendant problems in learning and psychosocial functioning are higher in those with more extreme prematurity, neonatal complications, and related brain abnormalities. Associations of higher levels of EF with more supportive home and school environments suggest a potential for attenuating these risks, especially with early identification. Further research is needed to understand how deficits in EF evolve in preterm children, refine assessment methods, and develop interventions that either promote the development of EF in this population or help children to compensate for these weaknesses.

IGF-1 in retinopathy of prematurity, a CNS neurovascular disease

The retina is part of the central nervous system and both the retina as well as the brain can suffer from severe damage after very preterm birth. Retinopathy of prematurity is one of the major causes of blindness in these children and brain neuronal impairments including cognitive defects, cerebral palsy and intraventricular hemorrhage (IVH) are also complications of very preterm birth. Insulin-like growth factor 1 (IGF-1) acts to promote proliferation, maturation, growth and survival of neural cells. Low levels of circulating IGF-1 are associated with ROP and defects in the IGF-1 gene are associated with CNS disorders including learning deficits and brain growth restriction. Treatment of preterm infants with recombinant IGF-1 may potentially prevent ROP and CNS disorders. This review compares the role of IGF-1 in ROP and CNS disorders. A recent phase 2 study showed a positive effect of IGF-1 on the severity of IVH but no effect on ROP. A phase 3 trial is planned.

A simple screen performed at school entry can predict academic under-achievement at age seven in children born very preterm

AIM

We aimed to compare the academic outcomes of a cohort of children born very preterm (VPT, <32 weeks of gestation) and children born at term at age 7 years and assess the ability of a pre-academic skill screen at age five to predict later academic impairment in children born VPT at age seven.

METHODS

One hundred ninety-four children born VPT (born with either gestational age <30 weeks or birthweight <1250 g) and 70 controls born at term from a prospective birth cohort were compared on academic outcomes (Wide Range Achievement Test, WRAT4) at age seven using regression analyses. Receiver-operating characteristic curves were used to determine whether pre-academic skills (Kaufman Survey of Early Academic and Language Skills, K-SEALS) at age five predicted academic impairment at age seven in 174 of the VPT cohort.

RESULTS

At the age of 7 years, children born VPT had lower mean word reading (-9.7, 95% CI: -14.7 to -4.6), spelling (-8.3, 95% CI: -13.3 to -3.3) and math computation (-10.9, 95% CI: -15.3 to -6.5) scores (all P-values ≤0.001) compared with controls born at term, even after adjusting for social risk and time since school commencement. In terms of pre-academic screening, the Numbers, Letters and Words subtest of the K-SEALS had adequate sensitivity and specificity (70-80%) for predicting children with academic impairment at age seven.

CONCLUSIONS

Children born VPT underperformed in academic outcomes at age seven compared with controls born at term. A pre-academic screening tool used at school entry can predict children born VPT at risk of academic impairment at age seven who could benefit from targeted early intervention.

Executive Functioning and Learning Skills of Adolescent Children Born at Fewer than 26 Weeks of Gestation

Aims

To assess the cognitive and behavioral aspects of executive functioning (EF) and learning skills in extremely preterm (EPT) children compared with term control children aged 10 to 15 years.

Methods

A total of 132 of 134 (98% of all eligible survivors) EPT children born at the 2 Swedish regional tertiary care centers from 1992 to 1998 (mean age = 12 years, mean birth weight = 718 g, and mean gestational age = 24.4 weeks) and 103 matched term controls were assessed. General intelligence was assessed using the Wechsler Intelligence Scale for Children (WISC-III-R), and cognitive aspects of EF were analyzed using EF-sensitive subscales of the WISC-III-R and Tower test of the Delis-Kaplan Executive Function Scale (D-KEFS). Behaviors related to EF and learning skills were assessed using the Five to Fifteen questionnaire, which is a validated parent and teacher instrument. Academic performance in school was assessed by teachers’ responses on Achenbach’s Teachers Report Form. Analyses performed included multivariate analyses of covariance (ANCOVA and MANCOVA) and logistic regression analyses.

Results

The EPT children displayed significant deficits in cognitive aspects of EF compared with the controls, exhibiting decreases on the order of 0.9 SD to 1.2 SD for tasks of verbal conceptual reasoning, verbal and non-verbal working memory, processing speed and planning ability (P <0.001 for all). After excluding the children with major neurosensory impairment (NSI) or a Full Scale intelligence quotient (FSIQ) of < 70, significant differences were observed on all tests. Compared with controls, parents and teachers of EPT children reported significantly more EF-related behavioral problems. MANCOVA of teacher-reported learning skills in children with FSIQ >70 and without major NSI revealed no interactions, but significant main effects were observed for the behavioral composite executive function score, group status (EPT vs control) and FSIQ, for which all effect sizes were medium to large. The corresponding findings of MANCOVA of the parent-reported learning skills were very similar. According to the teachers’ ratings, the EPT children were less well adjusted to the school environment.

Conclusion

EPT children born in the 1990s who received active perinatal care are at an increased risk of executive dysfunction, even after excluding children with significant neurodevelopmental disabilities. Even mild to moderate executive dysfunctions has a significant impact on learning skills. These findings suggest the need for timely interventions that address specific cognitive vulnerabilities and executive dysfunctions.

Diffusion Tensor Imaging Abnormalities in the Cerebral White Matter Correlate with Sex-Dependent Neurobehavioral Deficits in Adult Mice with Neonatal Ischemia

BACKGROUND

Neonatal white matter injury (NWMI) is the leading cause of cerebral palsy in prematurely born children. In order to develop a test bed for therapeutics, we recently reported a mouse model of NWMI by using a modified Rice-Vannucci model of neonatal ischemia on postnatal day 5 (P5) in CD-1 mice. We have previously shown that these mice illustrate initial neuroinflammation and oligodendroglial differentiation arrest followed by long-term dysmyelination, periventricular astrogliosis and axonal injury, resembling human NWMI. The objective of this study was to determine the sex-dependent long-term effects of neonatal brain injury on neurobehavioral and advanced in vivo neuroimaging indices in this mouse model, and to correlate these variables with histopathology.

METHODS

After right common artery ligation on P5, in vivo T2-weighted imaging and diffusion tensor imaging (DTI) were performed on ligated and control animals at 4 and 8 weeks. Common sets of regions of interest were used to compare fractional anisotropy (FA) values between ischemic and control mice. Behavioral testing (open field, startle response and grip strength) was performed at adult age. Finally, the animals were sacrificed for immunohistochemical (IHC) assessment of major white matter tracts.

RESULTS

DTI revealed significant sex-dependent changes in FA values ipsi- and contralateral to the ligation. Behavioral testing showed decreased reaction to acoustic stimuli in males but not females. Similarly, increased number of rearings and lack of novelty-induced habituation in the open field were encountered only in the male subgroup. Several regional correlations were found between FA values and these behavioral alterations. IHC studies revealed degeneration of mature oligodendrocytes and damage of white matter tracts in ligated animals, as previously reported in this model, and showed regional correlation with in vivo FA values and behavioral alterations.

CONCLUSIONS

Our findings suggest structural sex-dependent long-term abnormalities after neonatal ischemia. These changes lead to behavioral deficits resembling common problems of patients with cerebral palsy.

Neonatal brain microstructure correlates of neurodevelopment and gait in preterm children 18-22 mo of age: an MRI and DTI study

BACKGROUND

Near-term brain structure was examined in preterm infants in relation to neurodevelopment. We hypothesized that near-term macrostructural brain abnormalities identified using conventional magnetic resonance imaging (MRI), and white matter (WM) microstructure detected using diffusion tensor imaging (DTI), would correlate with lower cognitive and motor development and slower, less-stable gait at 18-22 mo of age.

METHODS

One hundred and two very-low-birth-weight preterm infants (≤1,500 g birth weight; ≤32 wk gestational age) were recruited prior to routine near-term brain MRI at 36.6 ± 1.8 wk postmenstrual age. Cerebellar and WM macrostructure was assessed on conventional structural MRI. DTI was obtained in 66 out of 102 and WM microstructure was assessed using fractional anisotropy and mean diffusivity (MD) in six subcortical brain regions defined by DiffeoMap neonatal atlas. Neurodevelopment was assessed with Bayley-Scales-of-Infant-Toddler-Development, 3rd-Edition (BSID-III); gait was assessed using an instrumented mat.

RESULTS

Neonates with cerebellar abnormalities identified using MRI demonstrated lower mean BSID-III cognitive composite scores (89.0 ± 10.1 vs. 97.8 ± 12.4; P = 0.002) at 18-22 mo. Neonates with higher DTI-derived left posterior limb of internal capsule (PLIC) MD demonstrated lower cognitive and motor composite scores (r = -0.368; P = 0.004; r = -0.354; P = 0.006) at 18-22 mo; neonates with higher genu MD demonstrated slower gait velocity (r = -0.374; P = 0.007). Multivariate linear regression significantly predicted cognitive (adjusted r(2) = 0.247; P = 0.002) and motor score (adjusted r(2) = 0.131; P = 0.017).

CONCLUSION

Near-term cerebellar macrostructure and PLIC and genu microstructure were predictive of early neurodevelopment and gait.

The Neurological Outcome of Isolated PVL and Severe IVH in Preterm Infants: Is It Fair to Compare?

OBJECTIVE

We compared the neurological outcome of isolated periventricular leukomalacia and severe intraventricular hemorrhage in a cohort of very low birth weight infants born and managed at single tertiary-care center in Saudi Arabia.

METHODS

We undertook a descriptive retrospective chart review of the neurological status of very low birth weight infants who were born and managed over a 5-year period at King Abdulaziz Medical City, Riyadh. The neurological outcome of neonates with isolated periventricular leukomalacia and severe intraventricular hemorrhage (grades III and IV) was studied and compared in relation to developmental delay and cerebral palsy.

RESULTS

A total of 20 patients with isolated periventricular leukomalacia and 26 with severe intraventricular hemorrhage (grades III and IV) were identified for this study. Of 20 patients with isolated periventricular leukomalacia, 9 (45%) had good developmental outcome and 11 (55%) had bad developmental outcome. Of 26 patients of severe intraventricular hemorrhage, 14 (54%) had good developmental outcome and 12 (46%) had bad developmental outcome (P = 0.55). Significant motor neurological deficit affecting function is distributed as follows: 11/20 (55%) in the isolated periventricular leukomalacia group and 7/26 (27%) in the severe intraventricular hemorrhage group (P = 0.05). Cerebral palsy was diplegic in 7/11 (64%) and quadriplegic in 4/11 (36%) in the isolated periventricular leukomalacia group, and hemiplegic 3/7 (43%), diplegic in 1/7 (14%), and quadriplegic in 3/7 (43%) in the severe intraventricular hemorrhage group (P = 0.03). Distribution of the neurological outcome according to periventricular leukomalacia grade was as follows: for periventricular leukomalacia grade I (n = 8), 6/8 (75%) had good neurological outcome and 2/8 (25%) had bad neurological outcome. In periventricular leukomalacia grade II (n = 4), good neurological outcome was seen in three patients (75%) and bad neurological outcome was seen in one patient (25%). All patients (n = 8) with periventricular leukomalacia grade III had bad outcome (P < 0.01).

CONCLUSION

About half of patients with isolated periventricular leukomalacia and severe intraventricular hemorrhage had a poor developmental outcome. However, the severity of cerebral palsy was greater in the isolated periventricular leukomalacia patients and correlates highly with periventricular leukomalacia grade. Symmetrical diplegic cerebral palsy is the most common motor deficit associated with isolated periventricular leukomalacia, whereas asymmetrical hemiplegic cerebral palsy is seen exclusively with severe intraventricular hemorrhage.

The Effects of Low Birth Weight on School Performance and Behavioral Outcomes of Elementary School Children in Oman

OBJECTIVES

Our study aimed to examine the effects of low birth weight (LBW) on the school performance and behavior of elementary school children in Oman. .

METHODS

Data were gathered through a cross-sectional survey of nine elementary schools from the Muscat and A'Dhahirah regions. The study utilized a unique database created by linking information from the children's health cards and current academic and behavioral performance records. Information on children's performance in various areas such as language, mathematics, science, information technology, sports, and behavior were obtained from the school registers. Birth weight (BW) and selected sociodemographic data were obtained from the copy of their health cards kept by each school. A total of 542 elementary school children aged 7-11 years, who had completed grades 2-4, were surveyed.  .

RESULTS

Data from the school register revealed a very high rate (17.7%) of LBW and, overall, 12% of the children exhibited below average performance on selected outcome measures. The below average school performance varied from 5-17% across the six selected areas of school performance. The highest rate of below average performance was observed in science (17%), followed by arithmetic and language (16% each). BW showed significant differential effects on school performance and behavioral outcomes, which remained significant after controlling for the effect of potential confounders. It was found that LBW children were 2-6 times more likely to have poorer school performance in all areas than their normal BW peers. .

CONCLUSION

Early intervention programs or special care for LBW children in school could be an effective means of improving educational outcomes and the behavior of these children. Attempts should be made to reduce or prevent poor pregnancy outcomes, which, in turn, would reduce the cost of the health, education, and social services systems.

Neonatal MRI is associated with future cognition and academic achievement in preterm children

School-age children born preterm are particularly at risk for low mathematical achievement, associated with reduced working memory and number skills. Early identification of preterm children at risk for future impairments using brain markers might assist in referral for early intervention. This study aimed to examine the use of neonatal magnetic resonance imaging measures derived from automated methods (Jacobian maps from deformation-based morphometry; fractional anisotropy maps from diffusion tensor images) to predict skills important for mathematical achievement (working memory, early mathematical skills) at 5 and 7 years in a cohort of preterm children using both univariable (general linear model) and multivariable models (support vector regression). Participants were preterm children born <30 weeks' gestational age and healthy control children born ≥37 weeks' gestational age at the Royal Women's Hospital in Melbourne, Australia between July 2001 and December 2003 and recruited into a prospective longitudinal cohort study. At term-equivalent age ( ±2 weeks) 224 preterm and 46 control infants were recruited for magnetic resonance imaging. Working memory and early mathematics skills were assessed at 5 years (n = 195 preterm; n = 40 controls) and 7 years (n = 197 preterm; n = 43 controls). In the preterm group, results identified localized regions around the insula and putamen in the neonatal Jacobian map that were positively associated with early mathematics at 5 and 7 years (both P < 0.05), even after covarying for important perinatal clinical factors using general linear model but not support vector regression. The neonatal Jacobian map showed the same trend for association with working memory at 7 years (models ranging from P = 0.07 to P = 0.05). Neonatal fractional anisotropy was positively associated with working memory and early mathematics at 5 years (both P < 0.001) even after covarying for clinical factors using support vector regression but not general linear model. These significant relationships were not observed in the control group. In summary, we identified, in the preterm brain, regions around the insula and putamen using neonatal deformation-based morphometry, and brain microstructural organization using neonatal diffusion tensor imaging, associated with skills important for childhood mathematical achievement. Results contribute to the growing evidence for the clinical utility of neonatal magnetic resonance imaging for early identification of preterm infants at risk for childhood cognitive and academic impairment.

Congenital cardiac anomalies and white matter injury

Cardiac abnormalities are the most common birth defects. Derangement of circulatory flow affects many vital organs; without proper supply of oxygenated blood, the brain is particularly vulnerable. Although surgical interventions have greatly reduced mortality rates, patients often suffer an array of neurological deficits throughout life. Neuroimaging provides a macroscopic assessment of brain injury and has shown that white matter (WM) is at risk. Oligodendrocytes and myelinated axons have been identified as major targets of WM injury, but still little is known about how congenital heart anomalies affect the brain at the cellular level. Further integration of animal model studies and clinical research will define novel therapeutic targets and new standards of care to prevent developmental delay associated with cardiac abnormalities.

Test of visuospatial construction: Validity evidence in extremely low birth weight and late preterm children at early school age

The Test of Visuospatial Construction (TVSC), a measure of visuoconstruction that does not rely on upper extremity motor response or written production, was administered to extremely low birth weight (ELBW), late preterm (LPT), and term participants at preschool (n = 355) and kindergarten (n = 265) ages. TVSC showed statistically significant weak-to-moderate positive correlations (age 3: r = .118-.303; age 6: r = .138-.348) with Developmental VMI, Differential Ability Scales-II Copying, Matrices, and Pattern Construction subtests, Baron-Hopkins Board Test, and the Purdue Pegboard. One-way ANOVA indicated ELBW performed worse than Term (p = .044) on visuospatial construction at age 3 with a small-to-medium effect size (d = -0.43). No other statistically significant differences were found at age 3 on the TVSC (ELBW/LPT: p = .608, d = -0.17; LPT/Term: p = .116, d = -0.31). At age 6, ELBW participants performed worse than LPT participants (p = .027) and Term participants (p = .012); LPT participants did not differ from Term participants. Small effect sizes at age 3 (ELBW < LPT, d = -0.17; ELBW < Term, d = -0.43) were notably larger at age 6 (ELBW < LPT, d = -0.42; ELBW < Term, d = -0.53). Important practical differences showing LPT participants performed below Term participants (d = -0.31) at age 3 were no longer evident at age 6 (d = -0.097). These findings provide preliminary evidence of TVSC validity supporting its use to detect neuropsychological impairment and to recommend appropriate interventions in young preterm children.

Reading abilities in school-aged preterm children: a review and meta-analysis

AIM

Children born preterm (at ≤32wks) are at risk of developing deficits in reading ability. This meta-analysis aims to determine whether or not school-aged preterm children perform worse than those born at term in single-word reading (decoding) and reading comprehension.

METHOD

Electronic databases were searched for studies published between 2000 and 2013, which assessed decoding or reading comprehension performance in English-speaking preterm and term-born children aged between 6 years and 13 years, and born after 1990. Standardized mean differences in decoding and reading comprehension scores were calculated.

RESULTS

Nine studies were suitable for analysis of decoding, and five for analysis of reading comprehension. Random-effects meta-analyses showed that children born preterm had significantly lower scores (reported as Cohen's d values [d] with 95% confidence intervals [CIs]) than those born at term for decoding (d=-0.42, 95% CI -0.57 to -0.27, p<0.001) and reading comprehension (d=-0.57, 95% CI -0.68 to -0.46, p<0.001). Meta-regressions showed that lower gestational age was associated with larger differences in decoding (Q[1]=5.92, p=0.02) and reading comprehension (Q[1]=4.69, p=0.03) between preterm and term groups. Differences between groups increased with age for reading comprehension (Q[1]=5.10, p=0.02) and, although not significant, there was also a trend for increased group differences for decoding (Q[1]=3.44, p=0.06).

INTERPRETATION

Preterm children perform worse than peers born at term on decoding and reading comprehension. These findings suggest that preterm children should receive more ongoing monitoring for reading difficulties throughout their education.