Neonatal white matter abnormalities predict global executive function impairment in children born very preterm

Interventions to improve executive functions in children aged 3 years and under: A systematic review

BACKGROUND

Early executive functioning (EF) skills are foundational capabilities that predict school readiness, academic development and psychiatric risk. Early interventions enhancing these capabilities could have critical import in improving outcomes. However, to develop interventions, it is necessary to identify specific EF skills that will vary with child age. Thus, we aimed to examine the characteristics and efficacy of interventions targeting EF in infancy and early childhood up to age 3.

METHODS

A comprehensive search of PubMed, Embase, CINAHL and APA PsycINFO databases was performed for studies published before December 2022. Randomized and non-randomized studies of interventions designed to improve at least one EF skill in children ≤3 years were included. EF skills included attentional control, inhibition/self-regulation, activity initiation, working memory, cognitive flexibility, planning ability, problem-solving and performance monitoring. We independently extracted data, used the revised Cochrane Risk-of-Bias tool to assess the quality of the evidence and conducted Synthesis Without Meta-analysis (SWiM). The overall quality of the evidence and the strength of recommendations was determined using elements of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Thirty-five studies met inclusion criteria (original n = 7467). Studies were highly variable in the EF skill targeted, target subject (i.e., child, parent and teacher), nature and dosage of the intervention, and timing of outcome assessment. Most interventions focused on improving impulse control and self-regulation. The overall quality of evidence was low to moderate with a high risk of bias, though six studies had low risk of bias but yielded mixed findings of efficacy.

CONCLUSIONS

The relatively small number of early EF intervention studies uses such variable methods that there is currently no converging evidence of efficacy to recommend a specific intervention. Thus, findings support the need for a more systematic, targeted approach to the design and implementation of early EF interventions for target populations.

Socioeconomic disadvantage and parental mood/affective problems links negative parenting and executive dysfunction in children born very preterm

Poverty increases the risk of poorer executive function (EF) in children born full-term (FT). Stressors associated with poverty, including variability in parenting behavior, may explain links between poverty and poorer EF, but this remains unclear for children born very preterm (VPT). We examine socioeconomic and parental psychosocial adversity on parenting behavior, and whether these factors independently or jointly influence EF in children born VPT. At age five years, 154 children (VPT = 88, FT = 66) completed parent-child interaction and EF tasks. Parental sensitivity, intrusiveness, cognitive stimulation, and positive and negative regard were coded with the Parent-Child Interaction Rating Scale. Socioeconomic adversity spanned maternal demographic stressors, Income-to-Needs ratio, and Area Deprivation Index. Parents completed measures of depression, anxiety, inattention/hyperactivity, parenting stress, and social-communication interaction (SCI) problems. Parental SCI problems were associated with parenting behavior in parents of children born VPT, whereas socioeconomic adversity was significant in parents of FT children. Negative parenting behaviors, but not positive parenting behaviors, were related to child EF. This association was explained by parental depression/anxiety symptoms and socioeconomic adversity. Results persisted after adjustment for parent and child IQ. Findings may inform research on dyadic interventions that embed treatment for parental mood/affective symptoms and SCI problems to improve childhood EF.

Interventions for Executive Function in High-Risk Infants and Toddlers

This review summarizes the current state of evidence regarding interventions for executive function in high-risk infants and toddlers. Currently, there is a paucity of data in this area, with the interventions that have been studied highly variable in their content, dosage, target, and results. Self-regulation is the executive function construct targeted the most, with mixed results. The few studies that report later child outcomes in prekindergarten/school-aged children are encouraging, overall indicating improved cognition and behavior in the children of parents who received a parenting style intervention.

Fronto-Parietal and White Matter Haemodynamics Predict Cognitive Outcome in Children with Moyamoya Independent of Stroke

Moyamoya disease is a major arteriopathy characterised by progressive steno-occlusion of the arteries of the circle of Willis. Studies in adults with moyamoya suggest an association between abnormal fronto-parietal and white matter regional haemodynamics and cognitive impairments, even in the absence of focal infarction. However, these associations have not been investigated in children with moyamoya. We examined the relationship between regional haemodynamics and ratings of intellectual ability and executive function, using hypercapnic challenge blood oxygen level-dependent magnetic resonance imaging of cerebrovascular reactivity in a consecutive cohort of children with confirmed moyamoya. Thirty children were included in the final analysis (mean age: 12.55 ± 3.03 years, 17 females, 15 idiopathic moyamoya and 15 syndromic moyamoya). Frontal haemodynamics were abnormal in all regardless of stroke history and comorbidity, but occipital lobe haemodynamics were also abnormal in children with syndromic moyamoya. Executive function deficits were noted in both idiopathic and syndromic moyamoya, whereas intellectual ability was impaired in syndromic moyamoya, even in the absence of stroke. Analysis of the relative effect of regional abnormal haemodynamics on cognitive outcomes demonstrated that executive dysfunction was predominantly explained by right parietal and white matter haemodynamics independent of stroke and comorbidity, while posterior circulation haemodynamics predicted intellectual ability. These results suggest that parietal and posterior haemodynamics play a compensatory role in overcoming frontal vulnerability and cognitive impairment.

Routine Use of Cerebral Magnetic Resonance Imaging in Infants Born Extremely Preterm

OBJECTIVE

To describe cerebral abnormalities and their risk factors in a contemporary cohort of infants born extremely premature after the introduction of routine cerebral magnetic resonance imaging (cMRI) at term-equivalent age.

STUDY DESIGN

All cMRI examinations performed during November 2017 and November 2020, based on a standardized neonatal cMRI protocol, were included into analysis. Pathologies were retrospectively classified into 3 categories: intraventricular hemorrhage (IVH), white matter disease, and cerebellar injuries.

RESULTS

A total of 198 cMRI examinations were available for analyses; 93 (47%) showed abnormalities, most frequently IVH (n = 65, 33%), followed by cerebellar injuries (n = 41, 21%), and white matter disease (n = 28, 14%). Severe abnormalities were found in 18% of patients (n = 36). Significant clinical risk factors for abnormalities on cMRI were lower Apgar scores, lower umbilical artery and first neonatal pH, asphyxia, blood culture-proven sepsis (especially late-onset), and prolonged need of respiratory support and supplemental oxygen.

CONCLUSIONS

After routine cMRI, without preconfirmed pathology by cranial ultrasonography, low-grade IVH, noncystic white matter disease, and cerebellar injuries were the most frequently found abnormalities. The clinical value and long-term benefit of the detection of these low-grade pathologies have yet to be confirmed.

Prematurity, maternal emotional distress, and infant social responsiveness among Arab-Bedouin families: The role of social support as a resilience factor

This study investigated predictors of early infant social development and the role of social support as a resilience factor among Arab-Bedouin families. We propose a mediation model in which social support will be related to maternal postpartum emotional distress (PPED), which in turn will be related to infant social responsiveness. One hundred five Arab-Bedouin mothers (age range = 17-44 years) and their preterm (n = 48) and full-term (n = 57) infants were recruited shortly after birth and were followed up at age 12 months. Findings demonstrate that, among the preterm group, higher levels of social support predicted lower levels of maternal PPED, and this, in turn, predicted higher levels of infant social responsiveness.

The central executive network and executive function in healthy and persons with schizophrenia groups: a meta-analysis of structural and functional MRI

This meta-analysis evaluated the extent to which executive function can be understood with structural and functional magnetic resonance imaging. Studies included structural in schizophrenia (k = 8; n = 241) and healthy controls (k = 12; n = 1660), and functional in schizophrenia (k = 4; n = 104) and healthy controls (k = 12; n = 712). Results revealed a positive association in the brain behavior relationship when pooled across schizophrenia and control samples for structural (pr = 0.27) and functional (pr = 0.29) modalities. Subgroup analyses revealed no significant difference for functional neuroimaging (pr = .43, 95%CI = -.08-.77, p = .088) but with structural neuroimaging (pr = .37, 95%CI = -.08-.69, p = .015) the association to executive functions is lower in the control group. Subgroup analyses also revealed no significant differences in the strength of the brain-behavior relationship in the schizophrenia group (pr = .59, 95%CI = .58-.61, p = .881) or the control group (pr = 0.19, 95%CI = 0.18-0.19, p = 0.920), suggesting concordance.

Predictive value of brain MRI at term-equivalent age in extremely preterm children on neurodevelopmental outcome at school-age

This study's objective was to correlate the abnormalities in brain MRIs performed at corrected-term age for minor or moderate neurocognitive disorders in children school-age born extremely premature (EPT) and without serious sequelae such as autism, cerebral palsy, mental impairment. Data were issued from a cross-sectional multicenter study (GP-Qol study, number NCT01675726). Clinical examination and psychometric assessments were performed when the children were between 7 and 10 years old during a day-long evaluation. Term-equivalent age brain MRIs on EPT were analyzed with a standardized scoring system. There were 114 children included in the study. The mean age at the time of evaluation, was 8.47 years old (± 0.70). 59% of children with at least one cognitive impairment and 53% who had a dysexecutive disorder. Only ten EPT (8.7%) presented moderate to severe white and grey matter abnormalities. These moderate to severe grey matter abnormalities were associated with at least two abnormal executive functions [OR 3.08 (95% CI 1.04-8.79), p = 0.04] and language delay [OR 3.25 (95% CI 1.03-9.80), p = 0.04]. These results remained significant in the multivariate analysis. Moderate to severe ventricular dilatation abnormalities (15%, n = 17) were associated with ideomotor dyspraxia [OR 7.49 (95% CI 1.48-35.95), p = 0.02] and remained significant in multivariate analysis [OR 11.2 (95% CI 1.45-131.4), p = 0.02]. Biparietal corrected diameters were moderate abnormal in 20% of cases (n = 23) and were associated to visuo spatial integration delay [OR 4.13 (95% CI 1.23-13.63), p = 0.02]. Cerebral MRI at term-equivalent age with scoring system analysis can provide information on long-term neuropsychological outcomes at school-age in EPTs children having no severe disability.

Neurodevelopmental outcomes in preterm infants with retinopathy of prematurity

Over the past decade there has been a paradigm shift in the treatment of retinopathy of prematurity (ROP) with the introduction of antivascular endothelial growth factor (anti-VEGF) treatments. Anti-VEGF agents have the advantages of being easier to administer, requiring less anesthesia, having the potential for improved peripheral vision, and producing less refractive error than laser treatment. On the other hand, it is known that intravitreal administration of anti-VEGF agents lowers VEGF levels in the blood and raises the theoretical concern of intraocular anti-VEGF causing deleterious effects in other organ systems, including the brain. As a result, there has been increased attention recently on neurodevelopmental outcomes in infants treated with anti-VEGF agents. These studies should be put into context with what is known about systemic comorbidities, socioeconomic influences, and the effects of extreme prematurity itself on neurodevelopmental outcomes. We summarize what is known about neurodevelopmental outcomes in extremely preterm infants with ROP, discuss the implications for determining the neurodevelopmental status using neurodevelopmental testing as well as other indicators, and review the existing literature relating to neurodevelopmental outcomes in babies treated for ROP.

Heterogeneity of the attentional system's efficiency among very prematurely born pre-schoolers

Very preterm birth increases the risk of ADHD as well as other neurodevelopmental disorders. Deficits within the attentional system were previously signaled in preterm children; however, studies lacked in consideration of an intragroup differentiation. Thus, this study aimed to verify whether deficits in the attentional mechanisms are inter-individually differentiated among very prematurely born children and if so, which biomedical and non-biomedical factors are associated with the profile of deficits within the attentional system. We tested the efficiency of attentional processes among 5-year-old children with the Attention Network Task - Child Version. The results have indicated that 26% of very preterm children presented with the suboptimal functioning of the attentional system (more than 1 SD below mean score of full-term children in attentional alerting and orienting), whereas 74% were characterized by the normal efficiency of attention. The profile of attentional deficits observed among very preterm preschoolers was associated with significantly lower birth weight and decreased family living standard. Very prematurely born children are thus a relatively heterogeneous group in terms of the efficiency of attentional system and deficits apply to only some of those children. Early developmental support aimed at enhancing attentional functioning should be addressed to children with lower birth weight in the first place.

Neonatal brain abnormalities and brain volumes associated with goal setting outcomes in very preterm 13-year-olds

Executive dysfunction including impaired goal setting (i.e., planning, organization skills, strategic reasoning) is documented in children born very preterm (VP; <30 weeks/<1250 g), however the neurological basis for this impairment is unknown. This study sought to examine the relationship between brain abnormalities and brain volumes on neonatal magnetic resonance imaging (MRI) and goal setting abilities of VP 13-year-olds. Participants were 159 children born VP in a prospective longitudinal study. Qualitative brain abnormality scores and quantitative brain volumes were derived from neonatal MRI brain scans (40 weeks' gestational age ± 2 weeks). Goal setting at 13 years was assessed using the Delis-Kaplan Executive Function Systems Tower Test, the Rey Complex Figure, and the Behavioural Assessment of the Dysexecutive System for Children Zoo Map and Six Part Test. A composite score was generated denoting overall performance on these goal setting measures. Separate regression models examined the association of neonatal brain abnormality scores and brain volumes with goal setting performance. There was evidence that higher neonatal white matter, deep grey matter and cerebellum abnormality scores were associated with poorer goal setting scores at 13 years. There was also evidence of positive associations between total brain volume, cerebellum, thalamic and cortical grey matter volumes and goal setting performance. Evidence for the associations largely persisted after controlling for potential confounders. Neonatal brain abnormality and brain volumes are associated with goal setting outcome in VP 13-year-olds. Used in conjunction with other clinical indicators, neonatal MRI may help to identify VP children at risk for later executive dysfunction.

Maternal interactive beliefs and style as predictors of language development in preterm and full term children

Previous research has shown that the quality of mother-child interactions between pre-term children and their mothers tends to be poorer than that of full-term children and their mothers (Forcada-Guex, Pierrehumbert, Borghini, Moessinger & Muller-Nix, 2006). Mothers of pre-term children are less responsive and more intrusive in interactions with their children than mothers of full-term children (Forcada-Guex et al., 2006; Ionio, Lista, Mascheroni, Olivari, Confalonieri, Mastrangelo, Brazzoduro, Balestriero, Banfi, Bonanomi, Bova, Castoldi, Colombo, Introvini & Scelsa, 2017; Laing, McMahon, Ungerer, Taylor, Badawi & Spence, 2010). The current research explored differences between mothers of pre-term and full-term children in terms of interactive beliefs and style, and the potential for language development to be differentially predicted by maternal interactive beliefs and styles in pre-term versus full-term children. Independent t-tests were conducted to compare pre-term and full-term groups in relation to the measures of maternal interactive beliefs and styles. A series of multiple regression analyses were then performed separately for each group to examine the shared and unique contributions of maternal interactive beliefs and styles on full-term versus pre-term children's language development. The results showed that mothers of pre-term children were more intrusive-directive than mothers of full-term children; in contrast, mothers of full-term children were more responsive and supportive-directive in interactions with their children. Moreover, predictors of language development were different in full-term versus pre-term children; in full-term children, maternal supportive beliefs and responsiveness were significant predictors of language development evaluated by both the Bayley Scales of Infant and Toddler Development and the MacArthur Communicative Development Inventory; in the pre-term group, maternal supportive and directive beliefs, as well as supportive and intrusive directiveness, were significant predictors, with the latter being negatively associated with language development indicators. This research can shed light on how to prevent language delay in children and improve mother-child interactions that contribute to language development, which may in turn improve language development in vulnerable children, children born pre-term in particular.

Mental development is associated with cortical connectivity of the ventral and nonspecific thalamus of preterm newborns

INTRODUCTION

The thalamus is a key hub for regulating cortical connectivity. Dysmaturation of thalamocortical networks that accompany white matter injury has been hypothesized as neuroanatomical correlate of late life neurocognitive impairment following preterm birth. Our objective was to find a link between thalamocortical connectivity measures at term equivalent age and two-year neurodevelopmental outcome in preterm infants.

METHODS

Diffusion tensor MRI data of 58 preterm infants (postmenstrual age at birth, mean (SD), 29.71 (1.47) weeks) were used in the study. We utilized probabilistic diffusion tractography to trace connections between the cortex and thalami. Possible associations between connectivity strength, the length of the probabilistic fiber pathways, and developmental scores (Bayley Scales of Infant Development, Second Edition) were analyzed using multivariate linear regression models.

RESULTS

We found strong correlation between mental developmental index and two complementary measures of thalamocortical networks: Connectivity strength projected to a cortical skeleton and pathway length emerging from thalamic voxels (partial correlation, R = .552 and R = .535, respectively, threshold-free cluster enhancement, corrected p-value < .05), while psychomotor development was not associated with thalamocortical connectivity. Post hoc stepwise linear regression analysis revealed that parental socioeconomic scale, postmenstrual age, and the duration of mechanical ventilation at the intensive care unit contribute to the variability of outcome.

CONCLUSIONS

Our findings independently validated previous observations in preterm infants, providing additional evidence injury or dysmaturation of tracts emerging from ventral-specific and various nonspecific thalamus projecting to late-maturing cortical regions are predictive of mental, but not psychomotor developmental outcomes.

Cardiovascular Risk Markers and Cognitive Performance in Children

Markers of cardiovascular risk and cognitive performance were assessed in 347 children. In contrast with body mass index and blood pressure, only retinal microcirculation explained a unique proportion of variance in inhibitory control and information processing, when dependencies between markers of cardiovascular risk were accounted for.

Impact of prematurity on neurodevelopment

The consequences of prematurity on brain functional development are numerous and diverse, and impact all brain functions at different levels. Prematurity occurs between 22 and 36 weeks of gestation. This period is marked by extreme dynamics in the physiologic maturation, structural, and functional processes. These different processes appear sequentially or simultaneously. They are dependent on genetic and/or environmental factors. Disturbance of these processes or of the fine-tuning between them, when caring for premature children, is likely to induce disturbances in the structural and functional development of the immature neural networks. These will appear as impairments in learning skills progress and are likely to have a lasting impact on the development of children born prematurely. The level of severity depends on the initial alteration, whether structural or functional. In this chapter, after having briefly reviewed the neurodevelopmental, structural, and functional processes, we describe, in a nonexhaustive manner, the impact of prematurity on the different brain, motor, sensory, and cognitive functions.

Neurocognitive and social-communicative function of children born very preterm at 10 years of age: Associations with microorganisms recovered from the placenta parenchyma

OBJECTIVE

Infection of the placenta has been associated with preterm birth as well as neurocognitive impairment. This study aimed to determine whether specific bacterial species in the placenta of extremely preterm pregnancies are associated with neurological deficits later in life.

STUDY DESIGN

Using data from 807 children in the ELGAN study the risks of a low score on six neurological assessments in relation to 15 different microbes were quantified with odds ratios.

RESULTS

The presence of certain microbial species in the placenta was associated with lower scores on numerical and oral language assessments. Lactobacillus sp. was associated with decreased risk of a low oral language score and a composite measure of IQ and executive function.

CONCLUSION

Placental microorganisms were associated with neurocognitive, but not social-communicative, outcomes at age 10. In contrast, the presence of the anti-inflammatory Lactobacillus sp. in the placenta was associated with a lower risk of impaired neurocognitive functions.

Association Between Prematurity and Diagnosis of Neurodevelopment Disorder: A Case-Control Study

The aim of this study is to investigate the association between prematurity and diagnosis of neurodevelopmental disorders (ND) (attention deficit/hyperactivity disorder [ADHD] or autism spectrum disorder [ASD]) in Brazilian children and adolescents. Case-control study based on medical records data from a specialized outpatient clinic. Prematurity was defined as gestational age less than 37 weeks. Prematurity was independently associated with diagnosis of a ND (adjusted odds ratio [AOR] 3.46, 95% CI 1.15 - 7.92), as well as with ADHD and ASD diagnosis after a multiple logistic regression analysis. These findings from Brazilian patients are related to what is found in the literature worldwide. Efforts to modify risk factors, such as prematurity, may impact incidence reduction of both ADHD and ASD.

Worse global intellectual and worse neuropsychological functioning in preterm-born children at preschool age: a meta-analysis

AIM

Preterm births (<32 weeks of gestational age) are associated with cognitive problems that are difficult to diagnose in infancy but potentially detectable at preschool age. This review aimed to evaluate the extent to which total intelligence quotient (IQ) and neuropsychological functions at ages three to five years differ between children born at <32 weeks gestational age or < 1500 g birth weight and children born at term. The secondary aim was to determine whether cognitive performance differs between extremely preterm (EPT)/extremely low birth weight (ELBW) children and very preterm (VPT) or very low birth weight (VLBW) children.

METHODS

PubMed and PsycINFO databases were searched for cohort studies comparing IQ and neuropsychological functions in term-born and preterm-born children born after 1994.

RESULTS

At ages three to five years, preterm-born children, compared with term-born ones, had worse IQ mean score (d = -0.77 [95% confidence interval -0.88 to -0.66]), attention, memory, visuomotor integration skill and executive functions. No differences were found between VPT/VLBW and EPT/ELBW children.

CONCLUSION

Preterm-born children showed poorer IQ and neuropsychological functions compared with term-born subjects already at preschool age. The extent of differences is similar to that detected at a later age.

Prenatal Risk Predicts Preschooler Executive Function: A Cascade Model

Little research has considered whether prenatal experience contributes to executive function (EF) development above and beyond postnatal experience. This study tests direct, mediated, and moderated associations between prenatal risk factors and preschool EF and IQ in a longitudinal sample of 1,292 children from the Family Life Project. A composite of prenatal risk factors (i.e., low birth weight, prematurity, maternal emotional problems, maternal prepregnancy obesity, and obstetric complications) significantly predicted EF and IQ at age 3, above quality of the postnatal environment. This relationship was indirect, mediated through infant general cognitive abilities. Quality of the postnatal home and child-care environments did not moderate the cascade model. These findings highlight the role of prenatal experience as a contributor to individual differences in cognitive development.

Neural substrates of early executive function development

In the last decade, advances in neuroimaging technologies have given rise to a large number of research studies that investigate the neural underpinnings of executive function (EF). EF has long been associated with the prefrontal cortex (PFC) and involves both a unified, general element, as well as the distinct, separable elements of working memory, inhibitory control and set shifting. We will highlight the value of utilising advances in neuroimaging techniques to uncover answers to some of the most pressing questions in the field of early EF development. First, this review will explore the development and neural substrates of each element of EF. Second, the structural, anatomical and biochemical changes that occur in the PFC during infancy and throughout childhood will be examined, in order to address the importance of these changes for the development of EF. Third, the importance of connectivity between regions of the PFC and other brain areas in EF development is reviewed. Finally, throughout this review more recent developments in neuroimaging techniques will be addressed, alongside the implications for further elucidating the neural substrates of early EF development in the future.

Network based statistics reveals trophic and neuroprotective effect of early high dose erythropoetin on brain connectivity in very preterm infants

Periventricular white matter injury is common in very preterm infants and it is associated with long term neurodevelopmental impairments. While evidence supports the protective effects of erythropoetin (EPO) in preventing injury, we currently lack the complete understanding of how EPO affects the emergence and maturation of anatomical brain connectivity and function. In this case-control study, connectomic analysis based on diffusion MRI tractography was applied to evaluate the effect of early high-dose EPO in preterm infants. A whole brain, network-level analysis revealed a sub-network of anatomical brain connections in which connectivity strengths were significantly stronger in the EPO group. This distributed network comprised connections predominantly in the frontal and temporal lobe bilaterally, and the effect of EPO was focused on peripheral and feeder connections of the core structural connectivity network. EPO resulted in a globally increased clustering coefficient, higher global and average local efficiency, while higher strength and increased clustering was found for regions in the frontal lobe and cingulate gyrus. The connectivity network most affected by the EPO treatment showed a steeper increase graph theoretical measures with age compared to the placebo group. Our results demonstrate a weak but widespread effect of EPO on the structural connectivity network and a possible trophic effect of EPO reflected by increasing network segregation, predominantly in local connections.

•

Erythropoietin (EPO) is a potential neuroprotective agent in very preterm infants.

•

EPO leads to increased structural brain connectivity in fronto-temporal regions.

•

Clustering coefficient, local and global efficiency increases after EPO treatment.

Executive Function in Relation to White Matter in Preterm and Full Term Children

Background: Executive function (EF) refers to cognitive abilities used to guide goal-directed behavior. Diffusion Tensor Imaging (DTI) provides quantitative characterization of white matter tracts in the brain. Children with preterm birth often have EF impairments and white matter injury. Aim: To examine the degree of association between EF scores and white matter fractional anisotropy (FA) as measured by DTI in children born preterm and term Study design: Cross-sectional study Subjects: Participants, 9-16 years of age, born preterm (n = 25; mean gestational age 28.6 weeks; mean birth weight 1,191 grams), and full term (n = 20) Outcome measures: White matter FA analyzed with Tract-Based Spatial Statistics, a technique that generates a skeleton representing the core of white matter tracts throughout the brain. Behavioral scores from EF tasks examining working memory, spatial memory capacity, and multiple skills from the Stockings of Cambridge. Results: The groups performed comparably on all tasks. In both groups, unfavorable working memory strategy scores were associated with lower FA. Other measures of EF were not associated with whole skeleton FA in either group in either direction. Conclusions: Strategy score on a spatial working memory task was associated with FA in preterm and full term children, suggesting common underlying neurobiology in both groups. Associations were found in frontal-parietal connections and other major tracts. Lack of associations between other EF tasks and FA may be due to variation in how children accomplish these EF tasks. Future research is required to fully understand the neurobiology of EF in children born preterm.

Nurturing the preterm infant brain: leveraging neuroplasticity to improve neurobehavioral outcomes

An intrinsic feature of the developing brain is high susceptibility to environmental influence-known as plasticity. Research indicates cascading disruption to neurological development following preterm (PT) birth; yet, the interactive effects of PT birth and plasticity remain unclear. It is possible that, with regard to neuropsychological outcomes in the PT population, plasticity is a double-edged sword. On one side, high plasticity of rapidly developing neural tissue makes the PT brain more vulnerable to injury resulting from events, including inflammation, hypoxia, and ischemia. On the other side, plasticity may be a mechanism through which positive experience can normalize neurological development for PT children. Much of the available literature on PT neurological development is clinically weighted and focused on diagnostic utility for predicting long-term outcomes. Although diagnostic utility is valuable, research establishing neuroprotective factors is equally beneficial. This review will: (1) detail specific mechanisms through which plasticity is adaptive or maladaptive depending on the experience; (2) integrate research from neuroimaging, intervention, and clinical science fields in a summary of findings suggesting inherent plasticity of the PT brain as a mechanism to improve child outcomes; and (3) summarize how responsive caregiving experiences situate parents as agents of change in normalizing PT infant brain development.

MRI at term equivalent age for predicting long-term neurodevelopmental outcome in preterm infants - a cohort study

Purpose: Preterm infants are at increased risk of adverse neurodevelopmental outcome (NDO). Cranial ultrasound has limited predictability. The purpose of the study is to evaluate whether magnetic resonance imaging (MRI) done at term equivalent age (TEA) predicts NDO at 18-22 months of corrected gestational age (CGA).Materials and methods: This cohort study of preterm infants born at ≤32 weeks of gestation and/or birth weight <1500 grams between April 2011 and August 2012 was conducted in a tertiary care institute in India. MRI done at TEA was reported using objective scoring. NDO at 18-22-month CGA was assessed using Bayley Scale of Infant Development (BSID) version III. Composite score (CS) < 85 in motor, language, or cognition domain was taken as adverse NDO. Association between individual MRI subscores and NDO was evaluated using multiple linear regressions by backward elimination method. Validity of MRI abnormality in predicting adverse NDO was assessed.Results: Out of 94 infants who had MRI at TEA, 56 (60%) underwent BSID III. Mean gestational age was 29.8 ± 2.1 weeks. Median CS of all domains was lower with higher total MRI score. Predictive accuracy for various subscores ranged from 55 to 73%. By multiple regression analysis, signal abnormality was associated with motor delay (β -8.4; p .02) and cystic white matter (WM) changes with motor delay (β -7.3; p .003) and cognitive delay (β -6.1; p .005).Conclusions: Although specificity and negative predictive value were moderate to high across all subscores in MRI to predict the NDO, the accuracy has been only low to moderate, which limits its use as sole predictor.

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.

Neurodevelopmental Outcomes in Early Childhood

Technological advances in neonatal-perinatal medicine have led to a steady increase in the survival of preterm infants. Although the increase in survival is a remarkable success, children born preterm remain at high risk for brain injury and long-term neurodevelopmental deficits. Children born preterm may have abnormal muscle tone or movements, cognitive deficits, language impairments, and behavioral problems. This article reviews neurodevelopmental outcomes and factors that influence outcomes in preterm children during early childhood.

Rapid Infant Prefrontal Cortex Development and Sensitivity to Early Environmental Experience

Over the last fifteen years, the emerging field of developmental cognitive neuroscience has described the relatively late development of prefrontal cortex in children and the relation between gradual structural changes and children's protracted development of prefrontal-dependent skills. Widespread recognition by the broader scientific community of the extended development of prefrontal cortex has led to the overwhelming perception of prefrontal cortex as a "late developing" region of the brain. However, despite its supposedly protracted development, multiple lines of research have converged to suggest that prefrontal cortex development may be particularly susceptible to individual differences in children's early environments. Recent studies demonstrate that the impacts of early adverse environments on prefrontal cortex are present very early in development: within the first year of life. This review provides a comprehensive overview of new neuroimaging evidence demonstrating that prefrontal cortex should be characterized as a "rapidly developing" region of the brain, discusses the converging impacts of early adversity on prefrontal circuits, and presents potential mechanisms via which adverse environments shape both concurrent and long-term measures of prefrontal cortex development. Given that environmentally-induced disparities are present in prefrontal cortex development within the first year of life, translational work in intervention and/or prevention science should focus on intervening early in development to take advantages of this early period of rapid prefrontal development and heightened plasticity.

Goal Setting Deficits at 13 Years in Very Preterm Born Children

OBJECTIVES

Preterm children demonstrate deficits in executive functions including inhibition, working memory, and cognitive flexibility; however, their goal setting abilities (planning, organization, strategic reasoning) remain unclear. This study compared goal setting abilities between very preterm (VP: <30 weeks/<1250 grams) and term born controls during late childhood. Additionally, early risk factors (neonatal brain abnormalities, medical complications, and sex) were examined in relationship to goal setting outcomes within the VP group.

METHODS

Participants included 177 VP and 61 full-term born control children aged 13 years. Goal setting was assessed using several measures of planning, organization, and strategic reasoning. Parents also completed the Behavior Rating Inventory of Executive Function. Regression models were performed to compare groups, with secondary analyses adjusting for potential confounders (sex and social risk), and excluding children with major neurosensory impairment and/or IQ<70. Within the VP group, regression models were performed to examine the relationship between brain abnormalities, medical complications, and sex, on goal setting scores.

RESULTS

The VP group demonstrated a clear pattern of impairment and inefficiency across goal setting measures, consistent with parental report, compared with their full-term born peers. Within the VP group, moderate/severe brain abnormalities on neonatal MRI predicted adverse goal setting outcomes at 13.

CONCLUSIONS

Goal setting difficulties are a significant area of concern in VP children during late childhood. These difficulties are associated with neonatal brain abnormalities, and are likely to have functional consequences academically, socially and vocationally. (JINS, 2018, 24, 372-381).

Prematuridade, Funções Executivas e Qualidade dos Cuidados Parentais: Revisão Sistemática de Literatura

RESUMO Este artigo de revisão visa contextualizar o desenvolvimento das funções executivas (FE) em crianças prematuras, com especial atenção para o efeito dos cuidados parentais. As principais bases eletrônicas foram utilizadas para essa revisão: 31 estudos originais, duas meta-análises, uma meta-síntese e dois artigos de revisão foram identificados. Concluiu-se que as crianças prematuras têm maior risco de disfunção executiva global, sendo a qualidade dos cuidados parentais fundamentais para a modulação das FE, nomeadamente no que concerne às variáveis socioemocionais da interação, como a sensibilidadematerna. Salientam-se ainda as principais limitações dos estudos analisados e apontam-se recomendações para futura investigação sobre os efeitos dos cuidados parentais no desenvolvimento de FE em crianças prematuras.

Neurobiologic Correlates of Attention and Memory Deficits Following Critical Illness in Early Life

OBJECTIVES

Survivors of critical illness in early life are at risk of long-term-memory and attention impairments. However, their neurobiologic substrates remain largely unknown.

DESIGN

A prospective follow-up study.

SETTING

Erasmus MC-Sophia Children's Hospital, Rotterdam, the Netherlands.

PATIENTS

Thirty-eight school-age (8-12 yr) survivors of neonatal extracorporeal membrane oxygenation and/or congenital diaphragmatic hernia with an intelligence quotient greater than or equal to 80 and a below average score (z score ≤ -1.5) on one or more memory tests.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Intelligence, attention, memory, executive functioning, and visuospatial processing were assessed and compared with reference data. White matter microstructure and hippocampal volume were assessed using diffusion tensor imaging and structural MRI, respectively. Global fractional anisotropy was positively associated with selective attention (β = 0.53; p = 0.030) and sustained attention (β = 0.48; p = 0.018). Mean diffusivity in the left parahippocampal region of the cingulum was negatively associated with visuospatial memory, both immediate (β = -0.48; p = 0.030) and delayed recall (β = -0.47; p = 0.030). Mean diffusivity in the parahippocampal region of the cingulum was negatively associated with verbal memory delayed recall (left: β = -0.52, p = 0.021; right: β = -0.52, p = 0.021). Hippocampal volume was positively associated with verbal memory delayed recall (left: β = 0.44, p = 0.037; right: β = 0.67, p = 0.012). Extracorporeal membrane oxygenation treatment or extracorporeal membrane oxygenation type did not influence the structure-function relationships.

CONCLUSIONS

Our findings indicate specific neurobiologic correlates of attention and memory deficits in school-age survivors of neonatal extracorporeal membrane oxygenation and congenital diaphragmatic hernia. A better understanding of the neurobiology following critical illness, both in early and in adult life, may lead to earlier identification of patients at risk for impaired neuropsychological outcome with the use of neurobiologic markers.

Clinical neuroimaging in the preterm infant: Diagnosis and prognosis

Perinatal care advances emerging over the past twenty years have helped to diminish the mortality and severe neurological morbidity of extremely and very preterm neonates (e.g., cystic Periventricular Leukomalacia [c-PVL] and Germinal Matrix Hemorrhage - Intraventricular Hemorrhage [GMH-IVH grade 3-4/4]; 22 to < 32 weeks of gestational age, GA). However, motor and/or cognitive disabilities associated with mild-to-moderate white and gray matter injury are frequently present in this population (e.g., non-cystic Periventricular Leukomalacia [non-cystic PVL], neuronal-axonal injury and GMH-IVH grade 1-2/4). Brain research studies using magnetic resonance imaging (MRI) report that 50% to 80% of extremely and very preterm neonates have diffuse white matter abnormalities (WMA) which correspond to only the minimum grade of severity. Nevertheless, mild-to-moderate diffuse WMA has also been associated with significant affectations of motor and cognitive activities. Due to increased neonatal survival and the intrinsic characteristics of diffuse WMA, there is a growing need to study the brain of the premature infant using non-invasive neuroimaging techniques sensitive to microscopic and/or diffuse lesions. This emerging need has led the scientific community to try to bridge the gap between concepts or ideas from different methodologies and approaches; for instance, neuropathology, neuroimaging and clinical findings. This is evident from the combination of intense pre-clinical and clinicopathologic research along with neonatal neurology and quantitative neuroimaging research. In the following review, we explore literature relating the most frequently observed neuropathological patterns with the recent neuroimaging findings in preterm newborns and infants with perinatal brain injury. Specifically, we focus our discussions on the use of neuroimaging to aid diagnosis, measure morphometric brain damage, and track long-term neurodevelopmental outcomes.

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.

Neonatal diffusion tensor brain imaging predicts later motor outcome in preterm neonates with white matter abnormalities

BACKGROUND

White matter (WM) abnormalities associated with prematurity are one of the most important causes of neurological disability that involves spastic motor deficits in preterm newborns. This study aimed to evaluate regional microstructural changes in diffusion tensor imaging (DTI) associated with WM abnormalities.

METHODS

We prospectively studied extremely low birth weight (ELBW; <1000 g) preterm infants who were admitted to the Neonatal Intensive Care Unit of Hanyang University Hospital between February 2011 and February 2014. WM abnormalities were assessed with conventional magnetic resonance (MR) imaging and DTI near term-equivalent age before discharge. Region-of-interests (ROIs) measurements were performed to examine the regional distribution of fractional anisotropy (FA) values.

RESULTS

Thirty-two out of 72 ELBW infants underwent conventional MR imaging and DTI at term-equivalent age. Ten of these infants developed WM abnormalities associated with prematurity. Five of ten of those with WM abnormalities developed cerebral palsy (CP). DTI in the WM abnormalities with CP showed a significant reduction of mean FA in the genu of the corpus callosum (p = 0.022), the ipsilateral posterior limb of the internal capsule (p = 0.019), and the ipsilateral centrum semiovale (p = 0.012) compared to normal WM and WM abnormalities without CP. In infants having WM abnormalities with CP, early FA values in neonatal DTI revealed abnormalities of the WM regions prior to the manifestation of hemiparesis.

CONCLUSIONS

DTI performed at term equivalent age shows different FA values in WM regions among infants with or without WM abnormalities associated with prematurity and/or CP. Low FA values of ROIs in DTI are related with later development of spastic CP in preterm infants with WM abnormalities.

Changing definitions of long-term follow-up: Should "long term" be even longer?

There have been amazing changes in outcomes of preterm (PT) infants in the past decades. Whereas early studies reported only survival rates, Dr. Julius Hess published the first outcome study of PT infants in Chicago in 1953. Dr. Lubchenco then published the 10-year follow-up of premature infants born in 1947-1953 and identified a 68% handicap rate. As a result of these early studies, the importance of evaluating NICU graduates both for surveillance and as an outcome of trials was recognized. During the 1970s, there was a gradual expansion in the number of follow-up programs in the United States (US) with an increasing number of follow-up studies published. In the 1980s, the importance of multicenter clinical research networks was recognized and the NICHD Neonatal Research Network (NRN) was initiated in 1986. Follow-up protocols, definitions, and outcomes have evolved over the last 30 years and will be reviewed with a focus on NICHD NRN studies.

Creatine, Glutamine plus Glutamate, and Macromolecules Are Decreased in the Central White Matter of Premature Neonates around Term

Preterm birth represents a high risk of neurodevelopmental disabilities when associated with white-matter damage. Recent studies have reported cognitive deficits in children born preterm without brain injury on MRI at term-equivalent age. Understanding the microstructural and metabolic underpinnings of these deficits is essential for their early detection. Here, we used diffusion-weighted imaging and single-voxel 1H magnetic resonance spectroscopy (MRS) to compare brain maturation at term-equivalent age in premature neonates with no evidence of white matter injury on conventional MRI except diffuse excessive high-signal intensity, and normal term neonates. Thirty-two infants, 16 term neonates (mean post-conceptional age at scan: 39.8±1 weeks) and 16 premature neonates (mean gestational age at birth: 29.1±2 weeks, mean post-conceptional age at scan: 39.2±1 weeks) were investigated. The MRI/MRS protocol performed at 1.5T involved diffusion-weighted MRI and localized 1H-MRS with the Point RESolved Spectroscopy (PRESS) sequence. Preterm neonates showed significantly higher ADC values in the temporal white matter (P<0.05), the occipital white matter (P<0.005) and the thalamus (P<0.05). The proton spectrum of the centrum semiovale was characterized by significantly lower taurine/H2O and macromolecules/H2O ratios (P<0.05) at a TE of 30 ms, and reduced (creatine+phosphocreatine)/H2O and (glutamine+glutamate)/H2O ratios (P<0.05) at a TE of 135 ms in the preterm neonates than in full-term neonates. Our findings indicate that premature neonates with normal conventional MRI present a delay in brain maturation affecting the white matter and the thalamus. Their brain metabolic profile is characterized by lower levels of creatine, glutamine plus glutamate, and macromolecules in the centrum semiovale, a finding suggesting altered energy metabolism and protein synthesis.

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.

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.

Associations of Perinatal Clinical and Magnetic Resonance Imaging Measures with Developmental Outcomes in Children Born Very Preterm

OBJECTIVE

To identify perinatal risk factors associated with long-term neurocognitive and behavioral impairments in children born very preterm using a multivariate, partial least squares approach.

STUDY DESIGN

Twenty-seven perinatal clinical and magnetic resonance imaging measures were collected at birth and during the neonatal intensive care stay for 105 neonates born very preterm (≤ 32 weeks gestational age). One-half of the children returned for neuropsychological assessments at 2 and 4 years of age. Parent-reported behavioral measures were also obtained at 4 years of age. Three partial least squares analyses were performed to determine associations between clinical and radiologic measures with cognitive outcomes at 2 and 4 years of age, as well as with behavioral measures at 4 years of age.

RESULTS

Within the first components of each analysis, only intrauterine growth restriction, male sex, and absence of antenatal corticosteroid use were associated with poorer cognitive and language ability at 2 and 4 years of age, accounting for 79.6% and 71.4% of the total variance, respectively. In addition, white matter injury at term-equivalent age contributed to more problematic internalizing behaviors, behavioral symptoms, and impaired executive function at 4 years of age, accounting for 67.9% of the total variance.

CONCLUSIONS

Using this data-driven multivariate approach, specific measures in prenatal and early postnatal life are shown to be selectively and significantly associated with cognitive and behavioral outcomes in children born very preterm. Early detection of risk factors can help inform prognoses of children at greatest risk of long-term impairments.

Attention in 3-Year-Old Children with VLBW and Relationships with Early School Outcomes

AIM

To compare attention skills of children with a very low birth weight (VLBW) with children with a normal birth weight (NBW) when entering primary school, and explore the association of attention skills with school career 2 years later.

METHODS

Participants were 151 children with VLBW and 41 with NBW. Attention was assessed at 3 years and 8 months of corrected age (CA) and school career at 5½ years of CA. Children performed two tests, parents completed three questionnaires, and an assessor systematically observed children's attention.

RESULTS

Children with VLBW had significantly lower mean scores on five of the six measures. Significantly more children with VLBW had scores in the clinical range on the Child Behavior Checklist completed by the parents (13% versus 0%) and scores representing dysfunction on assessor observations (19% versus 2%). At 5½ years of age, 36% of the children with VLBW followed special education or had grade retention. Dysfunctional attention as observed by the assessor was most strongly associated with need for learning support at 5½ years of age.

CONCLUSIONS

At preschool age, children with VLBW have attention difficulties. Attentive behavior at preschool age is a predictor of school career 2 years later.

The contribution of visual processing to academic achievement in adolescents born extremely preterm or extremely low birth weight

Children born extremely preterm (EP, <28 weeks) and/or extremely low birth weight (ELBW, <1000 g) have more academic deficiencies than their term-born peers, which may be due to problems with visual processing. The aim of this study is to determine (1) if visual processing is related to poor academic outcomes in EP/ELBW adolescents, and (2) how much of the variance in academic achievement in EP/ELBW adolescents is explained by visual processing ability after controlling for perinatal risk factors and other known contributors to academic performance, particularly attention and working memory. A geographically determined cohort of 228 surviving EP/ELBW adolescents (mean age 17 years) was studied. The relationships between measures of visual processing (visual acuity, binocular stereopsis, eye convergence, and visual perception) and academic achievement were explored within the EP/ELBW group. Analyses were repeated controlling for perinatal and social risk, and measures of attention and working memory. It was found that visual acuity, convergence and visual perception are related to scores for academic achievement on univariable regression analyses. After controlling for potential confounds (perinatal and social risk, working memory and attention), visual acuity, convergence and visual perception remained associated with reading and math computation, but only convergence and visual perception are related to spelling. The additional variance explained by visual processing is up to 6.6% for reading, 2.7% for spelling, and 2.2% for math computation. None of the visual processing variables or visual motor integration are associated with handwriting on multivariable analysis. Working memory is generally a stronger predictor of reading, spelling, and math computation than visual processing. It was concluded that visual processing difficulties are significantly related to academic outcomes in EP/ELBW adolescents; therefore, specific attention should be paid to academic remediation strategies incorporating the management of working memory and visual processing in EP/ELBW children.

Developmental synergy between thalamic structure and interhemispheric connectivity in the visual system of preterm infants

Thalamic structural co-variation with cortical regions has been demonstrated in preterm infants, but its relationship to cortical function and severity of non-cystic white matter injury (non-cystic WMI) is unclear. The relationship between thalamic morphology and both cortical network synchronization and cortical structural connectivity has not been established. We tested the hypothesis that in preterm neonates, thalamic volume would correlate with primary cortical visual function and microstructural integrity of cortico-cortical visual association pathways. A total of 80 term-equivalent preterm and 44 term-born infants underwent high-resolution structural imaging coupled with visual functional magnetic resonance imaging or diffusion tensor imaging. There was a strong correlation between thalamic volume and primary visual cortical activation in preterms with non-cystic WMI (r = 0.81, p-value = 0.001). Thalamic volume also correlated strongly with interhemispheric cortico-cortical connectivity (splenium) in preterm neonates with a relatively higher severity of non-cystic WMI (p-value < 0.001). In contrast, there was lower correlation between thalamic volume and intrahemispheric cortico-cortical connectivity, including the inferior longitudinal fasciculus and inferior frontal orbital fasciculus. This study shows distinct temporal overlap in the disruption of thalamo-cortical and interhemispheric cortico-cortical connectivity in preterm infants suggesting developmental synergy between thalamic morphology and the emergence of cortical networks in the last trimester.

Outcomes for extremely premature infants

Premature birth is a significant cause of infant and child morbidity and mortality. In the United States, the premature birth rate, which had steadily increased during the 1990s and early 2000s, has decreased annually for 7 years and is now approximately 11.39%. Human viability, defined as gestational age at which the chance of survival is 50%, is currently approximately 23 to 24 weeks in developed countries. Infant girls, on average, have better outcomes than infant boys. A relatively uncomplicated course in the intensive care nursery for an extremely premature infant results in a discharge date close to the prenatal estimated date of confinement. Despite technological advances and efforts of child health experts during the last generation, the extremely premature infant (less than 28 weeks gestation) and extremely low birth weight infant (<1000 g) remain at high risk for death and disability with 30% to 50% mortality and, in survivors, at least 20% to 50% risk of morbidity. The introduction of continuous positive airway pressure, mechanical ventilation, and exogenous surfactant increased survival and spurred the development of neonatal intensive care in the 1970s through the early 1990s. Routine administration of antenatal steroids during premature labor improved neonatal mortality and morbidity in the late 1990s. The recognition that chronic postnatal administration of steroids to infants should be avoided may have improved outcomes in the early 2000s. Evidence from recent trials attempting to define the appropriate target for oxygen saturation in preterm infants suggests arterial oxygen saturation between 91% and 95% (compared with 85%-89%) avoids excess mortality; however, final analyses of data from these trials have not been published, so definitive recommendations are still pending. The development of neonatal neurocritical intensive care units may improve neurocognitive outcomes in this high-risk group. Long-term follow-up to detect and address developmental, learning, behavioral, and social problems is critical for children born at these early gestational ages.The striking similarities in response to extreme prematurity in the lung and brain imply that agents and techniques that benefit one organ are likely to also benefit the other. Finally, because therapy and supportive care continue to change, the outcomes of extremely low birth weight infants are ever evolving. Efforts to minimize injury, preserve growth, and identify interventions focused on antioxidant and anti-inflammatory pathways are now being evaluated. Thus, treating and preventing long-term deficits must be developed in the context of a "moving target."

Self-Reported ADHD Symptoms and Interhemispheric Interaction in Adults: A Dimensional Approach

The present study applied the dimensional approach to test whether self-reported symptoms of Attention Deficit/Hyperactivity Disorder (ADHD) in adults are associated with the speed of interhemispheric interaction. A sample of first grade students (N = 112) completed Conners' Adult ADHD Rating Scales and letter matching reaction time tasks. In the tasks, participants had to match a single target letter displayed below the fixation cross, either on left or right visual field, with one of two letters displayed above the fixation cross, one letter on each visual field. For each task, identical letters were presented either within the same visual field (within hemisphere condition) or across visual fields (across hemisphere condition). Interhemispheric interaction was indexed as the difference in mean reaction time between within and across hemisphere conditions. Comorbid problems such as depression, anxiety, and stress may affect task performance and are controlled for in this study. Findings indicated that self-reported ADHD symptomology, especially hyperactivity, in the presence of stress was weakly but significantly associated with fast interhemispheric interaction.

Neurological outcomes of animal models of uterine artery ligation and relevance to human intrauterine growth restriction: a systematic review

AIM

This review explores the molecular, neurological, and behavioural outcomes in animal models of uterine artery ligation. We analyse the relevance of this type of model to the pathological and functional phenotypes that are consistent with cerebral palsy and its developmental comorbidities in humans.

METHOD

A literature search of the PubMed database was conducted for research using the uterine artery ligation model published between 1990 and 2013. From the studies included, any relevant neuroanatomical and behavioural deficits were then summarized from each document and used for further analysis.

RESULTS

There were 25 papers that met the criteria included for review, and several outcomes were summarized from the results of these papers. Fetuses with growth restriction demonstrated a gradient of reduced body weight with a relative sparing of brain mass. There was a significant reduction in the size of the somatosensory cortex, hippocampus, and corpus callosum. The motor cortex appeared to be spared of identifiable deficits. Apoptotic proteins were upregulated, while those important to neuronal survival, growth, and differentiation were downregulated. Neuronal apoptosis and astrogliosis occurred diffusely throughout the brain regions. White matter injury involved oligodendrocyte precursor maturation arrest, hypomyelination, and an aberrant organization of existing myelin. Animals with growth restriction demonstrated deficits in gait, memory, object recognition, and spatial processing.

INTERPRETATION

This review concludes that neuronal death, white matter injury, motor abnormalities, and cognitive deficits are important outcomes of uterine artery ligation in animal models. Therefore, this is a clinically relevant type of model, as these findings resemble deficits in human cerebral palsy.