Long-term neuropsychological outcomes of very low birth weight: associations with early risks for periventricular brain insults

Biological and environmental factors may affect children's executive function through motor and sensorimotor development: Preterm birth and cerebral palsy

Disruptive biological and environmental factors may undermine the development of children's motor and sensorimotor skills. Since the development of cognitive skills, including executive function, is grounded in early motor and sensorimotor experiences, early delays or impairments in motor and sensorimotor processing often trigger dynamic developmental cascades that lead to suboptimal executive function outcomes. The purpose of this perspective paper is to link early differences in motor/sensorimotor processing to the development of executive function in children born preterm or with cerebral palsy. Uncovering such links in clinical populations would improve our understanding of developmental pathways and key motor and sensorimotor skills that are antecedent and foundational for the development of executive function. This knowledge will allow the refinement of early interventions targeting motor and sensorimotor skills with the goal of proactively improving executive function outcomes in at-risk populations.

Neurodevelopmental outcomes of premature infants with intraventricular hemorrhage across a lifespan

Neurodevelopmental impairment rates remain high among extremely preterm and very low birth weight infants. This review describes the rates of brain injury and neuro-developmental impairment at 2,3 years, early school age, adolescence, and young adulthood for survivors with intraventricular hemorrhage (IVH). Former preterm infants with a history of high-grade IVH are at the greatest risk of adverse neurodevelopmental outcomes. There is variability, however, in definitions of brain injury, methods for assessing brain injury, and definitions of adverse outcomes among multicenter networks. Despite differences in methods described in publications, perinatal grade III-IV intraventricular hemorrhage, post-hemorrhagic hydrocephalus, and white matter injury are consistently associated with increased rates of adverse motor and cognitive outcomes in the first 2,3 years of life, at early school age, in adolescence and early adulthood. Effects of socioeconomic status on outcomes, however, increase with the increasing age of the child. In summary, although preterm survivors of IVH are at an increased risk of adverse outcomes across a lifetime, there is evidence that social and environmental factors contribute to recovery over time.

Effects of gestational age at birth on perinatal structural brain development in healthy term-born babies

Infants born in early term (37-38 weeks gestation) experience slower neurodevelopment than those born at full term (40-41 weeks gestation). While this could be due to higher perinatal morbidity, gestational age at birth may also have a direct effect on the brain. Here we characterise brain volume and white matter correlates of gestational age at birth in healthy term-born neonates and their relationship to later neurodevelopmental outcome using T2 and diffusion weighted MRI acquired in the neonatal period from a cohort (n = 454) of healthy babies born at term age (>37 weeks gestation) and scanned between 1 and 41 days after birth. Images were analysed using tensor-based morphometry and tract-based spatial statistics. Neurodevelopment was assessed at age 18 months using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Infants born earlier had higher relative ventricular volume and lower relative brain volume in the deep grey matter, cerebellum and brainstem. Earlier birth was also associated with lower fractional anisotropy, higher mean, axial, and radial diffusivity in major white matter tracts. Gestational age at birth was positively associated with all Bayley-III subscales at age 18 months. Regression models predicting outcome from gestational age at birth were significantly improved after adding neuroimaging features associated with gestational age at birth. This work adds to the body of evidence of the impact of early term birth and highlights the importance of considering the effect of gestational age at birth in future neuroimaging studies including term-born babies.

Very Preterm Early Motor Repertoire and Neurodevelopmental Outcomes at 8 Years

BACKGROUND AND OBJECTIVES

Children born very preterm (<32 weeks' gestation) have more neurodevelopmental problems compared with term-born peers. Aberrant fidgety movements (FMs) are associated with adverse motor outcomes in children born very preterm. However, associations of aberrant FMs combined with additional movements and postures to give a motor optimality score-revised (MOS-R) with school-aged cognitive and motor outcomes are unclear. Our aim with this study was to determine those associations.

METHODS

Of 118 infants born <30 weeks' gestation recruited into a randomized controlled trial of early intervention, 97 had a general movements assessment at 3 months' corrected age and were eligible for this study. Early motor repertoire including FMs and MOS-R were scored from videos of infant's spontaneous movement at 3 months' corrected age. At 8 years' corrected age, cognitive and motor performances were evaluated. Associations of early FMs and MOS-R with outcomes at 8 years were determined using linear regression.

RESULTS

Seventy-eight (80%) infants with early motor repertoire data had neurodevelopmental assessments at 8 years. A higher MOS-R, and favorable components of the individual subscales of the MOS-R, including the presence of normal FMs, were associated with better performance for general cognition, attention, working memory, executive function and motor function at 8 years; eg, presence of normal FMs was associated with a 21.6 points higher general conceptual ability score (95% confidence interval: 12.8-30.5; P < .001) compared with absent FMs.

CONCLUSIONS

Favorable early motor repertoire of infants born <30 weeks is strongly associated with improved cognitive and motor performance at 8 years.

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

BACKGROUND

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

AIMS

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

STUDY DESIGN

Longitudinal cohort study.

SUBJECTS

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

OUTCOME MEASURES

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

RESULTS

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

CONCLUSION

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

The Role of Humidity in the Management of Premature Neonates in a Rural Incubator

Background

While growing inside the uterus, the human fetus floats in amniotic fluid, and the mother maintains a stable temperature of 37 °C and a humidity of 100%. In most neonatal incubators, a stable temperature is maintained but not the humidity. We hypothesised that maintaining a humidity of 70% and a temperature of 32 °C in incubator rooms might improve the outcomes related to low birth weight (LBW) neonates.

Methods

In this interventional study, 30 preterm LBW neonates delivered at different gestational ages were studied. Instead of an incubator box, we converted one entire room (14’/9’/10’) into an incubator. Three 200-watt bulbs were fixed to the wall at a height of 1 meter from babies. The room thermometer was mounted on the wall close to babies. The room temperature was maintained at 32 °C by turning the lights on or off as required. Wet cotton sheets (4’ × 6’) were spread on the opposite wall with the support of a stand. A hygrometer was fixed to the wall near to babies, and the humidity of the room was maintained at 70-80%.

The hydration and nutrition needs of the babies were met with IV fluids/nasogastric (NG) tube feeding. Antenatal steroids were given to all mothers before the completion of 38 weeks. Babies were discharged when they were stable, and further care was given at home with similar arrangements of maintaining temperature and humidity. Birth weights, the number of babies that developed neonatal respiratory distress syndrome (NRDS), hypothermia, septicaemia, neonatal intensive care unit (NICU) admission days, home incubator days, and neonatal deaths were recorded and compared with the findings in the existing literature.

Results

Among the 30 neonates studied, birth weights ranged from 1.00 to 1.95 kg. Twenty-three babies developed NRDS, and four babies developed septicaemia; NICU days ranged from five to 28 days, and at-home incubator days ranged from 15 to 60 days. One baby succumbed to the illness.

Conclusion

Open nursing care of functionally premature neonates at room temperature of 32 °C and humidity of 70% is a cost-effective method that can lead to excellent outcomes.

White matter injury in infants with intraventricular haemorrhage: mechanisms and therapies

Intraventricular haemorrhage (IVH) continues to be a major complication of prematurity that can result in cerebral palsy and cognitive impairment in survivors. No optimal therapy exists to prevent IVH or to treat its consequences. IVH varies in severity and can present as a bleed confined to the germinal matrix, small-to-large IVH or periventricular haemorrhagic infarction. Moderate-to-severe haemorrhage dilates the ventricle and damages the periventricular white matter. This white matter injury results from a constellation of blood-induced pathological reactions, including oxidative stress, glutamate excitotoxicity, inflammation, perturbed signalling pathways and remodelling of the extracellular matrix. Potential therapies for IVH are currently undergoing investigation in preclinical models and evidence from clinical trials suggests that stem cell treatment and/or endoscopic removal of clots from the cerebral ventricles could transform the outcome of infants with IVH. This Review presents an integrated view of new insights into the mechanisms underlying white matter injury in premature infants with IVH and highlights the importance of early detection of disability and immediate intervention in optimizing the outcomes of IVH survivors.

Neonatal Adverse Outcomes, Neonatal Birth Risks, and Socioeconomic Status: Combined Influence on Preterm Infants' Cognitive, Language, and Motor Development in Brazil

BACKGROUND

This study extended previous research by investigating the combined effects of neonatal birth risks, neonatal adverse outcomes, and socioeconomic status on preterm neurodevelopment.

METHOD

A total of 184 preterm infants were assessed using the Bayley Scales of Infant Development III in a follow-up clinic in southern Brazil. Structural equation modeling was conducted with 3 latent variables (neonatal birth risks, neonatal adverse outcomes, and socioeconomic status) and 3 outcomes (cognitive, language, and motor development).

RESULTS

The analyses showed that neonatal adverse outcomes were associated with infants' cognitive (b = -0.45, P < .001), language (b = -0.23, P = .001), and motor (b = -0.51, P < .001) development. Socioeconomic status also explained the variances (cognitive: b = 0.20, P = .006; language: b = 0.28, P = .001; and motor: b = 0.21, P = .004), whereas neonatal birth risks remained significant only in the motor development (b = 0.15, P = .040).

CONCLUSION

This study suggests that the most evident contributors to poor neurodevelopment were adverse outcomes and socioeconomic risk factors.

Low Birth Weight and Psychoeducational Outcomes: Investigation of an African American Birth Cohort

African Americans experience more than double the prevalence of low birth weight (LBW)/premature birth compared to their Caucasian counterparts, reflecting a public health crisis and a significant social justice concern. However, there is a paucity of LBW outcome studies in African American samples. There are even fewer that investigate developmental outcomes within the moderately LBW range (i.e., 1500–2500 g), the most prevalent category of LBW births. This study investigates the relationship between LBW and various psychoeducational outcomes in a prospectively designed African American birth cohort. Multivariate logit analyses of the Johns Hopkins University Pathways to Adulthood study compared LBW children with normal birth weight children on a number of outcome measures at seven and 8 years of age. Results revealed that children born within the lowest birth weight category produced the most adverse findings, from both a statistical and clinical standpoint, on measures of cognitive ability, academic achievement, speech, language, auditory processing, and visual–motor integration.

Executive function deficits in children born preterm or at low birthweight: a meta-analysis

AIM

To investigate the magnitude of executive function deficits and their dependency on gestational age, sex, age at assessment, and year of birth for children born preterm and/or at low birthweight.

METHOD

PubMed, PsychINFO, Web of Science, and ERIC were searched for studies reporting on executive functions in children born preterm/low birthweight and term controls born in 1990 and later, assessed at a mean age of 4 years or higher. Studies were included if five or more studies reported on the same executive function measures.

RESULTS

Thirty-five studies (3360 children born preterm/low birthweight, 2812 controls) were included. Children born preterm/low birthweight performed 0.5 standardized mean difference (SMD) lower on working memory and cognitive flexibility and 0.4 SMD lower on inhibition. SMDs for these executive functions did not significantly differ from each other. Meta-regression showed that heterogeneity in SMDs for working memory and inhibition could not be explained by study differences in gestational age, sex, age at assessment, or year of birth.

INTERPRETATION

Children born preterm/low birthweight since 1990 perform half a SMD below term-born peers on executive function, which does not seem to improve with more recent advances in medical care or with increasing age.

WHAT THIS PAPER ADDS

Children born preterm/low birthweight perform below term-born children on core executive functions. Lower gestational age or male sex are not risk factors for poorer executive functions. Executive function difficulties in children born preterm/low birthweight remain stable across childhood. Executive function difficulties are similar for children born recently and children born in earlier eras.

A Comparison of Developmental Outcomes of Adolescent Neonatal Intensive Care Unit Survivors Born with a Congenital Heart Defect or Born Preterm

OBJECTIVE

To compare cognitive, motor, behavioral, and functional outcomes of adolescents born with a congenital heart defect (CHD) and adolescents born preterm.

STUDY DESIGN

Adolescents (11-19 years old) born with a CHD requiring open-heart surgery during infancy (n = 80) or born preterm ≤29 weeks of gestational age (n = 128) between 1991 and 1999 underwent a cross-sectional evaluation of cognitive (Leiter International Performance Scale-Revised), motor (Movement Assessment Battery for Children-II), behavioral (Strengths and Difficulties Questionnaire), and functional (Vineland Adaptive Behavior Scale-II) outcomes. Independent samples t tests and Pearson χ² or Fisher exact tests were used to compare mean scores and proportions of impairment, respectively, between groups.

RESULTS

Adolescents born with a CHD and adolescents born preterm had similar cognitive, motor, behavioral, and functional outcomes. Cognitive deficits were detected in 14.3% of adolescents born with a CHD and 11.8% of adolescents born preterm. Motor difficulties were detected in 43.5% of adolescents born with a CHD and 50% of adolescents born preterm. Behavioral problems were found in 23.7% of adolescents in the CHD group and 22.9% in the preterm group. Functional limitations were detected in 12% of adolescents born with a CHD and 7.3% of adolescents born preterm.

CONCLUSIONS

Adolescents born with a CHD or born preterm have similar profiles of developmental deficits. These findings highlight the importance of providing long-term surveillance to both populations and guide the provision of appropriate educational and rehabilitation services to better ameliorate long-term developmental difficulties.

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

Preterm-born individuals are at risk for poorer executive functions. Longitudinal studies investigating whether preterm-born individuals present persistent cognitive deficits, or a transient delay of development are scarce. We assessed developmental trajectories of executive functions (inhibition, working memory, cognitive flexibility) in 29 very preterm-born individuals (<32 weeks' gestation) and 25 term-born controls longitudinally over two time points, namely in childhood (7-12 years of age, TP1) and adolescence (13-16 years of age, TP2). Individual changes in executive functions were examined using relative difference scores (TP2 - TP1) / TP1). There was a significantly stronger improvement of inhibition (U = 477, p = .024) and cognitive flexibility (U = 312, p = .029) between childhood and adolescence in very preterm-born individuals than in term-born controls. Preterm-born individuals improved their performance in the domain of cognitive flexibility significantly more often (76%) between childhood and adolescence than controls (31%, χ² = 8.6, p = .003). Controls worsened significantly more often (36%) in the domain of inhibition than the preterm group (14%, χ² = 4.8, p = .028). Results indicate that healthy preterm-born individuals show prolonged development of executive functions throughout childhood up into adolescence.

Predictors for delayed linguistic skills in very preterm infants

BACKGROUND

Preterm-born children are at higher risk for impaired linguistic abilities than are their term-born peers. The aim of the current study was to determine early predictors for delayed linguistic skills in very preterm-born preschool children.

METHODS

Between January 2005 and November 2010 all very preterm infants born at < 32 weeks gestation in Tyrol were prospectively enrolled (n = 421); 248 of them had a detailed examination at the age of five years including cognitive assessment (Wechsler Preschool and Primary Scale of Intelligence, third edition (WPPSI-III) or Snijders-Oomen Nonverbal Intelligence Tests (SON-R)) as well as a screening test for language skills (Bielefelder screening for early diagnosis of reading problems and weak spelling (BISC)). The association between pre-and postnatal factors and poor performance on the BISC assessment was analyzed by means of logistic regression analysis.

RESULTS

Of the 248 children 79 (31.8%) showed delayed literacy precursor skills. Male sex, gestational age, retinopathy of prematurity (ROP) grades 3-4 and low maternal education were predictive for delayed linguistic skills at 5 years of age in the multivariate analysis.

CONCLUSION

This study identified predictors for delayed literacy precursor skills. These data support the finding that in very preterm infants pre-and perinatal as well as sociodemographic factors account for linguistic skills in the preschool period.

An update on pulmonary and neurodevelopmental outcomes of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common complication of extreme prematurity, and its rate is not improving, despite advances in perinatal intensive care. Children with BPD diagnosed in the neonatal period have higher risks for hospitalizations for respiratory problems over the first few years of life, and they have more asthma in later childhood. Neonates diagnosed with BPD have substantial airway obstruction on lung function testing in later childhood and early adulthood, and many are destined to develop adult chronic obstructive pulmonary disease. Survivors with neonatal BPD have more adverse motor function, worse cognitive development and poorer academic progress than those without BPD. Long-term outcomes for children born extremely preterm will improve if the rate of BPD can be substantially reduced.

Cognitive outcomes in children and adolescents born very preterm: a meta-analysis

AIM

To estimate the association between very preterm birth (<32wks' gestation) and intelligence, executive functioning, and processing speed throughout childhood and adolescence, and to examine the effects of gestational age, birthweight, and age at assessment.

METHOD

Studies were included if children were born at earlier than 32 weeks' gestation, aged 4 to 17 years, had an age-matched term control group, and if the studies used standardized measures, were published in an English-language peer-reviewed journal, and placed no restrictions on participants based on task performance.

RESULTS

We evaluated 6163 children born very preterm and 5471 term-born controls from 60 studies. Children born very preterm scored 0.82 SDs (95% confidence interval [CI] 0.74-0.90; p<0.001) lower on intelligence tests, 0.51 SDs (95% CI 0.44-0.58; p<0.001) lower on measures of executive functioning, and 0.49 SDs (95% CI 0.39-0.60; p<0.001) lower on measures of processing speed than term-born controls. Gestational age and birthweight were associated with study effect size in intelligence and executive functioning of younger children only. Age at assessment was not associated with study effect size.

INTERPRETATION

Children born very preterm have medium to large deficits in these cognitive domains.

WHAT THIS PAPER ADDS

This meta-analysis is centred on very preterm birth and three cognitive domains. The three critical cognitive domains are intelligence, executive functioning, and processing speed.

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).

Antenatal and Neonatal Antecedents of Executive Dysfunctions in Extremely Preterm Children

To find out why children born extremely preterm are at heightened risk of executive dysfunctions, the authors assessed 716 children who were 10 years old born extremely preterm whose IQ was ≥ 70. A working memory dysfunction (n = 169), an inhibition dysfunction (n = 360), a switching dysfunction (355), and all 3 (executive dysfunction; n = 107) were defined on the basis of Z-scores ≤ -1 on the Differential Ability Scales-II Working Memory composite, and/or on the NEPSY-II Inhibition-Inhibition and Inhibition-Switching subtests. All risk profiles include an indicator of socioeconomic disadvantage. The risk profile of each of the 3 individual dysfunctions includes an indicator of the newborn's immaturity, and the risk profiles of the inhibition dysfunction and switching dysfunction also include an indicator of inflammation. Only the switching dysfunction was associated with fetal growth restriction. The risk factors for executive dysfunction can be subsumed under the 4 themes of socioeconomic disadvantage, immaturity/vulnerability, inflammation, and fetal growth restriction.

Do Infants Born Very Premature and Who Have Very Low Birth Weight Catch Up With Their Full Term Peers in Their Language Abilities by Early School Age?

PURPOSE

This study examined the extent to which children born preterm (< 37 weeks) and/or who have low birth weight (< 2,500 g) catch up with their full term peers in terms of their language abilities at early school age (≥ 5 to < 9 years).

METHOD

A systematic literature search identified empirical studies that fit the inclusion criteria. Data from the tests/questionnaires used for meta-analysis spanned the following language categories: total language score, expressive language, receptive language, pragmatics, phonological awareness, and grammar. The means (standard deviations) were extracted from the studies and were converted to mean difference and 95% confidence intervals to test for overall effect.

RESULTS

Sixteen studies met the inclusionary criteria, for a total of 2,739 participants, of which 1,224 were born full term and 1,515 were born preterm. It is important to note that the preterm cohort represented very preterm infants who have a very low birth weight. The meta-analysis found that preterm infants scored significantly worse on total language (p < .001), receptive language (p < .001), expressive language (p < .001), phonological awareness (p < .001), and grammar (p = .03) than their full term peers. However, preterm infants did not score significantly worse than their peers on their pragmatics (p = .19).

CONCLUSIONS

Children born VPT and who have VLBW perform worse than their peers on their total language, receptive language, expressive language, phonological awareness, and grammar abilities by early school age. This information is important for speech-language pathologists to consider as children born prematurely reach school age.

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.

Neurocognitive Correlates of Attention-Deficit Hyperactivity Disorder Symptoms in Children Born at Extremely Low Gestational Age

OBJECTIVE

Compared with children born near term, those born extremely preterm (EP) are at much higher risk for attention-deficit hyperactivity disorder (ADHD). Little information is available about differences in neuropsychological outcomes among EP children with and without ADHD. Our analyses aimed to evaluate the neuropsychological correlates of ADHD symptoms in extremely low gestational age newborns (ELGANs).

METHODS

We obtained Child Symptom Inventory-4 reports from parents (n = 871) and teachers (n = 634) of 10-year-old children born before the 28th week of gestation. Participants completed standardized assessments of neurocognitive and academic functioning.

RESULTS

In the total sample, children who screened positive for ADHD symptoms were at increased risk for neurocognitive limitations. These associations were weaker when the sample was limited to those with intelligence quotient (IQ) ≥70 or ≥85. Even those with IQ ≥85 who screened positive for ADHD symptoms were more likely than their peers to have deficits on the DAS-II Working Memory Cluster and the NEPSY-II Auditory Response subtest. The risks for impaired academic performance (Z ≤ -1) on components of the WIAT-III were 2-to-3 times higher in this group than among ELGANs not classified as having ADHD symptoms.

CONCLUSION

Among children born EP, those with ADHD symptoms are more likely to have global neurocognitive impairment. When IQ is within normal limits, ADHD symptoms are associated with deficits in executive functioning skills. These findings highlight a group at risk for executive functioning deficits and related academic difficulties, even in the absence of intellectual disability.

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.

Links between motor control and classroom behaviors: Moderation by low birth weight

It is unclear from past research on effortful control whether one of its components, motor control, independently contributes to adaptive classroom behaviors. The goal of this study was to identify associations between early motor control, measured by the walk-a-line task at age 3, and teacher-reported learning-related behaviors (approaches to learning and attention problems) and behavior problems in kindergarten classrooms. Models tested whether children who were vulnerable to poorer learning behaviors and more behavior problems due to having been born low birth weight benefited more, less, or the same as other children from better motor control. Data were drawn from the national Fragile Families and Child-Wellbeing Study (n = 751). Regression models indicated that motor control was significantly associated with better approaches to learning and fewer behavior problems. Children who were low birth weight benefitted more than normal birth weight children from better motor control with respect to their approaches to learning, but equally with respect to behavior problems. Additionally, for low but not normal birth weight children, better motor control predicted fewer attention problems. These findings suggest that motor control follows a compensatory model of development for low birth weight children and classroom behaviors.

Executive function relates to surface area of frontal and temporal cortex in very-low-birth-weight late teenagers

BACKGROUND

Being born with very low birth weight (VLBW; birth weight (BW) ≤1500 g) is associated with increased risk of maldevelopment of the immature brain which may affect neurological functioning. Deficits in attention and executive function problems have been reported in VLBW survivors compared with healthy subjects.

AIMS

The aim of this study was to evaluate attention and executive functions and to relate the clinical test results to cortical morphometry findings in VLBW young adults compared with term-born controls.

STUDY DESIGN

Prospective follow-up study of three year cohorts of VLBW and control children from birth to adulthood.

OUTCOME MEASURES

A comprehensive neuropsychological test battery was administered to 55 VLBW subjects born preterm (mean BW: 1217 g) and 81 term-born controls (mean BW: 3707 g) at age 19-20. Cerebral MRI was successfully obtained in 46 VLBW subjects and 61 controls. The FreeSurfer software package was applied for the cortical analyses based on T1-weighted MRI images.

RESULTS

The VLBW group obtained inferior scores on 15 of the 29 neuropsychological measures assessing attention and executive function and on both the attention and executive function domain scores. We found positive correlations between the executive function domain score and cortical surface area, especially in the antero-medial frontal and the temporal lobes of the brain in the VLBW group.

CONCLUSION

Young adults born with VLBW show deficits in attention and executive function compared with controls. The executive problems were related to smaller cortical surface area in brain regions known to be involved in higher order cognitive functioning.

The Effects of the Severity of Periventricular Leukomalacia on the Neuropsychological Outcomes of Preterm Children

This study investigates the developmental outcomes of preterm children according to severity of periventricular leukomalacia. One hundred preterm children with periventricular leukomalacia evident on brain magnetic resonance imaging and who had undergone neuropsychologic evaluation were selected. Intellectual disability was noted in 27.8% of the children with mild periventricular leukomalacia, 53.2% with moderate periventricular leukomalacia, and 77.1% with severe periventricular leukomalacia. The rates of major neurodevelopmental impairments such as cerebral palsy or intellectual disability were related to the severity of periventricular leukomalacia but not to gestational age or epilepsy. There were significant differences in the intelligence quotient (IQ) and social maturity quotient between 3 groups of periventricular leukomalacia. The performance IQ was significantly lower than the verbal IQ. Behavioral problems were noted in about one-third of the children but the rate was not related with the severity of periventricular leukomalacia. Our study revealed the significant associations between severity of periventricular leukomalacia and cognitive and social adaptive functions in the preterm children.

Perinatal chronic hypoxia induces cortical inflammation, hypomyelination, and peripheral myelin-specific T cell autoreactivity

pCH is an important risk factor for brain injury and long-term morbidity in children, occurring during the developmental stages of neurogenesis, neuronal migration, and myelination. We show that a rodent model of pCH results in an early decrease in mature myelin. Although pCH does increase progenitor oligodendrocytes in the developing brain, BrdU labeling revealed a loss in dividing progenitor oligodendrocytes, indicating a defect in mature cell replacement and myelinogenesis. Mice continued to exhibited hypomyelination, concomitant with long-term impairment of motor function, weeks after cessation of pCH. The implication of a novel neuroimmunologic interplay, pCH also induced a significant egress of infiltrating CD4 T cells into the developing brain. This pCH-mediated neuroinflammation included oligodendrocyte-directed autoimmunity, with an increase in peripheral myelin-specific CD4 T cells. Thus, both the loss of available, mature, myelin-producing glial cells and an active increase in autoreactive, myelin-specific CD4 T cell infiltration into pCH brains may contribute to early pCH-induced hypomyelination in the developing CNS. The elucidation of potential mechanisms of hypoxia-driven autoimmunity will expand our understanding of the neuroimmune axis during perinatal CNS disease states that may contribute to long-term functional disability.

Perinatal medical variables predict executive function within a sample of preschoolers born very low birth weight

The goal was to identify perinatal predictors of early executive dysfunction in preschoolers born very low birth weight. Fifty-seven preschoolers completed 3 executive function tasks: Dimensional Change Card Sort-Separated (inhibition, working memory, and cognitive flexibility), Bear Dragon (inhibition and working memory), and Gift Delay Open (inhibition). Relationships between executive function and perinatal medical severity factors (gestational age, days on ventilation, size for gestational age, maternal steroids, and number of surgeries) and chronological age were investigated by multiple linear regression and logistic regression. Different perinatal medical severity factors were predictive of executive function tasks, with gestational age predicting Bear Dragon and Gift Open; and number of surgeries and maternal steroids predicting performance on Dimensional Change Card Sort-Separated. By understanding the relationship between perinatal medical severity factors and preschool executive outcomes, we can identify children at highest risk for future executive dysfunction, thereby focusing targeted early intervention services.

Executive function in adolescents born <1000 g or <28 weeks: a prospective cohort study

BACKGROUND AND OBJECTIVES

Extremely preterm (EP; <28 weeks) birth and extremely low birth weight (ELBW; <1000 g) are risk factors for poor cognitive outcomes, including in executive function (EF; higher-order cognitive skills necessary for goal-directed, adaptive functioning and important for academic and behavioral-emotional outcomes). We aimed to (1) extend the limited data on EF in EP/ELBW survivors in adolescence compared with normal birth weight controls, and (2) determine changes in EF between ages 8 and 17 years in both groups.

METHODS

Two hundred twenty-eight EP/ELBW and 166 control adolescents (mean age, 17 years) from a prospective geographical cohort were assessed with multiple EF tasks, and parent- and self-ratings of behavioral EF. The Rey Complex Figure and Behavior Rating Inventory of Executive Function parent report were also administered at age 8 years, enabling examination of change in scores between childhood and adolescence.

RESULTS

EP/ELBW adolescents performed more poorly than controls in verbal processing speed, attentional control, cognitive flexibility, and goal-setting (effect sizes, -0.7 to -0.2 SD), but not psychomotor reaction time. Group differences were of similar magnitude across tasks. From childhood to late adolescence, EP/ELBW children improved their accuracy of the Rey Complex Figure copy more than controls. According to parents, executive behaviors were largely stable over time in both groups.

CONCLUSIONS

Adolescents born EP/ELBW have poorer EF skills across multiple domains than controls. From childhood to late adolescence, different aspects of EF improved, but others did not, underscoring the need for multidomain, longitudinal assessments in this high-risk population.

Adaptive mechanisms of developing brain: cerebral lateralization in the prematurely-born

Preterm birth results in alterations in neural connectivity, but the impact of prematurity on the functional organization of the developing brain has yet to be explored. To test the hypothesis that preterm birth alters cortical organization during the late second and third trimesters of gestation, we interrogated cerebral lateralization at rest in 26 very preterm subjects (birth weight 500-1500g) with no evidence of brain injury and 25 healthy term control subjects at term equivalent age. Employing an unbiased voxel-based measure of functional connectivity, these data demonstrated that cerebral lateralization is impaired in the prematurely-born. At term equivalent age, preterm neonates showed significantly less lateralization in regions subserving both receptive and expressive language, left Brodmann (BA) areas insula-BA22-BA21 and L BA45-BA47 (p<0.05 corrected for multiple comparisons for both). Exploratory region of interest analyses demonstrated significantly less inter-hemispheric connectivity from L BA22 to R BA22 in preterm infants compared to term controls (p<0.005) and from R BA22 to its homolog (p<0.005). L BA22, Wernicke's area, was more strongly connected to R BA39, foreshadowing neural networks for language in preterm subjects at school age, adolescence and young adulthood. For these very preterm neonates born at less than 30weeks' PMA, the degree of prematurity had no influence on lateralization in these differential regions.

Adolescents born prematurely with isolated grade 2 haemorrhage in the early 1990s face increased risks of learning challenges

AIM

To compare the impact of low-grade haemorrhage on neurocognitive function in 16-year-old adolescents born preterm, by grade of intraventricular haemorrhage, and term controls.

METHODS

We evaluated 338 preterm adolescents (birth weight 600-1250 g) for intelligence, executive function and memory tasks. Eleven had grade 3-4 haemorrhage, 44 had grade 2, 31 had grade 1, and 251 had no haemorrhage. Group comparisons were made with 102 term age-matched controls, and regression models used to identify the risk that low-grade haemorrhage posed for cognitive, executive function and memory deficits.

RESULTS

Preterm adolescents with grade 2 haemorrhage had higher deficit rates of verbal intelligence, receptive vocabulary, phonemic fluency, cognitive flexibility and phonological fluency than preterm adolescents with grade 1 or no haemorrhage, compared with term controls. After excluding preterm adolescents with both grade 2 haemorrhage and cystic periventricular leukomalacia, those with isolated grade 2 haemorrhage remained at greater risk of cognitive and executive function deficits than term controls and of cognitive deficits than preterm adolescents with no haemorrhage.

CONCLUSION

Our findings suggest that preterm adolescents born in the early 1990s with isolated grade 2 haemorrhage are at increased risk of learning challenges, including cognitive and executive function deficits.

Individual cognitive patterns and developmental trajectories after preterm birth

Cognitive outcome after preterm birth is heterogeneous, and group level analyses may disguise individual variability in development. Using a person-oriented approach, this study investigated individual cognitive patterns and developmental trajectories from preschool age to late adolescence. As part of a prospective longitudinal study, 118 adolescents born preterm, with a birth weight < 1,500 g, participated in neuropsychological assessments at age 5½ years and at 18 years. At each age, four cognitive indices, two tapping general ability and two tapping executive functions, were formed to reflect each individual's cognitive profile. Cluster analyses were performed at each age separately, and individual movements between clusters across time were investigated. At both 5½ and 18 years, six distinct, and similar, cognitive patterns were identified. Executive functions were a weakness for some but not all subgroups, and verbal ability was a strength primarily among those whose overall performance fell within the normal range. Overall, cognitive ability at 5½ years was highly predictive of ability at age 18. Those who performed at low levels at 5½ years did not catch up but rather deteriorated in relative performance. Over half of the individuals who performed above the norm at 5½ years improved their relative performance by age 18. Among those performing around the norm at 5½ years, half improved their relative performance over time, whereas the other half faced increased problems, indicating a need for further developmental monitoring. Perinatal factors were not conclusively related to outcome, stressing the need for cognitive follow-up assessment of the preterm-born child before school entry.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.

DoMINO: Donor milk for improved neurodevelopmental outcomes

BACKGROUND

Provision of mother's own milk is the optimal way to feed infants, including very low birth weight infants (VLBW, <1500 g). Importantly for VLBW infants, who are at elevated risk of neurologic sequelae, mother's own milk has been shown to enhance neurocognitive development. Unfortunately, the majority of mothers of VLBW infants are unable to provide an adequate supply of milk and thus supplementation with formula or donor milk is necessary. Given the association between mother's own milk and neurodevelopment, it is important to ascertain whether provision of human donor milk as a supplement may yield superior neurodevelopmental outcomes compared to formula.Our primary hypothesis is that VLBW infants fed pasteurized donor milk compared to preterm formula as a supplement to mother's own milk for 90 days or until hospital discharge, whichever comes first, will have an improved cognitive outcome as measured at 18 months corrected age on the Bayley Scales of Infant Development, 3(rd) ed. Secondary hypotheses are that the use of pasteurized donor milk will: (1) reduce a composite of death and serious morbidity; (2) support growth; and (3) improve language and motor development. Exploratory research questions include: Will use of pasteurized donor milk: (1) influence feeding tolerance and nutrient intake (2) have an acceptable cost effectiveness from a comprehensive societal perspective?

METHODS/DESIGN

DoMINO is a multi-centre, intent-to-treat, double blinded, randomized control trial. VLBW infants (n = 363) were randomized within four days of birth to either (1) pasteurized donor milk or (2) preterm formula whenever mother's own milk was unavailable. Study recruitment began in October 2010 and was completed in December 2012. The 90 day feeding intervention is complete and long-term follow-up is underway.

DISCUSSION

Preterm birth and its complications are a leading cause long-term morbidity among Canadian children. Strategies to mitigate this risk are urgently required. As mother's own milk has been shown to improve neurodevelopment, it is essential to ascertain whether pasteurized donor milk will confer the same advantage over formula without undue risks and at acceptable costs. Knowledge translation from this trial will be pivotal in setting donor milk policy in Canada and beyond.

TRIAL REGISTRATION

ISRCTN35317141; Registered 10 August 2010.

Neuropsychological outcomes of children born very preterm

Considerable research has investigated the consequences of being born very preterm (VP; <32 weeks of gestation), especially in relation to cognitive functioning. While numerous cognitive and neuropsychological outcome studies have been published, it is important to consider methodological issues when reviewing this research, as the generalizability of the studies varies greatly. This article describes the nature of cognitive difficulties confronting VP children, both in terms of the frequency and severity of deficits. The breadth of cognitive difficulties reported in this population implies a generalized cognitive impairment; however, the presence of selective or primary cognitive deficits is discussed. It is concluded that whereas mortality and neonatal morbidity rates have decreased significantly in VP infants in recent decades, these children continue to be at significant risk for cognitive impairments and need to be closely monitored throughout childhood.

Neuropsychological deficits in young adults born small-for-gestational age (SGA) at term

Reduced IQ, learning difficulties and poor school performance have been reported in small-for-gestational-age (SGA) subjects. However, few studies include a comprehensive neuropsychological assessment. Our aim was to study neuropsychological functioning in young adults born SGA at term. A comprehensive neuropsychological test battery was administered to 58 SGA subjects (birth weight <10th centile) born at term, and 81 term non-SGA controls (birth weight ≥10th centile). The SGA group obtained significantly (p < .01) lower scores on the attention, executive and memory domains compared to non-SGA controls and showed higher risk of obtaining scores below -1.5 SD on the memory domain (odds ratio = 13.3, 95% confidence interval: 1.57, 112.47). At a subtest level, the SGA group obtained lower scores on most neuropsychological tests, with significant differences on 6 of 46 measures: the Trail Making Test 3 (letter sequencing), the Wechsler Memory Scale mental control and the auditory immediate memory scale, the Design Fluency, the Stroop 3 (inhibition) and the Visual Motor Integration (VMI) motor coordination subtest. Young adults born SGA score more poorly on neuropsychological tests compared with non-SGA controls. Differences were modest, with more significant differences in the memory domain.

Relation of neural structure to persistently low academic achievement: a longitudinal study of children with differing birth weights

OBJECTIVE

This study examined the relation of cerebral tissue reductions associated with VLBW to patterns of growth in core academic domains.

METHOD

Children born <750 g, 750 to 1,499 g, or >2,500 g completed measures of calculation, mathematical problem solving, and word decoding at time points spanning middle childhood and adolescence. K. A. Espy, H. Fang, D. Charak, N. M. Minich, and H. G. Taylor (2009, Growth mixture modeling of academic achievement in children of varying birth weight risk, Neuropsychology, Vol. 23, pp. 460-474) used growth mixture modeling to identify two growth trajectories (clusters) for each academic domain: an average achievement trajectory and a persistently low trajectory. In this study, 97 of the same participants underwent magnetic resonance imaging (MRI) in late adolescence, and cerebral tissue volumes were used to predict the probability of low growth cluster membership for each domain.

RESULTS

Adjusting for whole brain volume (wbv), each 1-cm(3) reduction in caudate volume was associated with a 1.7- to 2.1-fold increase in the odds of low cluster membership for each domain. Each 1-mm(2) decrease in corpus callosum surface area increased these odds approximately 1.02-fold. Reduced cerebellar white matter volume was associated specifically with low calculation and decoding growth, and reduced cerebral white matter volume was associated with low calculation growth. Findings were similar when analyses were confined to the VLBW groups.

CONCLUSIONS

Reduced volume of structures involved in connectivity, executive attention, and motor control may contribute to heterogeneous academic trajectories among children with VLBW.

Attention difficulties in a contemporary geographic cohort of adolescents born extremely preterm/extremely low birth weight

The aim of this study was to evaluate attention difficulties in a contemporary geographic cohort of adolescents born extremely preterm (EP, <28 weeks' gestation) or extremely low birth weight (ELBW, birth weight <1000 g). The EP/ELBW group included 228 adolescents (mean age = 17.0 years) born in Victoria, Australia in 1991 and 1992. The control group were 166 adolescents (mean age = 17.4 years) born of normal birth weight (birth weight >2499 g) who were recruited in the newborn period and matched to the EP/ELBW group on date of birth, gender, language spoken and health insurance status. Participants were assessed on measures of selective, sustained, and executive (shift and divided) attention, and parents and participants completed behavioral reports. The EP/ELBW group performed more poorly across tests of selective and executive attention, had greater rates of clinically significant difficulties compared with the control group, and also had greater behavioral attention problems as reported by parents. Neonatal risk factors were weakly associated with attention outcomes. In conclusion, higher rates of attention impairments are observed in individuals born EP/ELBW well into adolescence and may have consequences for their transition to adulthood.

Spectrum of short- and long-term brain pathology and long-term behavioral deficits in male repeated hypoxic rats closely resembling human extreme prematurity

Brain injury in the premature infant is associated with a high risk of neurodevelopmental disability. Previous small-animal models of brain injury attributable to extreme prematurity typically fail to generate a spectrum of pathology and behavior that closely resembles that observed in humans, although they provide initial answers to numerous cellular, molecular, and therapeutic questions. We tested the hypothesis that exposure of rats to repeated hypoxia from postnatal day 1 (P1) to P3 models the characteristic white matter neuropathological injury, gray matter volume loss, and memory deficits seen in children born extremely prematurely. Male Sprague Dawley rats were exposed to repeated hypoxia or repeated normoxia from P1 to P3. The absolute number of pre-oligodendrocytes and mature oligodendrocytes, the surface area and g-ratio of myelin, the absolute volume of cerebral white and gray matter, and the absolute number of cerebral neurons were quantified stereologically. Spatial memory was investigated on a radial arm maze. Rats exposed to repeated hypoxia had a significant loss of (1) pre-oligodendrocytes at P4, (2) cerebral white matter volume and myelin at P14, (3) cerebral cortical and striatal gray matter volume without neuronal loss at P14, and (4) cerebral myelin and memory deficits in adulthood. Decreased myelin was correlated with increased attention deficit hyperactivity disorder-like hyperactivity. This new small-animal model of extreme prematurity generates a spectrum of short- and long-term pathology and behavior that closely resembles that observed in humans. This new rat model provides a clinically relevant tool to investigate numerous cellular, molecular, and therapeutic questions on brain injury attributable to extreme prematurity.

Outcomes of infants born at 22 and 23 weeks' gestation

OBJECTIVE

To provide instructive information on death and neurodevelopmental outcomes of infants born at 22 and 23 weeks' gestational age.

METHODS

The study cohort consisted of 1057 infants born at 22 to 25 weeks in the Neonatal Research Network, Japan. Neurodevelopmental impairment (NDI) at 36 to 42 months' chronological age was defined as any of the following: cerebral palsy, hearing impairment, visual impairment, and a developmental quotient <70. A systematic review was performed by using databases of publications of cohort studies with neonatal and neurodevelopmental outcomes at 22 and 23 weeks.

RESULTS

Numbers and incidences (%) of infants with death or NDI were 60 (80%) at 22 weeks and 156 (64%) at 23 weeks. In logistic regression analysis, gestational ages of 22 weeks (odds ratio [OR]: 5.40; 95% confidence interval [CI]: 2.48-11.76) and 23 weeks (OR: 2.14; 95% CI: 1.38-3.32) were associated with increased risk of death or NDI compared with 24 weeks, but a gestational age of 25 weeks (OR: 0.65; 95% CI: 0.45-0.95) was associated with decreased risk of death or NDI. In the systematic review, the medians (range) of the incidence of death or NDI in 8 cohorts were 99% (90%-100%) at 22 weeks and 98% (67%-100%) at 23 weeks.

CONCLUSIONS

Infants born at 22 and 23 weeks' gestation were at higher risk of death or NDI than infants at born at 24 weeks. However, outcomes were improved compared with those in previous studies. There is a need for additional discussions on interventions for infants born at 22 or 23 weeks' gestation.

Neonatal brain abnormalities and memory and learning outcomes at 7 years in children born very preterm

Using prospective longitudinal data from 198 very preterm and 70 full term children, this study characterised the memory and learning abilities of very preterm children at 7 years of age in both verbal and visual domains. The relationship between the extent of brain abnormalities on neonatal magnetic resonance imaging (MRI) and memory and learning outcomes at 7 years of age in very preterm children was also investigated. Neonatal MRI scans were qualitatively assessed for global, white-matter, cortical grey-matter, deep grey-matter, and cerebellar abnormalities. Very preterm children performed less well on measures of immediate memory, working memory, long-term memory, and learning compared with term-born controls. Neonatal brain abnormalities, and in particular deep grey-matter abnormality, were associated with poorer memory and learning performance at 7 years in very preterm children. Findings support the importance of cerebral neonatal pathology for predicting later memory and learning function.