Executive functioning in school-aged children who were born very preterm or with extremely low birth weight in the 1990s

Using heart rate variability to predict neurological outcomes in preterm infants: a scoping review

Infants born preterm are at higher risk of neurological complications, including intraventricular haemorrhage and white matter injury. After discharge, these infants may experience adverse neurodevelopmental outcomes and exhibit lower educational attainment. Early detection of brain injury and accurate prediction of neurodevelopmental impairment would allow early intervention and support. Heart rate variability (HRV) describes the variation of time intervals between each subsequent heartbeat. HRV is controlled by the autonomic nervous system, which may be affected by hypoxia and compromised blood flow. While HRV has primarily been investigated in neonatal sepsis, the association between HRV, brain injury and neurodevelopmental outcomes in preterm infants is less established. The present scoping review examines the utility of HRV monitoring for predicting short-term and long-term neurological outcomes in preterm infants. Following systematic search of Medline, Embase, Web of Science and the Cochrane Library, 15 studies were included. Nine studies examined the relationship between HRV and brain injury, with all but two showed an association. Eight studies examined the relationship between HRV and long-term outcomes and all eight found an association. This scoping review suggests that decreased HRV in the neonatal period is associated with short- and long-term neurodevelopmental outcomes in preterm infants. IMPACT: Changes in heart rate variability correlate with the occurrence of intraventricular haemorrhage in preterm infants. A decrease in heart rate variability may precede the development of intraventricular haemorrhage. Alterations in heart rate variability correlate with long-term neurodevelopmental outcomes. Significant variability exists in metrics used in assessing heart rate variability.

Grade 7 school performance of children born preterm: a retrospective Canadian Cohort study

IMPORTANCE

Data on the middle school outcomes of preterm children are limited and have methodologic issues.

OBJECTIVE

To study the association between preterm birth and grade 7 school performance.

METHODS

A retrospective population-based cohort study of children born in Manitoba, Canada between 1994 and 2006 using their grade 7 school performance data. A secondary sibling cohort was created comprising children born preterm and their full-term siblings. Primary exposure was preterm birth categorized as <28, 28-33 and 34-36 weeks gestation. The two co-primary grade 7 outcome measures were: not meeting the mathematics competencies, and not meeting the student engagement competencies. Multivariable logistic regression models tested the association between preterm birth and both co-primary outcomes; adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

7653 preterm (gestational age median [IQR]: 35 weeks [34,36]) and 110,313 term (40 [39,40]) were included. 43% of < 28 weeks, 18% of 28-33 weeks and 17% of 34-36 weeks had the mathematics co-primary outcome compared to 13% of term children. The corresponding % for the student engagement outcome were 42%, 24%, 24% and 24% respectively. Preterm birth was associated with the mathematics (<28 weeks: 5.48, 3.89-7.70; 28-33 weeks: 1.47, 1.27-1.70; 34-36 weeks: 1.26, 1.16-1.35) and student engagement outcomes (<28 weeks: 2.49, 1.76-3.51; 28-33 weeks: 1.21, 1.06-1.39; 34-36 weeks: 1.09, 1.01-1.16). However, there was no difference in outcomes among the sibling cohort.

CONCLUSIONS AND RELEVANCE

Children born preterm had lower grade 7 performance compared to children born term in this population-based cohort. Screening and supports for them in their middle school years are warranted.

Effect of tactile and/or kinesthetic stimulation therapy of preterm infants on their parents' anxiety and depressive symptoms: A systematic review

BACKGROUND

In the case of preterm birth, the idealized postnatal period is replaced by an anxious and even traumatic experience for parents. Higher prevalence of parental anxiety, postnatal depression, and posttraumatic stress disorder has been observed in mothers of preterm infants up to 18 months after childbirth. There is increasing evidence that proprioceptive stimulation has a beneficial effect on preterms' short-term outcomes. Could this care also have an impact on parental anxiety and depressive symptoms? We reviewed recent publications on the impact on parents' anxiety and depressive symptoms of delivering tactile and/or kinesthetic stimulation to their premature newborn.

METHODS

We conducted a systematic review by searching the PubMed, PsycInfo, Scopus, ScienceDirect and Google Scholar databases for English-language publications from the past 10 years. We focused on the mothers or fathers of infants born preterm (before 37 weeks of gestation) who provided tactile and/or kinesthetic stimulation to their premature newborn in the neonatal intensive care unit. Relevant outcomes were the parents' anxiety, stress, depressive symptoms, and symptoms of posttraumatic stress disorder, assessed with reliable standardized inventories.

RESULTS

Eleven articles were included in the systematic review. Results suggested a beneficial effect of parents' early tactile and kinesthetic stimulation of their preterm infants.

CONCLUSIONS

These interventions may act as protective factors against the occurrence of anxiety and depressive symptoms in parents and deserve to be studied further in this population.

Executive functions assessment in very preterm children at school age: A pilot study about a clinical and experimental approach

While the survival rate of very preterm (VPT) infants has increased in the last decades, they are still at risk of developing long-term neurodevelopmental impairments, especially regarding self-regulatory abilities, and goal-directed behaviors. These skills rely on executive functions (EFs), an umbrella term encompassing the core capacities for inhibition, shifting, and working memory. Existing comprehensive tests are time-consuming and therefore not suitable for all pediatric neuropsychological assessments. The Flanker task is an experimental computer game having the advantage to last less than ten minutes while giving multiple EFs measures. Here, we tested the potency of this task in thirty-one VPT children aged 8-10 years during their clinical assessment. First, we found that VPT children performed in the norm for most clinical tests (i.e., WISC-V, BRIEF, and NEPSY) except for the CPT-3 where they were slower with more omission errors, which could indicate inattentiveness. Second, some Flanker task scores were correlated with standardized clinical testing without resisting to multiple comparisons correction. Finally, compared to full-term children, VPT children showed poorer performance in global EFs measure and lower accuracy in the Flanker task. These findings suggest that this child-friendly version of the Flanker task demonstrated a reasonable sensitivity in capturing EFs with good discrimination between VPT and term children despite VPT children's mild difficulties. It may represent a promising tool for neuropsychological assessments and be suitable as a screening test, providing further validating larger studies. Moreover, while VPT schoolchildren globally display normal intelligence, subtle difficulties that seem to relate to EFs are observed.

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.

Neurobiological perspective on the development of executive functions

Executive functions are a set of top-down cognitive processes necessary for emotional self-regulation and goal-directed behaviour supporting, among others, academic abilities. Premature infants are at high risk for subsequent cognitive, psychosocial, or behavioural problems even in the absence of medical complications and in spite of normal brain imaging. Given that this is a sensitive period of brain growth and maturation, these factors may place preterm infants at high risk for executive function dysfunction, disrupted long-term development, and lower academic achievements. Therefore, careful attention to interventions at this age is essential for intact executive functions and academic development.

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.

Protocol for a prospective multicenter longitudinal randomized controlled trial (CALIN) of sensory-tonic stimulation to foster parent child interactions and social cognition in very premature infants

Introduction

Premature birth is associated with long-term somatic and neurological disorders, including cognitive, social and behavioral impairments. Moreover, the mothers of infants born preterm exhibit a higher prevalence of anxiety and depressive symptoms after birth. Early rehabilitation, developmental care, and parenting support have already been shown to have a positive impact on neurological outcome. However, no randomized controlled study has so far assessed the effects on parenting and long-term neurological outcomes of proprioceptive stimulation to trigger positive brain plasticity in very preterm babies. The CALIN project will therefore investigate the impact of sensory-tonic stimulation (STS) of extremely preterm infants by their parents on child parent interactions, infants' morphological and functional brain development and subsequent cognition (including social cognition), and parents' anxiety and depressive symptoms in the postpartum period.

Methods and analysis

Infants born between 25 and 32 weeks of gestation will be randomly assigned to the "STS + Kangaroo care" or "Kangaroo care" group. The primary endpoint, child and parent interactions, will be rated at 12 months corrected age using the Coding Interactive Behavior system. Secondary endpoints include: 1/functional and anatomical brain maturation sequentially assessed during neonatal hospitalization using electroencephalogram (EEG), amplitude-integrated EEG (aEEG), cranial ultrasound and MRI performed at term-corrected age, 2/social and cognitive outcomes assessed at 15 months, 2, 4 and 6 years, and 3/parents' anxiety and depressive symptoms assessed at 7 ± 1 weeks after birth, using dedicated questionnaires.

Ethics and dissemination

This study was approved by the French Ethics Committee for the Protection of Persons on 18 October 2021. It is registered with the French National Agency for the Safety of Medicines and Health Products (ANSM; no. 2020-A00382-37). The registry number on ClinicalTrials.gov is NCT04380051.

Grade 3 school performance among children born preterm: a population-based cohort study

OBJECTIVE

To study the association between prematurity and grade 3 school performance in a contemporary cohort of children.

METHODS

Population-based retrospective cohort study in Manitoba, Canada. Children born between 1999 and 2011 who had their grade 3 school performance data available were eligible. Preterm birth (<37 weeks) was the exposure of interest assessed using multivariable logistic regression models. Our primary outcomes were 'needs ongoing help' or 'outside the range' in at least two of each of the (1) four numeracy and (2) three reading competencies.

RESULTS

Of the 186 956 eligible children, 101 436 children (7187 preterm (gestational age, median (IQR) 35 weeks (34, 36)) and 94 249 term (40 weeks (39,40)) were included. Overall, 19% of preterm and 14% of term children had the numeracy outcome (adjusted OR (aOR) 1.38; 95% CI 1.29 to 1.47, p<0.001), while 19% and 13% had the reading outcome (aOR 1.38; 1.29 to 1.48, p<0.001). These differences showed a gestational age gradient. Gestational age (for numeracy, <28 weeks aOR 4.93 (3.45 to 7.03), 28-33 weeks 1.72 (1.50 to 1.98), 34-36 weeks 1.24 (1.15 to 1.34); for reading, <28 weeks 3.51 (2.40 to 5.14), 28-33 weeks 1.72 (1.49 to 1.98), 34-36 weeks 1.24 (1.17-1.37)), male sex, small for gestational age and maternal medical and sociodemographic factors were associated with the numeracy and reading outcomes in this cohort.

CONCLUSIONS AND RELEVANCE

Children born preterm had poorer performance in grade 3 numeracy and reading proficiencies than children born full term. All children born preterm, not just those born extremely preterm, should be screened for reading and numeracy performance in school and strategies implemented to address any deficits.

School Readiness Among Children Born Preterm in Manitoba, Canada

Importance

Children born preterm may experience learning challenges at school. However, there is a paucity of data on the school readiness of these children as they prepare to begin grade 1.

Objective

To examine the association between prematurity and school readiness in a population-based cohort of children.

Design, Setting, and Participants

This cohort study was conducted in the province of Manitoba, Canada, and involved 2 cohorts of children in kindergarten at the time of data collection. The population-based cohort included children born between January 1, 2000, and December 31, 2011, whose school readiness was assessed in kindergarten using the Early Development Instrument (EDI) data. The sibling cohort comprised children born preterm and their closest-in-age siblings born full term. Data were analyzed between March 12 and September 28, 2021.

Exposures

Preterm birth, defined as gestational age (GA) less than 37 weeks.

Main Outcomes and Measures

The primary outcome was vulnerability in the EDI, defined as a score below the tenth percentile of the Canadian population norms for any 1 or more of the 5 EDI domains (physical health and well-being, social competence, emotional maturity, language and cognitive development, and communication skills and general knowledge). Logistic regression models were used to identify the factors associated with vulnerability in the EDI. P values were adjusted for multiplicity using the Simes false discovery method.

Results

Of 86 829 eligible children, 63 277 were included, of whom 4352 were preterm (mean [SD] GA, 34 [2] weeks; 2315 boys [53%]) and 58 925 were full term (mean [SD] GA, 39 (1) weeks; 29 885 boys [51%]). Overall, 35% of children (1536 of 4352) born preterm were vulnerable in the EDI compared with 28% of children (16 449 of 58 925) born full term (adjusted odds ratio [AOR], 1.32; 95% CI, 1.23-1.41; P < .001]). Compared with children born full term, those born preterm had a higher percentage of vulnerability in each of the 5 EDI domains. In the population-based cohort, prematurity (34-36 weeks' GA: AOR, 1.23 [95% CI, 1.14-1.33]; <34 weeks' GA: AOR, 1.72 [95% CI, 1.48-1.99]), male sex (AOR, 2.24; 95% CI, 2.16-2.33), small for gestational age (AOR, 1.31; 95% CI, 1.23-1.40), and various maternal medical and sociodemographic factors were associated with EDI vulnerability. In the sibling cohort, EDI outcomes were similar for both children born preterm and their siblings born full term except for the communication skills and general knowledge domain (AOR, 1.39; 95% CI, 1.07-1.80) and Multiple Challenge Index (AOR, 1.43; 95% CI, 1.06-1.92), whereas male sex (AOR, 2.19; 95% CI, 1.62-2.96) and maternal age at delivery (AOR, 1.53; 95% CI, 1.38-1.70) were associated with EDI vulnerability.

Conclusions and Relevance

Results of this study suggest that, in a population-based cohort, children born preterm had a lower school-readiness rate than children born full term, but this difference was not observed in the sibling cohort. Child and maternal factors were associated with lack of school readiness among this population-based cohort.

Attention and social communication skills of very preterm infants after training attention control: Bayesian analyses of a feasibility study

Background

Very preterm (VP) infants (born 28 to <32 weeks of gestation) are at risk of cognitive delays and lower educational attainments. These risks are linked to anomalies in attention and information processing that emerge in the first years of life. Early interventions targeting attention functioning may equip VP infants with key building blocks for later attainments.

Methods

We tested the feasibility of a randomised trial where VP infants took part in a computerised cognitive procedure to train attention control. Ten healthy VP infants aged approximately 12 months (corrected age) and randomly allocated with 1:1 ratio to the training (interactive computerised presentations) or an active control procedure completed the study. Before and after the training programme, participating infants completed a battery of screen-based attention tests, naturalistic attention and communication tasks, and temperament assessments. In a previous study we analysed the data concerning feasibility (e.g. recruitment and retention). In the paper presented here we considered the infants’ performance and used Bayesian regression in order to provide credible treatment estimates considering the data collected.

Results

Estimates indicate moderate treatment effects in visual memory: compared to controls, trained infants displayed improvements equivalent to 0.59 SD units. Trained infants also improved in their abilities to attend to less salient stimuli presentations by 0.82 SD units, compared to controls. However, results did not indicate relevant gains in attention habituation or disengagement. We also reported moderate improvements in focused attention during naturalistic tasks, and in directing other people’s attention to shared objects.

Discussion

The results warrant further investigation concerning the effectiveness of training attention control in VP infants, extending this line of research beyond our small and homogeneous sample of healthy VP infants. This study also emphasises the utility of Bayesian approaches in estimating potentially relevant effects in small samples or exploratory studies. The scope for further research on early attention control training is discussed in light of studies indicating VP children’s susceptibility to positive environmental inputs.

Trial registration

Registration ID: NCT03896490. Retrospectively registered at Clinical Trials Protocol Registration and Results System (clinicaltrials.gov).

Self-reported executive function problems in adults born very low birthweight

BACKGROUND

Executive function difficulties are common among children born very preterm and/or very low birthweight (<1500 g; VLBW), but little is known about whether they persist into adulthood.

OBJECTIVES

Examine the nature and pattern of self-reported executive functioning at 23 and 28 years of age using data from a national cohort study of adults born VLBW and a comparison group of same-age full-term (FT) born adults. Also examined were associations between executive function difficulties and socio-economic outcomes.

METHODS

All infants born VLBW in New Zealand during 1986 were prospectively included in an audit of retinopathy of prematurity (n = 413), with 250 (77% of survivors) followed to median age 28 years. A comparison group of FT adults was also recruited at age 23 and followed to 28 years (n = 100). Across both adult assessments, executive functioning was assessed using the Behaviour Rating Inventory of Executive Function-Adult Version (BRIEF-A) and analysed with semi-parametric models to examine the effects of age and group on executive function.

RESULTS

At 23 and 28 years, VLBW adults had increased risk of executive function impairment compared with FT adults in behaviour regulation (relative risk [CI] 2.37, 95% confidence interval (CI)1.27, 4.45), meta-cognition (RR 6.03, 95% CI 2.18, 16.78) and global functioning (RR 3.20, 95% CI 1.40, 7.28). Impaired global executive functioning was associated with lower socio-economic status (regression estimate [b] = -0.43, 95% CI -0.59, -0.27) and a reduced likelihood of home ownership by age 28 years (RR 0.98, 95% CI 0.96, 1.00), even after controlling for sex, ethnicity and parental socio-economic backgrounds for both groups.

CONCLUSION(S)

VLBW-born adults continue to experience more executive function difficulties in their everyday life relative to term controls at age 28 years. These difficulties were negatively associated with their socio-economic opportunities as young adults.

Associations of Maternal Milk Feeding With Neurodevelopmental Outcomes at 7 Years of Age in Former Preterm Infants

IMPORTANCE

Maternal milk feeding may have unique long-term neurodevelopmental benefits in very preterm infants.

OBJECTIVE

To examine the extent to which maternal milk feeding after very preterm birth is associated with cognitive, academic, and behavioral outcomes at school age.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study assessed 586 infants born at less than 33 weeks' gestation at 5 Australian perinatal centers and enrolled in the Docosahexaenoic Acid for Improvement of Neurodevelopmental Outcomes study (January 1, 2001, to December 31, 2005) who were evaluated at a corrected age of 7 years. The statistical analysis was completed on January 19, 2022.

EXPOSURES

Maternal milk intake, including mean volume (milliliters per kilogram per day) during neonatal hospitalization and total duration (in months).

MAIN OUTCOMES AND MEASURES

Neurodevelopmental outcomes at 7 years of age were (1) IQ (Wechsler Abbreviated Scale of Intelligence), (2) academic achievement (Wide Range Achievement Test, Fourth Edition), (3) symptoms of attention-deficit/hyperactivity disorder (ADHD) (Conners Third Edition ADHD Index, parent reported), (4) executive function (Behavior Rating Inventory of Executive Functioning, parent reported), and (5) behavior (Strengths and Difficulties Questionnaire, parent reported).

RESULTS

A total of 586 infants (mean [SD] gestational age at birth, 29.6 [2.3] weeks; 314 male [53.6%]) born to 486 mothers (mean [SD] age, 30.6 [5.5] years; 447 [92.0%] White) were included. Mean (SD) maternal milk intake in the neonatal intensive care unit was 99 (48) mL/kg daily, and mean (SD) maternal milk duration was 5.1 (5.4) months. Mean (SD) full-scale IQ was 98.5 (13.3) points. After covariate adjustment, higher maternal milk intake during the neonatal hospitalization was associated with higher performance IQ (0.67 points per additional 25 mL/kg daily; 95% CI, 0.10-1.23 points), reading scores (1.14 points per 25 mL/kg daily; 95% CI, 0.39-1.89 points), and math scores (0.76 points per 25 mL/kg daily; 95% CI, 0.14-1.37 points) and fewer ADHD symptoms (-1.08 points per 25 mL/kg daily; 95% CI, -1.96 to -0.20 points). Longer duration of maternal milk intake was associated with higher reading (0.33 points per additional month; 95% CI, 0.03-0.63 points), spelling (0.31 points per month; 95% CI, 0.01-0.62 points), and math (0.30 points per month; 95% CI, 0.03-0.58 points) scores. Maternal milk was not associated with improved full-scale IQ, verbal IQ, executive function, or behavior. Most associations were stronger among infants born at lower gestational ages, particularly less than 30 weeks (interaction P values <.01).

CONCLUSIONS AND RELEVANCE

In this cohort study of preterm infants, maternal milk feeding during the neonatal hospitalization and after discharge were associated with better school-age performance IQ and academic achievement and with a reduction in ADHD symptoms, particularly among infants born at less than 30 weeks' gestation.

Water and Meadow Views Both Afford Perceived but Not Performance-Based Attention Restoration: Results From Two Experimental Studies

Attention Restoration Theory proposes that exposure to natural environments helps to restore attention. For sustained attention—the ongoing application of focus to a task, the effect appears to be modest, and the underlying mechanisms of attention restoration remain unclear. Exposure to nature may improve attention performance through many means: modulation of alertness and one’s connection to nature were investigated here, in two separate studies. In both studies, participants performed the Sustained Attention to Response Task (SART) before and immediately after viewing a meadow, ocean, or urban image for 40 s, and then completed the Perceived Restorativeness Scale. In Study 1 (n = 68), an eye-tracker recorded the participants’ tonic pupil diameter during the SARTs, providing a measure of alertness. In Study 2 (n = 186), the effects of connectedness to nature on SART performance and perceived restoration were studied. In both studies, the image viewed was not associated with participants’ sustained attention performance; both nature images were perceived as equally restorative, and more restorative than the urban image. The image viewed was not associated with changes in alertness. Connectedness to nature was not associated with sustained attention performance, but it did moderate the relation between viewing the natural images and perceived restorativeness; participants reporting a higher connection to nature also reported feeling more restored after viewing the nature, but not the urban, images. Dissociation was found between the physiological and behavioral measures and the perceived restorativeness of the images. The results suggest that restoration associated with nature exposure is not associated with modulation of alertness but is associated with connectedness with nature.

Auditory Processing of the Brain Is Enhanced by Parental Singing for Preterm Infants

As the human auditory system is highly malleable in infancy, perinatal risk factors, such as preterm birth, may affect auditory development. In comparison to healthy full-term infants, preterm infants show abnormal auditory brain responses at term age, which may have long-term detrimental outcomes. To achieve an optimal neonatal care environment for preterm-born infants, many early interventions have been developed. Musical interventions developed for neonatal intensive care units (NICUs) have shown beneficial effects on vital functions and weight gain of preterm infants and might also influence basic auditory processing and thereby enhance outcomes. In the present study, we tested the effect of parental singing during kangaroo care on auditory processing of standardized audio stimuli. Preterm infants (born between 24 and 32 weeks of gestation) were randomized to singing intervention (n = 13) or control (n = 8) groups. The auditory processing was tested using two audio paradigms assessed with magnetoencephalography (MEG) at term corresponding age. To verify that the paradigms elicit responses in MEG, we studied 12 healthy full-term infants. In the singing intervention group, parents were instructed by a music therapist twice a week for 4 weeks to sing or hum during kangaroo care in an infant-directed way. The control group received standard kangaroo care. The results show that the infants in the singing intervention group show larger neural responses than those in the control group when controlling for the total amount of singing during kangaroo care. Our findings suggest that incorporating singing into kangaroo care may be beneficial for preterm infants, but the effect may not be due to exposure to singing but instead positive parenting, improved parental self-esteem and improved caregiver sensitivity.

Neurobehavioral Phenotype and Dysexecutive Syndrome of Preterm Children: Comorbidity or Trigger? An Update

Premature birth is a worldwide public health priority. One in ten children is born before 37 weeks of gestational age and, in developed countries, survival rates without major neonatal morbidity are increasing. Although severe sequelae associated with these births have decreased, their neurobehavioral difficulties, often associated in multiple fields, remain stable but still widespread. These neurobehavioral difficulties hamper the normal development of academic achievements and societal integration and intensify the children's needs for rehabilitation during their preschool and academic years. Severe sequelae increase when gestational age decreases. This is even truer if the socio-cultural background is impeded by low income, education and language skills as compared with defined averages. However, moderate and/or minor neurocognitive and/or behavioral difficulties are almost identical for a moderate or a late preterm birth. Obtaining a better clinical description of neurobehavioral characteristics of those pretermly born, once they reach preschool age, is essential to detect behavioral issues as well as early specific cognitive difficulties (working memory, planning, inhibition, language expression and reception, attention and fine motor skills, etc.). Such information would provide a better understanding of the executive functions' role in brain connectivity, neurodevelopment and neuroanatomical correlation with premature encephalopathy.

Early Influences of Microbiota on White Matter Development in Germ-Free Piglets

Abnormalities in the prefrontal cortex (PFC), as well as the underlying white matter (WM) tracts, lie at the intersection of many neurodevelopmental disorders. The influence of microorganisms on brain development has recently been brought into the clinical and research spotlight as alterations in commensal microbiota are implicated in such disorders, including autism spectrum disorders, schizophrenia, depression, and anxiety via the gut-brain axis. In addition, gut dysbiosis is common in preterm birth patients who often display diffuse WM injury and delayed WM maturation in critical tracts including those within the PFC and corpus callosum. Microbial colonization of the gut aligns with ongoing postnatal processes of oligodendrogenesis and the peak of brain myelination in humans; however, the influence of microbiota on gyral WM development remains elusive. Here, we develop and validate a neonatal germ-free swine model to address these issues, as piglets share key similarities in WM volume, developmental trajectories, and distribution to humans. We find significant region-specific reductions, and sexually dimorphic trends, in WM volume, oligodendrogenesis, and mature oligodendrocyte numbers in germ-free piglets during a key postnatal epoch of myelination. Our findings indicate that microbiota plays a critical role in promoting WM development during early life when the brain is vulnerable to environmental insults that can result in an array of disabilities manifesting later in life.

The impact of premature extrauterine exposure on infants' stimulus-evoked brain activity across multiple sensory systems

Prematurity can result in widespread neurodevelopmental impairment, with the impact of premature extrauterine exposure on brain function detectable in infancy. A range of neurodynamic and haemodynamic functional brain measures have previously been employed to study the neurodevelopmental impact of prematurity, with methodological and analytical heterogeneity across studies obscuring how multiple sensory systems are affected. Here, we outline a standardised template analysis approach to measure evoked response magnitudes for visual, tactile, and noxious stimulation in individual infants (n = 15) using EEG. By applying these templates longitudinally to an independent cohort of very preterm infants (n = 10), we observe that the evoked response template magnitudes are significantly associated with age-related maturation. Finally, in a cross-sectional study we show that the visual and tactile response template magnitudes differ between a cohort of infants who are age-matched at the time of study but who differ according to whether they are born during the very preterm or late preterm period (n = 10 and 8 respectively). These findings demonstrate the significant impact of premature extrauterine exposure on brain function and suggest that prematurity can accelerate maturation of the visual and tactile sensory system in infants born very prematurely. This study highlights the value of using a standardised multi-modal evoked-activity analysis approach to assess premature neurodevelopment, and will likely complement resting-state EEG and behavioural assessments in the study of the functional impact of developmental care interventions.

Cognitive and academic outcomes of children born extremely preterm

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

A randomized EPIREMED protocol study on the long-term visuo spatial effects of very preterm children with a working memory deficit

BACKGROUND

Very preterm children generally perform poorly in executive functions and particularly in working memory. Adaptive training tasks encouraging these children to work continuously on their personal working memory capacity can be very useful. Above all in preschool-age children, several cognitive training programs focused on improving working memory capacity. Cogmed is a computerized visuospatial cognitive training program that improves working memory in children and adolescents with attention-deficit/hyperactivity disorder. The main objective is to assess the long-term effects (18 months) of cognitive training (Cogmed) on visuospatial processing in preschool-age very preterm children with working memory impairment.

METHODS

The EPIREMED study is a prospective, randomized, controlled, multicentric trial nested in a population based epidemiological survey. An intervention group (Cogmed cognitive training) and a control group (standard care management) will compare children aged 5½ to 6 years, born between 24- and 34-weeks' gestational age, with a global intelligence quotient > 70 and a working memory index < 85. The study will include 166 children from national study EPIPAGE-2 (Epidemiological Study on Small Gestational Ages). The intervention consists of 25 sessions administered over a 5- to 8-week period. The primary endpoint will be the visuospatial processing, assessed by the score of the visuospatial index: score of the WPPSI-IV (Wechsler Preschool and Primary Scale of Intelligence). The secondary endpoints will allow to assess the executive functions, language and abilities, infant behavior, quality of life assessment, school performance and parental anxiety.

DISCUSSION

This project's primary goal is to demonstrate the necessity of early visuospatial memory assessment within the vulnerable population of very preterm children, and to prove the feasibility and efficacy of computerized cognitive training using online software programs. A better global neuropsychological development improvement (visuospatial processing and other far transfer) can be expected with an improvement in learning and decreased behavioral problems. In the long term, these improvements might also reduce those global costs linked to the consequences of extreme prematurity.

TRIAL REGISTRATION

NCT02757794 (registered on 2nd May 2016 at ClinicalTrial.gov).

Placental weight mediates association between prenatal exposure to cooking oil fumes and preterm birth

Background: There are some reports on association between maternal prenatal cooking oil fume (COF) exposure and preterm birth (PTB), but its mechanism remains poorly understood. Therefore, this study aims to assess whether placental weight mediates their associations.Method: We enrolled 619 pregnant women delivering PTB newborns as cases and 1701 delivering full-term appropriate for gestational age newborns as controls. They were inquired with a self-reported questionnaire about prenatal COF exposure, socio-demographics and obstetric characteristics at Women and Children's Hospitals of Shenzhen and Foshan. After controlling for the potential confounders, a series of logistic and linear regressions were conducted to assess associations among COF exposure, placental weight and PTB, and the mediation of placental weight in the association between COF exposure and PTB.Results: Maternal prenatal COF exposure was significantly associated with PTB and the frequency of prenatal COF exposure was negatively associated with placental weight. Compared with mother who never cooked, those cooking occasionally, sometimes or often increased the risk of PTB, and similarly, those cooking between half to an hour was also showed a higher risk of PTB. Typical Chinese cooking methods including stir-frying, pan-frying and deep-frying were also associated with PTB. Different oil types mainly used, including peanut oil, corn oil and animal oil were associated with PTB as well. Mediation analysis illustrated that placental weight partially mediated 13.60% (95% CI = 10.62-33.20%) of the effects on the association between the frequency of maternal prenatal COF exposure and PTB.Conclusion: Maternal cooking during pregnancy and the frequency of prenatal COF exposure might increase the risk of PTB, in which placenta might play mediation role.

The impact of preterm birth on the executive functioning of preschool children: A systematic review

This paper presents a systematic review of the impact of preterm childbirth on the later executive functioning of preschool-aged children. A systematic search for studies published between 2014 and 2019 was performed using the following keywords: executive funct* AND preterm AND child. The methodological quality of the reports was examined using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement. Thirty-two studies were reviewed and scored at least 67% on the methodological quality assessment. In comparison to children born full-term, preschool children born preterm exhibit executive functioning deficits in the dimensions of the global index, inhibitory control, cognitive flexibility, working memory, and planning/executive functioning. These findings are independent of the degree of prematurity at birth. Since executive functioning has many complex components, future studies should assess the dimensions of executive functioning separately in preschool-aged children born preterm, rather than as a single measure.

Executive Functions and Academic Outcomes of Low Birthweight Infants: A Prospective Longitudinal U.S. Cohort

OBJECTIVE

Executive functions such as working memory and cognitive flexibility are key to lifelong learning. Our hypothesis was that children born low birthweight (LBW), defined as weight < 2,500 g, would have lower cognitive outcomes than those born normal weight, and children with poor executive functioning would be at risk for poor academic outcomes.

STUDY DESIGN

We evaluated data from 12,656 children followed prospectively in the Early Childhood Longitudinal Study, Kindergarten Class 2010-2011, assessing outcomes from kindergarten, first grade, and second grade. Multivariable linear and logistic regressions were run evaluating the relationship between birthweight and cognitive outcomes, and the odds of infants with poor executive functioning having poor academic outcomes.

RESULTS

Compared with children with normal birthweight, those born LBW had lower mean z-scores for academic and directly assessed executive functions from kindergarten through second grade. LBW children were at an increased risk of scoring in the bottom 20% of children at all time points: second-grade reading odds ratio (OR) = 1.60 (95% confidence interval [CI:] 1.23-2.09), math OR = 1.49 (95% CI: 1.21-1.84), science OR = 1.41 (95% CI: 1.11-1.81), cognitive flexibility OR = 1.61 (95% CI: 1.27-2.02), and working memory OR = 1.40 (95% CI: 1.10-1.77).

CONCLUSION

LBW infants remain at risk of poor cognitive outcomes in second grade. Early difficulties with executive functioning can increase the risk of a child's academic performance years later.

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.

Investigating the brain structural connectome following working memory training in children born extremely preterm or extremely low birth weight

Children born extremely preterm (EP, <28 weeks' gestation) or extremely low birth weight (ELBW, <1,000 g) are a vulnerable population at high risk of working memory impairments. We aimed to examine changes in the brain structural connectivity networks thought to underlie working memory performance, after completion of a working memory training program (Cogmed) compared with a placebo program in EP/ELBW children. This was a double-blind, placebo-controlled randomized trial (the Improving Memory in a Preterm Randomised Intervention Trial). Children born EP/ELBW received either the Cogmed or placebo program at 7 years of age (n = 91). A subset of children had magnetic resonance imaging of the brain immediately pre- and 2 weeks post-training (Cogmed n = 28; placebo n = 27). T₁ -weighted and diffusion-weighted images were used to perform graph theoretical analysis of structural connectivity networks. Changes from pre-training to post-training in structural connectivity metrics were generally similar between randomized groups. There was little evidence that changes in structural connectivity metrics were related to changes in working memory performance from pre- to post-training. Overall, our results provide little evidence that the Cogmed working memory training program has training-specific effects on structural connectivity networks in EP/ELBW children.

Completeness of Retention Data and Determinants of Attrition in Birth Cohorts of Very Preterm Infants: A Systematic Review

Background: Birth cohorts provided essential knowledge for clinical and public health decision-making. However, little is known about retention and determinants of attrition in these specific longitudinal studies, although characterizing predictors of attrition sets the path to mitigate its occurrence and to promote valid inferences. We systematically reviewed retention in follow-ups of birth cohorts of very preterm or very low birth weight infants and the determinants of attrition. PROSPERO registration number: CRD42017082672. Methods: Publications were identified through PubMed®, Scopus, Web of Science, and Cochrane Library databases from inception to December 2017. Studies were included when reporting at least one of the following: retention at follow-ups, reasons for attrition, or characteristics of non-participants. Quality assessment was conducted using the completeness of the report of participation features in the articles. Non-participant's characteristics were presented using descriptive statistics. Local polynomial regression was used to describe overall retention trends over years of follow-up. Results: We identified 57 eligible publications, reporting on 39 birth cohorts and describing 83 follow-up evaluations. The overall median retention was 87% (p25-p75:75.8-93.6), ranging from 14.6 to 100%. Overall, retention showed a downward trend with increasing child age. Completeness of retention report was considered "enough" in only 36.8% of publications. Considering the 33 (57.9%) publications providing information on participants and non-participants, and although no formal meta-analysis was performed, it was evident that participants lost to follow-up were more often male, had foreign-born, multiparous, and younger mothers, and with a lower socioeconomic status. Conclusion: This systematic review evidenced a lack of detailed data on retention, which may threaten the potential use of evidence derived from cohort studies of very preterm infants for clinical and public health purpose. It supports the requirement for a standardized presentation of retention features responding to current guidelines.

Developmental Trajectories in Very Preterm Born Children Up to 8 Years: A Longitudinal Cohort Study

Aim: Long-term outcome data in preterm children is often limited to cross-sectional measurement of neurodevelopmental impairment (NDI) at the corrected age of 24-36 months. However, impairments may only become overt during childhood or resolve with time, and individual trajectories in outcome over time may vary. The primary aim of this study was to describe NDI in very preterm born children at three subsequent ages of 2, 5, and 8 years of age. As a secondary aim, a longitudinal analysis was performed on the individual longitudinal trajectories in NDI from 2 to 8 years of age. Methods: Single-center prospective cohort study including children born between 1990 and 2011 below 30 weeks' gestation and followed into 2019. The outcome measurement was NDI assessed at 2, 5, and 8 years of age. NDI is a composite score that includes cognitive, neurological, visual, and auditory functions, in which problems were categorized as none, mild, moderate, or severe. Cognitive function measured as total DQ/IQ score was assessed by standardized psychometric tests. Neurological, visual, and auditory functions were assessed by the neonatologist. Results: In total, 921 children were eligible for follow-up, of whom 726 (79%) children were assessed. No NDI was seen in 54, 54, and 62%, mild NDI was seen in 31, 36, and 30%, and moderate-to-severe NDI was seen in 15, 9.2, and 8.6% of the children at 2, 5, and 8 years, respectively. From 2 to 8 years, 63% of the children remained in the same NDI category, 20% of the children improved to a better NDI category, and 17% deteriorated toward a worse NDI category. No differences were found in baseline characteristics of infants that improved or deteriorated. Extreme prematurity, male gender and low parental education were associated with worse NDI status at all time points. Although we observed considerable individual variation over time in NDI status, the course of the trajectories in NDI were not associated with gestation, gender, and parental education. Conclusions: Continued follow-up until school life is essential in order to provide optimal and individually focused referrals and care when needed.

Abnormal placental DNA methylation variation in spontaneous preterm birth

OBJECTIVE

Preterm birth (PTB) has become a major public health concern as the leading cause of neonatal death, but little is understood about its etiology. Children born preterm are also at increased risk of long-term consequences such as neurodevelopmental disorders, adulthood hypertension and diabetes. Recent studies have indicated that DNA methylation may be involved in the occurrence of PTB as well as related adverse outcomes. The latest Infinium EPIC BeadChip extends the coverage of the genome and provides a better tool to help investigate the involvement of DNA methylation in these conditions.

METHODS

We conducted this case-control study in three Women and Children's hospitals in South China, and enrolled 32 spontaneous preterm births and 16 term births. We assessed placental DNA methylation profiling of these participants with the Infinium EPIC BeadChip. We identified PTB and gestational age (GA)-associated CpG sites with limma regression model, and applied seqlm to identify PTB-associated regions. We performed gene ontology analysis to further interpret functional enrichment of the identified differentially methylated genes in PTB.

RESULTS

We identified a total of 8 differentially methylated positions (DMPs) that were significantly associated with PTB (FDR < 0.1) and a total of 15 DMPs that were associated with GA (FDR < 0.1). In the regional analysis, one differentially methylated region in the SLC23A1 gene overlapped with PTB-associated CpG site. The differentially methylated CpG sites in PTB were mapped to the genes involving in biological processes mainly regarding neurodevelopment, regulation of inflammation and metabolism.

CONCLUSION

Our findings suggested that preterm placenta have distinct DNA methylation alterations, and these alteration patterns established at birth provide insight into the long-term consequences of preterm birth.

Relationships between intelligence, executive function and academic achievement in children born very preterm

BACKGROUND

Children born very preterm are at higher risk of adverse neurocognitive and educational outcomes. However, how low intelligence (IQ) and low executive function may each contribute to poorer academic outcomes at school age requires clarification.

AIM

To examine the associations between intelligence, executive function and academic achievement in children born very preterm.

DESIGN/METHODS

This cohort study assessed children born <30 weeks' gestation or <1500 g at age 7 years using the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) for IQ, and the Test of Everyday Attention for Children (TEA-Ch) and Behavior Rating Inventory of Executive Function (BRIEF) for executive function. Academic achievement was rated by teachers against curriculum standards.

RESULTS

Of the 76 children (35 girls, 41 boys, mean age = 7.2 year), 22 (28%) were rated below expected level for reading, 32 (42%) for writing and 38 (50%) for mathematics. After adjustment for sex and socioeconomic status, low IQ (OR's 9.0-12.3) and most low executive function measures (OR's 4.1-9.3) were associated with below-expected achievement. After further adjustment for IQ, low cognitive flexibility (OR = 9.3, 95% CI = 1.2-71.5) and teacher ratings of executive function (OR = 5.3, 95% CI = 1.4-20.2) were associated with below-expected achievement. Mediation analysis showed IQ had indirect effects on writing (b = 1.5, 95% CI = 0.6-3.1) via attentional control; and on reading (b = 1.0, 95% CI = 0.2-3.2) and writing (b = 0.8, 95% CI = 0.1-2.5) via cognitive flexibility.

CONCLUSIONS

Both low IQ and low executive function are associated with below-expected teacher-rated academic achievement in children born very preterm. IQ may influence academic achievement in part through executive function.

Gestational Age is Dimensionally Associated with Structural Brain Network Abnormalities Across Development

Prematurity is associated with diverse developmental abnormalities, yet few studies relate cognitive and neurostructural deficits to a dimensional measure of prematurity. Leveraging a large sample of children, adolescents, and young adults (age 8-22 years) studied as part of the Philadelphia Neurodevelopmental Cohort, we examined how variation in gestational age impacted cognition and brain structure later in development. Participants included 72 preterm youth born before 37 weeks' gestation and 206 youth who were born at term (37 weeks or later). Using a previously-validated factor analysis, cognitive performance was assessed in three domains: (1) executive function and complex reasoning, (2) social cognition, and (3) episodic memory. All participants completed T1-weighted neuroimaging at 3 T to measure brain volume. Structural covariance networks were delineated using non-negative matrix factorization, an advanced multivariate analysis technique. Lower gestational age was associated with both deficits in executive function and reduced volume within 11 of 26 structural covariance networks, which included orbitofrontal, temporal, and parietal cortices as well as subcortical regions including the hippocampus. Notably, the relationship between lower gestational age and executive dysfunction was accounted for in part by structural network deficits. Together, these findings emphasize the durable impact of prematurity on cognition and brain structure, which persists across development.

DHA supplementation in infants born preterm and the effect on attention at 18 months' corrected age: follow-up of a subset of the N3RO randomised controlled trial

Infants born preterm miss out on the peak period of in utero DHA accretion to the brain during the last trimester of pregnancy which is hypothesised to contribute to the increased prevalence of neurodevelopmental deficits in this population. This study aimed to determine whether DHA supplementation in infants born preterm improves attention at 18 months' corrected age. This is a follow-up of a subset of infants who participated in the N3RO randomised controlled trial. Infants were randomised to receive an enteral emulsion of high-dose DHA (60 mg/kg per d) or no DHA (soya oil - control) from within the first days of birth until 36 weeks' post-menstrual age. The assessment of attention involved three tasks requiring the child to maintain attention on toy/s in either the presence or absence of competition or a distractor. The primary outcome was the child's latency of distractibility when attention was focused on a toy. The primary outcome was available for seventy-three of the 120 infants that were eligible to participate. There was no evidence of a difference between groups in the latency of distractibility (adjusted mean difference: 0·08 s, 95 % CI -0·81, 0·97; P = 0·86). Enteral DHA supplementation did not result in improved attention in infants born preterm at 18 months' corrected age.

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

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

Neuropsychological Outcomes at 19 Years of Age Following Extremely Preterm Birth

BACKGROUND AND OBJECTIVES

Children born extremely preterm (EP) (<26 weeks' gestation) have lower cognitive scores and an increased rate of cognitive impairment compared with their term-born peers. However, the neuropsychological presentation of these EP individuals in adulthood has not been described. The aim of this study was to examine neuropsychological outcomes in early adulthood after EP birth in the 1995 EPICure cohort and to investigate if the rate of intellectual impairment changed longitudinally.

METHODS

A total of 127 young adults born EP and 64 term-born controls had a neuropsychological assessment at 19 years of age examining general cognitive abilities (IQ), visuomotor abilities, prospective memory, and aspects of executive functions and language.

RESULTS

Adults born EP scored significantly lower than term-born controls across all neuropsychological tests with effect sizes (Cohen's d) of 0.7 to 1.2. Sixty percent of adults born EP had impairment in at least 1 neuropsychological domain; deficits in general cognitive functioning and visuomotor abilities were most frequent. The proportion of EP participants with an intellectual impairment (IQ <70) increased by 6.7% between 11 and 19 years of age (P = .02). Visuospatial functioning in childhood predicted visuomotor functioning at 19 years.

CONCLUSIONS

Adults born EP continue to perform lower than their term-born peers in general cognitive abilities as well as across a range of neuropsychological functions, indicating that these young adults do not show improvement overtime. The prevalence of intellectual impairment increased from 11 years into adulthood.

Relative contributions of prenatal complications, perinatal characteristics, neonatal morbidities and socio-economic conditions of preterm infants on the occurrence of developmental disorders up to 7 years of age

BACKGROUND

To investigate the relative contributions of prenatal complications, perinatal characteristics, neonatal morbidities and socio-economic conditions on the occurrence of motor, sensory, cognitive, language and psychological disorders in a large longitudinal preterm infant population during the first 7 years after birth.

METHODS

The study population comprised 4122 infants born at <35 weeks of gestation who were followed for an average of 74.0 months after birth. Developmental disorders, including motor, sensory, cognitive, language and psychological, were assessed at each follow-up visit from 18 months to 7 years of age. The investigated determinants included prenatal complications (prolonged rupture of membranes >24 hours, intrauterine growth restriction, preterm labour and maternal hypertension), perinatal characteristics (gender, multiple pregnancies, gestational age, birth weight, APGAR score and intubation or ventilation in the delivery room), neonatal complications (low weight gain during hospitalization, respiratory assistance, severe neurological anomalies, nosocomial infections) and socio-economic characteristics (socio-economic level, parental separation, urbanicity). Based on hazard ratios determined using a propensity score matching approach, population-attributable fractions (PAF) were calculated for each of the four types of determinants and for each developmental disorder.

RESULTS

The percentages of motor, sensory, cognitive, language and psychological disorders were 17.0, 13.4, 29.1, 25.9 and 26.1%, respectively. The PAF for the perinatal characteristics were the highest and they were similar for the different developmental disorders considered (around 60%). For the neonatal and socio-economic determinants, the PAF varied according to the disorder, with contributions of up to 17% for motor and 27% for language disorders, respectively. Finally, prenatal complications had the lowest contributions (between 6 and 13%).

CONCLUSIONS

This study illustrates the heterogeneity of risk factors on the risk of developmental disorder in preterm infants. These results suggest the importance of considering both medical and psycho-social follow-ups of preterm infants and their families.

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.

The Inter-Relationships of Extremely Low Birth Weight, Asthma, and Behavior: A Study of Common Cause, Mediation, and Moderation

BACKGROUND

Extremely low birth weight (ELBW; <1000 g) infants are at risk for both asthma and problems like inattention, hyperactivity, anxiety, and depression. Asthma predicts behavioral and emotional problems in term-born children. The nature of these associations is poorly understood. We tested 3 models of association: independent risk, mediation, and effect modification to explore interplay among birth weight, asthma, and behavioral and emotional problems.

METHODS

We used data from a prospective cohort of ELBW infants born 1992 to 1995. Exposure was ELBW; primary outcomes were parent-reported diagnosis of asthma and symptoms of inattention, hyperactivity, anxiety, and depression at age 8 years. Covariates included child sex and maternal socioeconomic status.

RESULTS

There were 139 ELBW and 101 normal BW (>2500 g) children followed to 8 years. ELBW children were more likely to have asthma (35.7% vs 14.4%, P < .05). Inattention, hyperactivity, depression, and anxiety scores were higher among ELBW children and children with asthma. ELBW was a common cause of asthma and anxiety. There was no evidence of mediation or effect modification by asthma on the effect of ELBW on behavior and emotion symptoms.

CONCLUSION

Asthma does not underlie or amplify the effect of ELBW on behavioral and emotional problems at school age, suggesting that increased risk for respiratory morbidity and neurodevelopment represent largely independent consequences of developmental vulnerability related to ELBW. Noting the impact of chronic illnesses on neurodevelopment in other populations, data focused on symptom trajectories over time in a larger cohort may be necessary to shed further light onto this question.

A Comparison of the effects of preterm birth and institutional deprivation on child temperament

Both preterm birth and early institutional deprivation are associated with neurodevelopmental impairment-with both shared and distinctive features. To explore shared underlying mechanisms, this study directly compared the effects of these putative risk factors on temperament profiles in six-year-olds: Children born very preterm (<32 weeks gestation) or at very low birthweight (<1500 g) from the Bavarian Longitudinal Study (n = 299); and children who experienced >6 months of deprivation in Romanian institutions from the English and Romanian Adoptees Study (n = 101). The former were compared with 311 healthy term born controls and the latter with 52 nondeprived adoptees. At 6 years, temperament was assessed via parent reports across 5 dimensions: effortful control, activity, shyness, emotionality, and sociability. Very preterm/very low birthweight and postinstitutionalized children showed similarly aberrant profiles in terms of lower effortful control, preterm = -0.50, 95% CI [-0.67, -0.33]; postinstitutionalized = -0.48, 95% CI [-0.82, -0.14], compared with their respective controls. Additionally, postinstitutionalized children showed higher activity, whereas very preterm/very low birthweight children showed lower shyness. Preterm birth and early institutionalization are similarly associated with poorer effortful control, which might contribute to long-term vulnerability. More research is needed to examine temperamental processes as common mediators of negative long-term outcomes following early adversity.

Working memory training and brain structure and function in extremely preterm or extremely low birth weight children

This study in children born extremely preterm (EP; <28 weeks' gestational age) or extremely low birth weight (ELBW; <1,000 g) investigated whether adaptive working memory training using Cogmed® is associated with structural and/or functional brain changes compared with a placebo program. Ninety-one EP/ELBW children were recruited at a mean (standard deviation) age of 7.8 (0.4) years. Children were randomly allocated to Cogmed or placebo (45-min sessions, 5 days a week over 5-7 weeks). A subset had usable magnetic resonance imaging (MRI) data pretraining and 2 weeks posttraining (structural, n = 48; diffusion, n = 43; task-based functional, n = 18). Statistical analyses examined whether cortical morphometry, white matter microstructure and blood oxygenation level-dependent (BOLD) signal during an n-back working memory task changed from pretraining to posttraining in the Cogmed and placebo groups separately. Interaction analyses between time point and group were then performed. There was a significant increase in neurite density in several white matter regions from pretraining to posttraining in both the Cogmed and placebo groups. BOLD signal in the posterior cingulate and precuneus cortices during the n-back task increased from pretraining to posttraining in the Cogmed but not placebo group. Evidence for group-by-time interactions for the MRI measures was weak, suggesting that brain changes generally did not differ between Cogmed and placebo groups. Overall, while some structural and functional MRI changes between the pretraining and posttraining period in EP/ELBW children were observed, there was little evidence of training-induced neuroplasticity, with changes generally identified in both groups. Trial registration Australian New Zealand Clinical Trials Registry, anzctr.org.au; ACTRN12612000124831.

Spectral slowing is associated with working memory performance in children born very preterm

Children born very preterm (VPT) often demonstrate selective difficulties in working memory (WM), which may underlie academic difficulties observed in this population. Despite this, few studies have investigated the functional networks underlying WM in young children born VPT, a period when cognitive deficits become apparent. Using magnetoencephalography, we examined the networks underlying the maintenance of visual information in 6-year-old VPT (n = 15) and full-term (FT; n = 20) children. Although task performance was similar, VPT children engaged different oscillatory mechanisms during WM maintenance. Within the FT group, we observed higher mean whole-brain connectivity in the alpha-band during the retention (i.e. maintenance) interval associated with correct compared to incorrect responses. VPT children showed reduced whole-brain alpha synchrony, and a different network organization with fewer connections. In the theta-band, VPT children demonstrated a slight increase in whole-brain connectivity during WM maintenance, and engaged similar network hubs as FT children in the alpha-band, including the left dorsolateral prefrontal cortex and superior temporal gyrus. These findings suggest that VPT children rely on the theta-band to support similar task performance. Altered oscillatory mechanisms may reflect a less mature pattern of functional recruitment underlying WM in VPT children, which may affect the processing in complex ecological situations.

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.

Executive Function Profiles at Home and at School in 11-Year-Old Very Low Birth Weight or Very Low Gestational Age Children

OBJECTIVE

Executive function (EF) problems of children born at very low birth weight (VLBW; ≤1500 g) or very low gestational age (VLGA; <32 gestational weeks) may present differently at school compared to the home environment. Ecological assessment of EF including parent- and teacher-rated profiles and associated risk factors of 11-year-old children born at VLBW or VLGA was evaluated.

METHODS

A total of 125 VLBW or VLGA children and 132 controls were assessed using the Behavior Rating Inventory of EF, which includes 8 subscales that form the Behavioral Regulation and Metacognition Indexes. For VLBW or VLGA children, full-scale intelligence quotient (IQ) was assessed using the Wechsler Intelligence scale for Children, Fourth Edition. Neonatal data were collected systematically.

RESULTS

VLBW or VLGA children with full-scale IQ ≥ 70 had clinically significant problems in the Working Memory subscale at school. Although they had clinically significant problems at home in the Behavioral Regulation Index, the difference disappeared when adjusted for paternal education. Lower gestational age, lower birth weight z-score, surgical necrotizing enterocolitis, low paternal and maternal education, and lower full-scale IQ were identified to be risk factors for higher scores in ecological assessment of EF.

CONCLUSION

VLBW or VLGA children in this cohort exhibit fewer EF problems in ecological assessment of EF compared to previous literature. EF problems of this study population vary by home and school setting and are emphasized in working memory at school. Screening for EF problems in school environment is recommended to target the support.

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.

The Influence of Early Nutrition on Brain Growth and Neurodevelopment in Extremely Preterm Babies: A Narrative Review

Extremely preterm babies are at increased risk of less than optimal neurodevelopment compared with their term-born counterparts. Optimising nutrition is a promising avenue to mitigate the adverse neurodevelopmental consequences of preterm birth. In this narrative review, we summarize current knowledge on how nutrition, and in particular, protein intake, affects neurodevelopment in extremely preterm babies. Observational studies consistently report that higher intravenous and enteral protein intakes are associated with improved growth and possibly neurodevelopment, but differences in methodologies and combinations of intravenous and enteral nutrition strategies make it difficult to determine the effects of each intervention. Unfortunately, there are few randomized controlled trials of nutrition in this population conducted to determine neurodevelopmental outcomes. Substantial variation in reporting of trials, both of nutritional intakes and of outcomes, limits conclusions from meta-analyses. Future studies to determine the effects of nutritional intakes in extremely preterm babies need to be adequately powered to assess neurodevelopmental outcomes separately in boys and girls, and designed to address the many potential confounders which may have clouded research findings to date. The development of minimal reporting sets and core outcome sets for nutrition research will aid future meta-analyses.

The World Health Organization ACTION-I (Antenatal CorTicosteroids for Improving Outcomes in preterm Newborns) Trial: a multi-country, multi-centre, two-arm, parallel, double-blind, placebo-controlled, individually randomized trial of antenatal corticosteroids for women at risk of imminent birth in the early preterm period in hospitals in low-resource countries

Background

Antenatal corticosteroids (ACS) have long been regarded as a cornerstone intervention in mitigating the adverse effects of a preterm birth. However, the safety and efficacy of ACS in hospitals in low-resource countries has not been established in an efficacy trial despite their widespread use. Findings of a large cluster-randomized trial in six low- and middle-income countries showed that efforts to scale up ACS use in low-resource settings can lead to harm. There is equipoise regarding the benefits and harms of ACS use in hospitals in low-resource countries. This randomized controlled trial aims to determine whether ACS are safe and efficacious when given to women at risk of imminent birth in the early preterm period, in hospitals in low-resource countries.

Methods/design

The trial design is a parallel, two-arm, double-blind, individually randomized, placebo-controlled trial of ACS (dexamethasone) for women at risk of imminent preterm birth. The trial will recruit 6018 women in participating hospitals across five low-resource countries (Bangladesh, India, Kenya, Nigeria and Pakistan). The primary objectives are to compare the efficacy of dexamethasone with placebo on survival of the baby and maternal infectious morbidity. The primary outcomes are: 1) neonatal death (to 28 completed days of life); 2) any baby death (any stillbirth postrandomization or neonatal death); and 3) a composite outcome to assess possible maternal bacterial infections. The trial will recruit eligible, consenting pregnant women from 26 weeks 0 days to 33 weeks 6 days gestation with confirmed live fetuses, in whom birth is planned or expected within 48 h. The intervention comprises a regimen of intramuscular dexamethasone sodium phosphate. The comparison is an identical placebo regimen (normal saline). A total of 6018 women will be recruited to detect a reduction of 15% or more in neonatal deaths in a two-sided 5% significance test with 90% power (including 10% loss to follow-up).

Discussion

Findings of this trial will guide clinicians, programme managers and policymakers on the safety and efficacy of ACS in hospitals in low-resource countries. The trial findings will inform updating of the World Health Organization’s global recommendations on ACS use.

Trial registration

ACTRN12617000476336. Registered on 31 March 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3488-z) contains supplementary material, which is available to authorized users.

Neurocognitive processes underlying academic difficulties in very preterm born adolescents

Very preterm birth is associated with academic difficulties, but the underlying neurocognitive mechanisms of these difficulties remain largely unclear. The present study aimed to assess the role of working memory (WM), attentional processes, and processing speed in academic difficulties of very preterm born adolescents at 13 years. Participants included 55 very preterm and 61 full-term adolescents. Academic performance, visuospatial WM, alerting, orienting, executive attention, sustained attention, and processing speed (simple and choice reaction time [RT]) were compared between groups. Mediation analyses with multiple, parallel mediators were performed to examine whether these functions mediate the relation between very preterm birth and academic performance. Very preterm born adolescents showed poorer reading comprehension, arithmetic, visuospatial WM, alerting, sustained attention, and choice RT than full-term controls. The relationship between very preterm birth and arithmetic was mediated by visuospatial WM, sustained attention, and choice RT. The relationship between very preterm birth and reading comprehension was mediated by visuospatial WM and choice RT. The findings indicate that very preterm birth affects arithmetic and reading comprehension through its negative effect on visuospatial WM, sustained attention, and processing speed. These neurocognitive processes may identify very preterm born children at risk for academic difficulties and could serve as targets for interventions.

Associations between parenting behavior and executive function among preschool-aged children born very preterm

The objective of the current study was to determine whether three domains of observed parenting behavior were associated with executive function in preschool-aged children born very preterm (<30 completed weeks' gestation). Executive function of 41 preschool-aged (3.5 to 4.5 years) children was assessed using a standardized protocol (gift delay) and by parent-report (Behavior Rating Inventory of Executive Function-Preschool, BRIEF-P). Observational protocols were used to determine parental sensitivity, harsh intrusiveness, and dyadic mutuality in a semi-structured play task. Parental sensitivity and mutuality were rated as higher, and harsh intrusiveness was rated as lower for children high in executive function on the gift delay task. Similarly, correlations between the three parenting scales and the BRIEF-P Global Executive Composite t-score were in the expected direction though not always statistically significant. Findings suggest that very preterm children who experienced sensitive parenting and were rated as having greater mutuality in their interactions with their caregivers scored higher on executive function tasks. These findings add to the growing literature on the key role that sensitive parenting and mutually responsive, harmonious interactions between caregivers and children may play in the development of executive function in very preterm children.

Childhood Motor Coordination and Adult Affective Experience Among Extremely Low Birth Weight Survivors

Poor motor coordination in childhood has been associated in adulthood with more negative affect, less positive affect, and an increased risk of psychopathology. While survivors of extremely low birth weight (ELBW; < 1,000 grams) are more likely to manifest poor motor coordination than people born at normal birth weight (NBW; > 2,500 g), they have had better mental health outcomes than those with NBW who have motor difficulties. How emotion is experienced is an important risk factor for mental illness; yet, little is known about the affective experience of survivors of ELBW who also have poor motor coordination. In this longitudinal study, we examined interactions between birth weight status and childhood motor coordination on affective experience among 88 ELBW and 89 NBW participants. We first assessed childhood motor coordination at eight years of age, using the Bruininks-Oseretsky Test of Motor Proficiency, and we later gathered self-report data regarding affective style, using the Positive and Negative Affect Scedule and the Affective Styles Questionnaire, when these participants were 30-35 years of age. We found a statistically significant interaction between motor coordination and birth weight status. As motor coordination worsened among ELBW survivors, positive affect increased, while we observed the opposite trend in NBW participants (p < 0.05). There was no interaction for negative affect. Positive affect may contribute to previous findings of better relative adult mental health among ELBW survivors with poor childhood motor coordination. Strategies aimed at optimizing positive affect may be fruitful for optimizing mental health outcomes among preterm survivors and others with reduced motor proficiency.