Executive function deficits mediate the association between very preterm birth and behavioral problems at school-age

Early High-Dose Erythropoietin and Cognitive Functions of School-Aged Children Born Very Preterm

Importance

Children born very preterm are at risk for long-term neurodevelopmental sequelae. Prophylactic high-dose recombinant human erythropoietin (rhEpo) shortly after birth has not been shown to improve cognitive, motor, and behavioral development at 2 and 5 years.

Objective

To investigate whether early high-dose rhEpo is associated with better executive functions and processing speed-late-maturing cognitive functions-in school-aged children born very preterm.

Design, Setting, and Participants

This single-center cohort study was a prospective, observational follow-up study of a multicenter neonatal clinical trial; 365 children born very preterm (mean gestational age, 29.3 weeks [range, 26.0-31.9 weeks]) who had been enrolled in the Swiss EPO Neuroprotection Trial at birth between 2005 and 2012, and who were included in the primary outcome analyses at 2 years, were eligible to be recruited for the EpoKids study between 2017 and 2021 when they were at school age. Term-born children were additionally recruited and included in a control group. Data were analyzed between May and September 2022.

Exposure

Administration of rhEpo (3000 IU/kg) or placebo (saline, 0.9%) intravenously 3 times within the first 2 days of life as part of the Swiss EPO Neuroprotection Trial.

Main Outcome and Measures

A comprehensive neuropsychological test battery assessed executive functions and processing speed, and parents reported on their child's executive functions in everyday life to test the hypothesis that early high-dose rhEpo administration is associated with better cognitive outcomes at school age.

Results

In the EpoKids study, 214 children born very preterm (58.6% of 365 children in eligible cohort) were assessed at a mean age of 10.4 years (range, 6.9-13.4 years); 117 (54.7%) were boys. There was no evidence that the 117 children who had received rhEpo differed from the 97 children who had received placebo in any of the 15 executive function and processing speed tests, nor in parent-rated executive functions (estimates ranged from -0.138 to 0.084, all 95% CIs included 0). Irrespective of rhEpo or placebo allocation, children born very preterm scored lower on 11 of 15 executive function and processing speed tests than term-born peers (estimates ranged from 0.112 to 0.255, 95% CIs did not include 0).

Conclusion and Relevance

This study found no evidence for a positive association between prophylactic early high-dose rhEpo administration and long-term neurodevelopmental outcomes after very preterm birth. These results suggest that a comprehensive approach, including pharmacological and nonpharmacological prevention and intervention strategies, is needed to support these children's neurodevelopmental outcome.

Cerebral perfusion differences are linked to executive function performance in very preterm-born children and adolescents

Children and adolescents born very preterm are at risk of cognitive impairment, particularly affecting executive functions. To date, the neural correlates of these cognitive differences are not yet fully understood, although converging evidence points to a pattern of structural and functional brain alterations, including reduced brain volumes, altered connectivity, and altered brain activation patterns. In very preterm neonates, alterations in brain perfusion have also been reported, but the extent to which these perfusion alterations persist into later childhood is not yet known. This study evaluated global and regional brain perfusion, measured with arterial spin labelling (ASL) MRI, in 26 very preterm children and adolescents and 34 term-born peers. Perfusion was compared between groups and relative to executive function (EF) scores, derived from an extensive EF battery assessing working memory, cognitive flexibility, and planning. Very preterm children and adolescents showed regions of altered perfusion, some of which were also related to EF scores. Most of these regions were located in the right hemisphere and included regions like the thalamus and hippocampus, which are known to play a role in executive functioning and can be affected by prematurity. In addition, perfusion decreased with age during adolescence and showed a significant interaction between birth status and sex, such that very preterm girls showed lower perfusion than term-born girls, but this trend was not seen in boys. Taken together, our results indicate a regionally altered perfusion in very preterm children and adolescents, with age and sex related changes during adolescence.

Neurobehavioral symptoms in children born extremely preterm: A Swedish National Study

AIM

To determine the prevalence of neurobehavioral symptoms at 6.5 years in children born extremely preterm (EPT, <27 weeks' gestation).

METHODS

Population-based cohort study of infants born EPT in Sweden from 2004 to 2007. Of 486 survivors 375 were assessed and compared with 369 matched term-born controls. EPT children free from neurosensory and intellectual disabilities (neurodevelopmental disabilities [NDD]-free, n = 236) were compared separately. Standardised questionnaires were used to assess parental ratings of hyperactivity and attention, emotional, peer-relation, conduct and social problems; and deficits in perception, language and memory.

RESULTS

EPT children had more reported problems in all assessed neurobehavioral domains than controls, with more than three times greater odds for most outcomes. Except for conduct problems, increased problems were identified also in NDD-free children. The odds of having neurobehavioral problems in ≥3 co-occurring domains were five (whole EPT group) and three (NDD-free group) times higher than in controls.

CONCLUSION

EPT children with or without NDD have more neurobehavioral problems in multiple domains than term peers. Ongoing assessments of behaviour until school age or beyond should recognise early symptoms of attention, everyday social problems, perceptual, emotional or language difficulties.

Executive function and behaviour problems in school-age children born at risk of neonatal hypoglycaemia

AIM

To examine the relationship between neonatal hypoglycaemia and specific areas of executive function and behaviour in mid-childhood.

METHOD

Participants in a prospective cohort study of infants born late preterm or at term at risk of neonatal hypoglycaemia were assessed at 9 to 10 years. We assessed executive function using performance-based (Cambridge Neuropsychological Tests Automated Battery) and questionnaire-based (Behavior Rating Inventory of Executive Function) measures and behaviour problems with the Strengths and Difficulties Questionnaire. Data are reported as adjusted odds ratio (aOR) with 95% confidence intervals, and standardized regression coefficients.

RESULTS

We assessed 480 (230 females, 250 males; mean age 9 years 5 months [SD 4 months, range 8 years 8 months-11 years 0 months]) of 587 eligible children (82%). There were no differences in performance-based executive function between children who did and did not experience neonatal hypoglycaemia (blood glucose <2.6 mmoL/L). However, children who experienced hypoglycaemia, especially if severe or recurrent, were at greater risk of parent-reported metacognition difficulties (aOR 2.37-3.71), parent-reported peer (aOR 1.62-1.89) and teacher-reported conduct (aOR 2.14 for severe hypoglycaemia) problems. Both performance- and questionnaire-based executive functions were associated with behaviour problems.

INTERPRETATION

Neonatal hypoglycaemia may be associated with difficulties in specific aspects of parent-reported executive functions and behaviour problems in mid-childhood.

Neurodevelopmental outcomes of very low birth weight preterms in preschool childhood: a prospective cohort study

BACKGROUND

Preterm birth is a risk factor for a child's neurological development. Preterm children have unusual neurodevelopmental profiles with executive, visual-motor functions, fine and gross motor skills, language and behavior that affect learning. In this study, we analyzed the neurodevelopmental outcomes of a cohort of very low birth weight infants admitted to the Treviso Neonatal Intensive Care Unit (NICU) between 2014 and 2016 and followed up to preschool childhood.

METHOD

This is a prospective cohort study. Infants were followed at birth and after NICU discharge at two- and four-year follow-ups. The two-year assessment was conducted with Bayley III, and at four years with the Wechsler Preschool and Primary Scale of Intelligence - III scales and Movement Assessment Battery for Children - 2.

RESULTS

The cohort consisted of 207 subjects with a mean gestational age of 28.9 weeks, and a mean birth weight of 1097.2 g. At two years of age, children without disabilities were 90 (59.6%), those with minor disabilities 47 (31.1%), and those with major disabilities 14 (9.3%); at four years, 58.4% of children without previous disabilities, presented problems with verbal tests and manual dexterity: aiming, grasping and balance at movement assessment. There was significant alteration in processing speed (p < 0.001). Furthermore, there was a strong correlation between processing speed and manual dexterity (p < 0.001) and between processing speed and aiming and grasping (p = 0.0059).

CONCLUSIONS

We found that more than half the children free of disability at two years, at four years had deficit often involving the oculo-motor coordination and processing speed. These motor profile alterations limit the expression of cognitive abilities and the achievement of expected school performance, thus resulting in behavioral disorders, typical of preterm children. Early professional follow-up could improve the expected educational outcomes.

Person-centred Approaches to Psychopathology in the ABCD Study: Phenotypes and Neurocognitive Correlates

Issues with classifying psychopathology using narrow diagnostic categories have prompted calls for the use of dimensional approaches. Yet questions remain about how closely dimensional approaches reflect the way symptoms cluster in individuals, whether known risk factors (e.g. preterm birth) produce distinct symptom phenotypes, and whether profiles reflecting symptom clusters are associated with neurocognitive factors. To identify distinct profiles of psychopathology, latent class analysis was applied to the syndrome scales of the parent-reported Child Behaviour Checklist for 11,381 9- and 10- year-olds from the Adolescent Brain Cognitive Development study. Four classes were identified, reflecting different profiles, to which children were assigned probabilistically; Class 1 (88.6%) reflected optimal functioning; Class 2 (7.1%), predominantly internalising; Class 3 (2.4%), predominantly externalising; and Class 4 (1.9%), universal difficulties. To investigate the presence of a possible preterm behavioural phenotype, the proportion of participants allocated to each class was cross-tabulated with gestational age category. No profile was specific to preterm birth. Finally, to assess the neurocognitive factors associated with class membership, elastic net regressions were conducted revealing a relatively distinct set of neurocognitive factors associated with each class. Findings support the use of large datasets to identify psychopathological profiles, explore phenotypes, and identify associated neurocognitive factors.

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.

Neuropsychological abilities underpinning academic attainment in children born extremely preterm

Children born extremely preterm (EP) have poorer academic attainment than their term-born peers. There is a need to identify the specific cognitive mechanisms that are associated with poor academic attainment in preterm populations to inform the development of intervention strategies. A parallel mediation analysis was conducted with cross-sectional data from 152 EP children (< 27 weeks of gestation) and 120 term-born controls who were assessed at age 11. Mathematics and reading attainment was assessed using the Wechsler Individual Achievement Test 2nd Edition. Controlling for sex and socio-economic status we evaluated the following mediators: verbal working memory, visuospatial working memory, verbal processing speed, attention, and visuospatial processing. These were assessed using subtests from the standardized NEPSY-II test and Wechsler Intelligence Scale for Children-5th Edition. Verbal working memory, visuospatial working memory, visuospatial processing and verbal processing speed, but not attention, were significant independent mediators between EP birth and attainment in reading. No direct relationship between EP birth and reading attainment remained in the mediated model. All five neuropsychological variables mediated the relationship between EP birth and attainment in mathematics, but a direct effect of EP birth on mathematics remained in the mediated model. Together, all five neuropsychological abilities indirectly explained 44% of the variance in reading and 52% of the variance in mathematics. Visuospatial processing was the strongest mediator of both mathematics and reading. Components of executive function, especially visuospatial processing, are important predictors of academic attainment. Interventions to improve visuospatial skills could be trialed in EP populations.

Relationship between Neonatal MRI Findings and Emotional/Behavioral Evaluation in Early Childhood for Extremely Low-Birth-Weight Infants

The aim of this study is to investigate whether it is possible to detect future behavioral and emotional problems in extremely low-birth-weight infants by evaluating the neonatal head magnetic resonance imaging (MRI) using a scoring system. This study included 62 extremely low-birth-weight infants born between April 2015 and March 2017 and those who had undergone MRI at 36 to 42 weeks of gestation. These subjects were administered with the Strength and Difficulties Questionnaire (SDQ) at age 4–5, and the patients who responded to the questionnaire were included in the study. A positive correlation was observed between the Global Brain Abnormality Score and Total Difficulties Score of the SDQ (r = 0.26, p = 0.038). However, no significant difference was observed between the median Global Brain Abnormality Score of the normal and borderline-range group and the Total Difficulties Score of the clinical-range group (p = 0.51). This study demonstrated the relationship between the MRI findings in the newborn period and the emotional and behavioral problems in early childhood, but it is not clinically useful as a predictive marker.

A Validated WISC-V Short-Form to Estimate Intellectual Functioning in Very Preterm Children at Early School Age

Very preterm children (gestational age < 32 weeks) frequently show neurodevelopmental difficulties (Inattention/dysexecutiveness) throughout their life-stages. A scarcity of resources, along with this population’s cognitive vulnerability, makes the neuropsychological evaluation of these children both complicated and time-consuming. This study aimed to develop a specific and valid Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V) short-form to estimate intellectual functioning in this population. Eighty-four very preterm children (39 female; mean age = 6.50; SD: 0.06) were assessed with the WISC-V. Short-forms were developed following two independent strategies: a) multiple linear regressions for each index; b) correlational analyses between scores on all administered subtests and Full-Scale IQ. Validity of short-forms was analyzed. A short-form (Vocabulary, Matrix Reasoning, Picture Span, and Symbol Search) that satisfied 2/3 validation criteria was proposed. This validated short-form could facilitate the identification of cognitive difficulties in very preterm children, so that they could benefit from early care and support services, avoiding long assessment procedures.

Neuropsychological Development and New Criteria for Extrauterine Growth Restriction in Very Low-Birth-Weight Children

Background: Controversy between short-term neonatal growth of very low birth-weight preterm (VLBW) and neurodevelopment may be affected by criteria changes of extrauterine growth restriction (EUGR). Objective: to determine if new EUGR criteria imply modifications in the relationship between old criteria and results of neuropsychological tests in preterm children. Patients and methods: 87 VLBW at 5–7 years of age were studied. Neuropsychological assessment included RIST test (Reynolds Intellectual Sctreening Test) and NEPSY-II (NE neuro, PSY psycolgy assessment) tests. The relationships between these tests and the different growth parameters were analyzed. Results: RIST index was correlated with z-score Fenton’s weight (p = 0.004) and length (p = 0.003) and with z-score IGW-21’s (INTERGRWTH-21 Project) weight (p = 0.004) and length (p = 0.003) at neonatal discharge, but not with z-score difference between birth and neonatal discharge in weight, length, and HC for both. We did not find a statistically significant correlation between Fenton or IGW-21 z-scores and scalar data of NEPSY-II subtasks. Conclusion: In our series, neonatal growth influence on neuropsychological tests at the beginning of primary school does not seem robust, except for RIST test. New EUGR criteria do not improve the predictive ability of the old ones.

The contributions of intelligence and executive function to behaviour problems in school-age children born very preterm

AIM

To examine the contributions of specific neurocognitive skills to behaviour problems in children born very preterm.

METHODS

We assessed children born <30 weeks' gestation or <1500 g at age 7 years using subtests of the Wechsler Intelligence Scale for Children Fourth Edition, performance and questionnaire-based measures of executive function, and Child Behavior Checklist and Teacher Rating Form. We evaluated the contributions of IQ and executive function to behaviour problems and the moderating effect of sex using multiple regression.

RESULTS

The 129 children (mean age = 7.2 years) had lower IQ, inferior executive function and increased internalising problems compared with normative samples. Verbal comprehension skills and working memory were associated with total, internalising and externalising problems at school. Performance-based and questionnaire-based executive function were associated with total and externalising behaviour problems both at home and school. Sex moderated the relationships between information processing and parent-reported total problems, and between teacher-rated executive function and total problems.

CONCLUSION

Both IQ and executive function are related to behaviour problems in children born very preterm, but the relationships are different in boys and girls. Executive function may be a useful target for intervention.