Executive functions in school-age children born very prematurely

BACKGROUND: School-age preterm children are at risk for cognitive difficulties including Executive Dysfunction and low average IQ. AIM: The aim of this study was to determine the performance of very preterm, school-age children on three components of Executive Function (EF), two components of Executive Attention and a measure of IQ. STUDY DESIGN: Cross-sectional, independent samples comparison. METHODS: A UK sample of 40 very preterm (<32 weeks gestational age, Mean 28.43, SD 2.41) children and 41 term born control children aged between 6 and 12 years (mean ages 8 years 5 months in both groups) was assessed on IQ, EF (inhibition, working memory and set shifting) and attention (sustained and selective). Between group comparisons were made using multivariate analysis of variance and covariance. RESULTS: Multivariate analyses indicated that preterm children scored significantly lower than their term born peers across Executive Function and executive attention tasks. As expected, the preterm group achieved IQ scores at the low end of the average range. Univariate analyses indicated some difficulties with shifting and inhibition components of EF, although covariate analysis revealed that only shifting was independent of IQ. CONCLUSIONS: Preterm children showed mild executive function and executive attention difficulties in the context of average IQ scores. The findings highlight the benefit of using multivariate assessments of executive skills rather than general intellectual outcome alone, to obtain a better distinction of the specific cognitive weaknesses associated with preterm birth.     

Neurodevelopmental follow-up after preterm birth: follow up after two years

Marked differences are seen in neurological and health status, intellectual functioning, school performance and behaviour between children born prematurely and those born at term. Assessment in later childhood has identified more subtle problems than the severe disability or sensory deficits readily identifiable at two years. These problems include learning disabilities, specific neuropsychological deficits in executive function, difficulties in visual-motor integration and perception, selective language impairment, motor coordination disorders, behaviour problems, attention deficit hyperactivity disorder (ADHD), and reduced educational achievement. Follow-up to school entry and beyond is thus required to determine the true prevalence and nature of the neurodevelopmental problems arising from preterm birth. Consensus about the assessment used, definitions of disability and health status, age of assessment and who undertakes it are necessary and should allow comparison across populations; this may help to maximise outcomes for children clearly at biological risk. Assessment of outcome for children born preterm beyond two years is required for counselling parents, planning health and education provision, for evaluation of services and to facilitate understanding of the longer term effects of preterm birth on brain development.     

Use of medical services by very preterm children during the first year of life in the Epipage cohort]

OBJECTIVES: To compare the use of health and social services between children born before 33 weeks (very preterm), children born at 33 or 34 weeks (moderately preterm) and children born at 39 or 40 weeks (full term). POPULATION AND METHODS: All very preterm children born in 1997 in nine French regions and a representative sample of the two other groups were followed up since birth. Data on the use of services between discharge from initial neonatal hospitalisation and the 9 months after birth were obtained by mail questionnaire filled in by parents. RESULTS: 38.2% of very preterm children, 24.3% of moderately preterm children and 10.3% of full term children were admitted to hospital at least once. Respiratory tract disorder was the main reason for rehospitalisation of very preterm children. The total number of visits, visits to specialists, and chest therapy were more frequent among very preterm children than among the two other groups. CONCLUSION: Medical care of very preterm children is intensive after discharge from initial neonatal hospitalisation. Need of services are also substantial for moderately preterm children.     

School-age developmental needs in children born preterm

Children born preterm are at risk of developing neurodevelopmental, cognitive and mental health needs. There is an inverse correlation between gestational age and those needs. Difficulties with communication and language, executive function, learning, coordination, behaviour, and mental health tend to become more obvious as the social and academic demand increases in later childhood. By school age, children born preterm without severe neurodisability have often been discharged from neonatal follow-up programmes and opportunities for early recognition are missed. Long term follow-up with enhanced developmental surveillance as well as raising awareness of the consequences of prematurity in school are essential in identifying the needs of children born preterm, so that timely interventions can be implemented. In this article, we draw attention to the school-age developmental needs of children born preterm and the implications for clinical care for this population.     

Preterm birth and carotid diameter and stiffness in childhood

BACKGROUND AND AIM: Low birthweight, either as a result of poor foetal growth or preterm birth, is a risk factor for stroke in adult life. Carotid stiffening, an early marker of atheromatous disease, has been found in low-birthweight children born at term. We hypothesized that carotid artery growth and dynamic properties are permanently affected by preterm birth. METHODS: Carotid artery stiffness and dimensions in 56 school children, 39 born very preterm (mean gestational age [GA] 29 weeks) and 17 controls born at term, were studied by ultrasonic measurements of the pulsatile movements of the vessel wall. RESULTS: The carotid artery diameter was 6.4 mm both in children born preterm and at term (p=0.99). No difference in carotid stiffness was found. Within the preterm group, no differences could be seen between those born small for gestational age (SGA) or appropriate for gestational age (AGA). CONCLUSIONS: Carotid artery elasticity and structure are not altered after preterm birth. The mechanisms behind the increased stroke risk in adults born preterm remain unresolved.     

Die neurologische und kognitive Entwicklung zu klein geborener Kinder

This article aims to provide an overview on the neurological and cognitive outcome of children who were “born too small”. We will discuss the neurodevelopmental prognosis of term born small for gestational age children, and for children born prematurely (appropriate and small for gestational age). The various underlying causes responsible for intrauterine growth retardation (IUGR) and significance for neurodevelopmental outcome will be discussed briefly. Neurodevelopmental outcome of term born children with IUGR due to intrauterine malnutrition and outcome of preterm born small for gestational age (SGA) as well as preterm born appropriate for gestational age (AGA) children will then be discussed in more detail. Children with IUGR represent a heterogeneous group regarding the underlying cause that is responsible for the growth retardation. Neurodevelopmental prognosis very much depends on the specific underlying cause. IUGR caused by intrauterine malnutrition is not necessarily associated with neurodevelopmental problems. However, results of several studies suggest that in term born children with IUGR mild neuromotor problems and lower full scale IQ is more frequent when compared with term born appropriate for gestational age children. Prematurely born children are at high risk for neurodevelopmental impairment. There is no difference in frequency of disabling impairments between AGA and SGA preterm children. However, in preterms with IUGR there seems to be a higher frequency of mild neuromotor problems and cognitive function seems to be poorer than in appropriate for gestational age preterms.     

Follow‐up of adolescents born extremely preterm: cognitive function and health at 18 years of age

Aim: To compare cognitive ability, school achievement and self‐perceived health aspects in adolescents born extremely preterm and term born controls. Method: Fifty‐two, out of 61, extremely preterm born adolescents (mean age 18.4 years) and 54 matched controls (mean age 18.3 years) born at full term were investigated; intelligence quotient was measured with the Wechsler Adult Intelligence Scale; cognitive flexibility, i.e. a measure of visuomotor speed and attention, with the Trail Making Test; school achievement and choice of upper secondary programmes were reported. Health aspects were investigated in a semi structured interview. Result: The adolescents born prematurely had significantly lower IQ than the controls, mean 93 (SD 15.4) vs 106 (12.5), p < 0.001; showed slower visuomotor speed; had lower grades from compulsory school (192.7 vs 234.8, p < 0.001); and chose to a greater extent practical upper secondary school programmes. There were no differences between the groups in health care consumption, prevalence of chronic disease, allergy or infectious diseases. Conclusion: Poorer cognitive performance, in extremely preterm born individuals, seems to persist into late adolescence. Fewer prematurely born than control chose theoretical upper secondary school programmes. However, no difference was noted regarding self‐perceived health aspects.     

Cortical recruitment patterns in children born prematurely compared with control subjects during a passive listening functional magnetic resonance imaging task

OBJECTIVES: To use functional magnetic resonance imaging (fMRI) to test the hypothesis that subjects who were born prematurely develop alternative systems for processing language. STUDY DESIGN: Subjects who were born prematurely (n = 14; 600-1250 g birthweight) without neonatal brain injury and 10 matched term control subjects were examined with a fMRI passive listening task of language, the Clinical Evaluation of Language Fundamentals (CELF) and portions of the Comprehensive Test of Phonological Processing (CTOPP). The fMRI task was evaluated for both phonologic and semantic processing. RESULTS: Although there were differences in CELF scores between the subjects born prematurely and control subjects, there were no significant differences in the CTOPP measures in the 2 groups. fMRI studies demonstrated that the groups differentially engaged neural systems known to process language. Children born at term were significantly more likely to activate systems for the semantic processing of language, whereas subjects born prematurely preferentially engaged regions that subserve phonology. CONCLUSIONS: At 12 years of age, children born prematurely and children born at term activate neural systems for the auditory processing of language differently. Subjects born prematurely engage different networks for phonologic processing; this strategy is associated with phonologic language scores that are similar to those of control subjects. These biologically based developmental strategies may provide the substrate for the improving language skills noted in children who are born prematurely.     

Family functioning, burden and parenting stress 2 years after very preterm birth

Background

Examining rates of difficulties in family functioning following very preterm birth has been a relatively neglected area of research.

Aims

To examine family functioning, burden and parenting stress in families with very preterm compared with term born children, and investigate influences of parental mental health problems and child neurodevelopmental disability on family outcomes in families with preterm children.

Study design

Participants were 184 very preterm and 71 term children and their parents. Parents completed the Family Assessment Device, Parenting Stress Index and Impact on Family questionnaires when their children were 2 years old (corrected for prematurity). Parental mental health and social risk information were also collected. Children were assessed for neurodevelopmental disability.

Results

Families with very preterm children reported poorer family functioning (p = .03) compared with families with term born children, with less evidence for differences between families with very preterm and term born children in parenting stress and family burden. Within very preterm families, parental mental health problems were associated with higher levels of parenting stress (p = .001), and parents of children with a neurodevelopmental disability were more likely to report higher family burden (p = .04).

Conclusions

For families with very preterm children, parental mental health symptoms and child neurodevelopmental disability may identify families at risk of greater stress and burden who may benefit from additional support.     

Difference in mother-child interaction between preterm- and term-born preschoolers with and without disabilities

Aim: To investigate differences in the quality of mother–child interaction between preterm‐ and term‐born children at age 5, and to study the association of mother–child interaction with sociodemographic characteristics and child disability. Methods: Preterm children (n = 94), born at <30 weeks’ gestation and/or birth weight <1000 g, and term children (n = 84) were assessed at corrected age of 5 using a mother–child interaction observation. Disabilities were assessed using an intelligence test, behaviour questionnaires for parents and teachers, and motor and neurological examinations. Results: Mothers of preterm‐born children were less supportive of and more interfering with their children’s autonomy than mothers of term‐born children. This difference was only partly explained by sociodemographic factors. Dyads showed a lower quality of mother–child interaction if children had a severe disability, especially when mothers had a lower level of education. Conclusion: Five years after birth, mother–child interaction of very premature children and their mothers compared unfavourably with term children and their mothers. Mothers with sociodemographic disadvantages, raising a preterm child with severe disabilities, struggle most with giving adequate sensitive support for the autonomy development of their child. Focused specialized support for these at risk groups is warranted.     

Regional fat distribution in children born preterm evaluated at school age

Children born preterm may have aberrant adiposity. At school age, we evaluated body fat and fat distribution in 45 former preterm infants (birth weight < or = 1800 g and gestational age < 34 weeks) and 40 children born at term using dual-energy x-ray absorptiometry. Children born preterm exhibited lower total body fat mass and total body fat mass index compared with children born at term. Fat mass indexes in the limbs but not the trunk were lower in children born preterm than in children born at term. In conclusion, children born preterm, evaluated at school age, may be at risk for altered regional adiposity.     

Is it correct to correct? Developmental milestones in 555 "normal" preterm infants compared with term infants

To determine whether correction for preterm birth should be applied during developmental assessment, we conducted a prospective national survey of very premature infants (born at less than 32 weeks of gestation); neurodevelopment in the first 2 years was studied with the Dutch child health care developmental assessment. In 555 preterm children who had no evidence of handicap at 2 years of age, the age at which developmental milestones were reached was established. The results were compared with the results of the same assessment in Dutch children born at term. During the first year, the development of the very premature children equaled the development of normal children when full correction was applied. At 2 years of age, development was equal to or better than normal children's development without correction. We conclude that full correction for prematurity should be applied in the first year to avoid overreferral for developmental stimulation, whereas at 2 years of age correction is not necessary.     

Pain sensitivity in prematurely born adolescents

BACKGROUND: Several studies reported that preterm infants were found to be hypersensitive to pain. However, longitudinal and quantitative assessments of subsequent pain thresholds in adolescence are scarce. OBJECTIVE: To assess the tenderness threshold in adolescents born prematurely compared with matched children born at full term. DESIGN: Case-control study. SETTING: Children in the community recruited from the files of the neonatal intensive care unit. PARTICIPANTS: Sixty adolescents (aged 12-18 years) born prematurely and 60 adolescents born at full term. MAIN OUTCOME MEASURES: Tenderness thresholds were assessed by tender-point count and by dolorimeter. RESULTS: The preterm-born children had significantly more tender points (6.0 +/- 5.2 vs 3.3 +/- 3.3; P =.001) and lower tender thresholds (4.2 +/- 1.5 vs 4.8 +/- 1.6 kg; P =.04), measured by a dolorimeter, than children born at full term. In both groups, girls had significantly more tender points and lower tender thresholds. Despite their increased tenderness, most of the preterm children did not report pain or other related symptoms. CONCLUSIONS: The fact that preterm-born children and adolescents display higher somatic pain sensitivity may be of relevance to physicians taking care of these children, since they may be prone to developing pain syndromes in the future. Further follow-up studies are needed to confirm this hypothesis.     

Follow‐up of adolescents born extremely preterm: self‐perceived mental health,social and relational outcomes

Aim: The aim of this study was to investigate whether adolescents born extremely preterm differ from full‐term born regarding mental health, social support and attachment style. Methods: Fifty‐one young adults born before the 29th gestational week and 54 born at term were investigated by self‐reports. Psychological health was measured by the Beck Youth Inventories of Emotional and Social Impairment, social support with the Interview Schedule of Social Interaction and attachment style with the Relationship Questionnaire. Results: No difference was noted regarding mental health. The preterm group described themselves as having less social interaction (p ≤ 0.001), but no difference was obtained regarding satisfaction with this circumstance. The prematurely born judged a preoccupied attachment style, concordant with a model of a negative self and positive other, to be applicable more often than the controls (p = 0.02). Conclusion: Extremely preterm born adolescents did not experience more problems regarding mental health compared to controls. Nevertheless, they reported less social interaction and, to a greater extent, a negative model of self.     

Gestational age, birth weight, and the risk of hyperkinetic disorder.

AIMS: To study the association between gestational age and birth weight and the risk of clinically verified hyperkinetic disorder. METHODS: Nested case-control study of 834 cases and 20 100 controls with incidence density sampling. RESULTS: Compared with children born at term, children born with gestational ages of 34-36 completed weeks had a 70% increased risk of hyperkinetic disorder (rate ratio (RR) 1.7, 95% confidence interval (CI) 1.2 to 2.5). Children with gestational ages below 34 completed weeks had an almost threefold increased risk (RR 2.7, 95% CI 1.8 to 4.1). Children born at term with birth weights of 1500-2499 g had a 90% increased risk of hyperkinetic disorder (RR 1.9, 95% CI 1.2 to 2.9), and children with birth weights of 2500-2999 g had a 50% increased risk (RR 1.5, 95% CI 1.2 to 1.8) compared with children born at term with birth weights above 2999 g. The results were adjusted for socioeconomic status of the parents, family history of psychiatric disorders, conduct disorders, comorbidity, and maternal smoking during pregnancy. Results related to birth weight were unchanged after adjusting for differences in gestational age. CONCLUSIONS: Children born preterm, also close to term, and children born at term with low birth weights (1500-2499 g) have an increased risk of clinically verified hyperkinetic disorder. These findings have important public health perspectives because the majority of preterm babies are born close to term.     

Changing panorama of cerebral palsy in Sweden. VIII. Prevalence and origin in the birth year period 1991-94

This 8th Swedish population-based cerebral palsy (CP) report comprises 241 children born 1991-94. The live birth prevalence was 2.12 per 1000. Excluding 7 postnatally-derived cases, the gestational age-specific prevalences were 86 for extremely preterm children, 60 for very preterm and 6 for moderately preterm, and 1.3 for term children per 1000. Spastic hemiplegic, diplegic and tetraplegic subtypes accounted for 33%, 44% and 6%, dyskinetic CP for 12% and simple ataxia for 4%. Neuroimaging had been performed in 90%. Probable aetiology was identified in 73% of preterm and 86% of term children. Among preterm children it was considered prenatal in 12%, peri/neonatal in 61% and unclassifiable in 27%, while it was 51%, 36% and 14% among term children. CONCLUSION: The live birth prevalence for CP in the birth year period 1991-94 continued to decrease slightly. Gestational age-specific prevalences increased marginally in extremely and very preterm births, continued to decrease in moderately preterm births and decreased slightly in term births. Probable aetiology and timing of the brain insult could be revealed in 81%, birth asphyxia being the likely cause in 28% of term children.     

Cholesterol metabolism in 8 to 12-year-old children born preterm or at term

Studies in animals have indicated that cholesterol metabolism is susceptible to manipulation by diet and growth in early life. In humans, low birthweight has been associated with increased risk of coronary heart disease. AIM: To establish whether plasma lipids and indicators of cholesterol absorption, synthesis and breakdown differ in children born preterm and at term. METHODS: Plasma total cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, triacylglycerols, apolipoprotein A1, apolipoprotein B, lathosterol (indicator of cholesterol synthesis), campesterol (indicator of cholesterol absorption), 7-alpha hydroxycholesterol (indicator of cholesterol breakdown) were measured in up to 407 children born preterm and 36 children born at term. RESULTS: Children born preterm had lower cholesterol synthesis (p = 0.002) and lower cholesterol breakdown (p < 0.001) than those born at term, but their plasma cholesterol concentration was not significantly different. After adjusting for current size, birthweight and gestational age were significantly related to plasma lathosterol and 7-alpha hydroxycholesterol. However, when both birthweight and gestational age were adjusted, only gestational age remained significant. There were no significant differences in plasma campesterol between the two groups. CONCLUSION: Being born preterm may have a long-term effect on cholesterol metabolism in children 8-12 y later. Those born prematurely had lower cholesterol synthesis and breakdown, but their plasma cholesterol concentration was similar at this age. These parameters need to be studied in older cohorts.     

Impulse control, working memory and other executive functions in preterm children when starting school

AIM: The aim of this study was to explore whether children born preterm have deficient executive functions (EF) in comparison with children born at full term, and, if so, whether this is dependent on inferior intelligence scores and can be correlated to specific neonatal risk factors and gender. METHODS: In a population-based study, the executive functions of 182 preterm children (birthweight less than 1500 g, VLBW) and 125 controls from the Stockholm Neonatal Project were assessed at 5 1/2 y with a neuropsychological test battery (Nepsy 1990). RESULTS: The controls surpassed the VLBW children on tests of executive functions (EF), even after controlling for intelligence (IQ); a necessary correction since there were significant correlations between measures of EF and IQ. EF was associated with retinopathy of prematurity (ROP), and with visual impairment as a whole. In both groups, girls surpassed boys on tests of executive functions. CONCLUSION: We conclude that it is possible to analyse executive functions already at preschool age. Preterm children are at risk of having subnormal levels of executive functioning, even though their general IQ is normal.     

Learning disabilities in a population-based group of children with hydrocephalus

AIM: To assess cognitive functions in a population-based group of children with hydrocephalus and to analyse differences between children with and without myelomeningocoele (MMC); with hydrocephalus already present at birth and those who developed it later; children born at full term and those born preterm. METHODS: Of 103 children with hydrocephalus born in the western-Swedish region in 1989-1993, 73 were assessed using the Wechsler Intelligence Scales or the Griffith Developmental Scales. RESULTS: One-third of the children were normally gifted (IQ >85), another 30% had a low average IQ of 70-84 and 37% had learning disabilities with an IQ of <70. The median IQ was 75, verbal IQ 90 and performance IQ 76 (p<0.001). An IQ of <70 was found in 19 of 45 (42%) children without MMC and in 8 of 28 (29%) of those with MMC. Children born preterm had a lower IQ of 68 than those born at full term with an IQ of 76, while children with hydrocephalus present at birth but without MMC had a lower IQ of 60 than the others with an IQ of 77. Children with cerebral palsy and/or epilepsy (n=22) had a lower IQ of 66 than the IQ of 78 in those without these impairments (p<0.01). CONCLUSION: Cognitive functions in children with hydrocephalus need to be carefully assessed before school age to ensure adequate support and education. Even the one-third near normally gifted children with an IQ of 70-85 require special attention, due to the profile of relatively well-preserved verbal functions but greatly impaired perceptual and non-verbal abilities.