Cognitive and behavioural outcomes following very preterm birth

https://doi.org/10.1016/j.siny.2007.05.004Get rights and content

Summary

This paper provides a review of the cognitive and behavioural outcomes of very preterm children in middle childhood. Case-controlled studies have shown that very preterm children have intelligence quotient (IQ) scores significantly lower than term peers, even for those who are free of severe disability. Authors have noted a gestational age-related gradient in IQ for those born before 33 weeks and studies have revealed particular problems in non-verbal reasoning and simultaneous information processing. Very preterm children are also at risk for behavioural problems. There is little consensus regarding the presence of internalising or externalising behaviours, but most studies show an increased risk of attentional and social problems. Studies have also shown a greater prevalence of psychiatric disorders and, specifically, an increased risk for ADHD. Methodological issues are discussed and suggestions are made for improving the reporting of outcomes to facilitate cross-study comparisons.

Introduction

A timely report by the Nuffield Council on Bioethics examined the complex ethical and practical decisions clinicians increasingly face regarding the intensive care of extremely preterm (EPT) babies.1 This publication is a testament to the vast advances in neonatal care and the marked improvement in survival of babies born at the limits of viability. As increasing numbers graduate from intensive care nurseries, there is warranted concern regarding the future health and well-being of these survivors and an increasing interest in the long term sequelae of prematurity. This paper reviews research relevant to the cognitive and behavioural outcomes of very preterm (VPT) children in middle childhood and considers methodological issues pertaining to outcome monitoring in this population.

Section snippets

Outcome assessments in middle childhood

Although many studies assess outcome at 2 years, it is important to monitor progress beyond this point given the transient or evolving nature of deficits in infancy and the poor predictive validity of infant tests. Whilst the authors of early studies sought to catalogue the severe neurological and sensory disabilities associated with VPT birth, recent research has highlighted a range of more subtle deficits and has shown that the nature of impairment may be changing.2 Cognitive and behavioural

IQ in middle childhood

Researchers have typically studied population-based cohorts of children to define and quantify outcomes for VPT children. As these studies are necessarily large and frequently have limited time and resources with which to assess survivors, outcomes measures have typically comprised an assessment of global cognitive function. The need for objective measures has led to the widespread use of standardised intelligence (IQ) tests as indicators of outcome. IQ tests are psychometric measures that

Behaviour and psychopathology

VPT children are also at greater risk for long term behavioural and emotional sequelae. These outcomes are relatively difficult to compare as the measures used are more diverse than IQ tests. Assessments are usually conducted through self-reports or parental questionnaires and corroborative information from teacher questionnaires may be incorporated as multi-informant information is emphasised for DSM-IV/ICD-10 categorisation. Information can also be obtained from diagnostic interviews, but

How should we report outcomes?

Variability in outcomes may be attributed to variations in study quality that reflect differences in population definitions, the application of comparator data and the selection of outcome measures. An appreciation of study methodology is important in interpreting results and a number of methodological considerations are noted briefly below with recommendations for improving the reporting of outcomes.

Summary and conclusions

There is no question that VPT birth is a major reproductive risk for cognitive and behavioural sequelae, even in children without significant NSI. Whilst VPT children have group mean IQ scores within the normal range, these are significantly lower than their term peers. Cognitive outcome is most compromised in those born at <33 weeks in whom IQ decreases by an average of 1.5–2.5 points for each decreasing week of gestational age. VPT children appear to have the poorest performance on tests of

References (67)

  • K. Stjernqvist et al.

    Ten-year follow-up of children born before 29 gestational weeks: health, cognitive development, behaviour and school achievement

    Acta Paediatr

    (1999)
  • L.A. Foulder-Hughes et al.

    Motor, cognitive, and behavioural disorders in children born very preterm

    Dev Med Child Neurol

    (2003)
  • B. Larroque et al.

    Cognitive status of 5 years old very preterm children: the Epipage Study

    Pediatr Res

    (2005)
  • A. Farooqi et al.

    Chronic conditions, functional limitations, and special health care needs in 10- to 12-year-old children born at 23 to 25 weeks’ gestation in the 1990s: a Swedish national prospective follow-up study

    Pediatrics

    (2006)
  • M. Hack et al.

    Chronic conditions, functional limitations, and special health care needs of school-aged children born with extremely low-birth-weight in the 1990s

    JAMA

    (2005)
  • N. Marlow et al.

    Neurologic and developmental disability at six years of age after extremely preterm birth

    N Engl J Med

    (2005)
  • K. Mikkola et al.

    Neurodevelopmental outcome at 5 years of age of a national cohort of extremely low birth weight infants who were born in 1996–1997

    Pediatrics

    (2005)
  • P. Anderson et al.

    Neurobehavioral outcomes of school-age children born extremely low birth weight or very preterm in the 1990s

    JAMA

    (2003)
  • B. Bohm et al.

    Developmental risks and protective factors for influencing cognitive outcome at 5(1)/(2) years of age in very-low- birthweight children

    Dev Med Child Neurol

    (2002)
  • S.R. Hintz et al.

    Gender differences in neurodevelopmental outcomes among extremely preterm, extremely-low-birthweight infants

    Acta Paediatr

    (2006)
  • M.J. O'Callaghan et al.

    School performance of ELBW children: a controlled study

    Dev Med Child Neurol

    (1996)
  • M. Brothwood et al.

    Prognosis of the very low birthweight baby in relation to gender

    Arch Dis Child

    (1986)
  • S. Saigal et al.

    School-age outcomes in children who were extremely low birth weight from four international population-based cohorts

    Pediatrics

    (2003)
  • D. Wolke et al.

    Entwicklungslanzeitfolgen bei ehemaligen, sehr unreifen Fruhgeborenen

    Monatsschr Kinderheilkunde

    (2001)
  • N. Marlow

    Outcome following preterm birth

  • B.S. Peterson et al.

    Regional brain volume abnormalities and long-term cognitive outcome in preterm infants

    JAMA

    (2000)
  • A.H. Whitaker et al.

    Motor and cognitive outcomes in nondisabled low-birth-weight adolescents. Early determinants

    Arch Pediatr Adolesc Med

    (2006)
  • N. Botting et al.

    Cognitive and educational outcome of very-low-birthweight children in early adolescence

    Dev Med Child Neurol

    (1998)
  • R.W.I. Cooke

    Perinatal and postnatal factors in very preterm infants and subsequent cognitive and motor abilities

    Arch Dis Child Fetal Neonat Ed

    (2005)
  • H.G. Taylor et al.

    Predictors of early school age outcomes in very low birth weight children

    J Dev Behav Pediatr

    (1998)
  • M. Hack et al.

    The effect of very low birth weight and social risk on neurocognitive abilities at school age

    Dev Behav Pediatr

    (1992)
  • L. Ment et al.

    Change in cognitive function over time in very low-birth-weight infants

    JAMA

    (2003)
  • D. Wolke et al.

    Cognitive status, language attainment, and prereading skills of 6-year-old very preterm children and their peers: the Bavarian Longitudinal Study

    Dev Med Child Neurol

    (1999)
  • Cited by (0)

    View full text