Cognitive trajectories from infancy to early adulthood following birth before 26 weeks of gestation: a prospective, population-based cohort study

Abstract

ObjectiveTo determine the trajectory of cognitive test scores from infancy to adulthood in individuals born extremely preterm compared with term-born individuals.DesignA prospective, population-based cohort study.Setting276 maternity units in the UK and Ireland.Patients315 surviving infants born less than 26 completed weeks of gestation recruited at birth in 1995 and 160 term-born classroom controls recruited at age 6.Main outcome measuresBayley Scales of Infant Development-Second Edition (age 2.5); Kaufman Assessment Battery for Children (ages 6/11); Wechsler Abbreviated Scale of Intelligence-Second Edition (age 19).ResultsThe mean cognitive scores of extremely preterm individuals over the period were on average 25.2 points below their term-born peers (95% CI −27.8 to −22.6) and remained significantly lower at every assessment. Cognitive trajectories in term-born boys and girls did not differ significantly, but the scores of extremely preterm boys were on average 8.8 points below those of extremely preterm girls (95% CI −13.6 to −4.0). Higher maternal education elevated scores in both groups by 3.2 points (95% CI 0.8 to 5.7). Within the extremely preterm group, moderate/severe neonatal brain injury (mean difference: −10.9, 95% CI −15.5 to −6.3) and gestational age less than 25 weeks (mean difference: −4.4, 95% CI −8.4 to −0.4) also had an adverse impact on cognitive function.ConclusionsThere is no evidence that impaired cognitive function in extremely preterm individuals materially recovers or deteriorates from infancy through to 19 years. Cognitive test scores in infancy and early childhood reflect early adult outcomes.

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

“…That is, the perinatal development of the brain is not complete before preterm birth, resulting in widespread disruptions in the frontoparietal network, 8 the integrity of which is associated with optimal executive function, processing speed, and intelligence. The lack of association between cognitive impairment and age at assessment implies that children born very prematurely do not 'catch up' with their termborn peers through childhood and adolescence; that is, children born preterm suffer from a deficit in cognition, not a delay, supporting the findings of Linsell et al, 90 who found no evidence of recovery or deterioration of cognitive function in extremely preterm individuals from infancy to young adulthood (also see Doyle and Anderson 91 for a review of adult outcomes of extremely premature birth). Furthermore, when the studies were split into subgroups of younger (4-10y) and older children (11-17y) effect sizes were very similar between groups, although moderating effects were found to be associated with study effect size in the younger children (birthweight was associated with intelligence study effect size, and continuous gestational age was associated with executive function study effect size).…”

“…The second implication of these findings is related to the non-significant correlations between age at assessment and the effect sizes of each study, and the consistent effect sizes between the younger and older subgroups. The lack of association between cognitive impairment and age at assessment implies that children born very prematurely do not 'catch up' with their termborn peers through childhood and adolescence; that is, children born preterm suffer from a deficit in cognition, not a delay, supporting the findings of Linsell et al, 90 who found no evidence of recovery or deterioration of cognitive function in extremely preterm individuals from infancy to young adulthood (also see Doyle and Anderson 91 for a review of adult outcomes of extremely premature birth).…”

Stability of general cognition in children born extremely preterm as they grow older: good or bad news?

“…Because few quality long-term longitudinal studies exist, the answer is unclear. In Archives of Disease in Childhood , Linsell and colleagues addressed this important question using data from the EPICure study,1 which assessed cognitive functioning at 2.5, 6, 11 and 19 years of age in survivors born <26 weeks’ gestational age in the UK and the Ireland over 10 months in 1995. Their major finding was that poor cognitive function in EP survivors persists throughout childhood into late adolescence/early adulthood.…”

Highlights from this issue

“…The third Editorial in this issues relates to the article on the cognitive trajectories of extremely preterm infants by Louise Linsell and colleagues that was published in the April issue of the main edition of the journal 1. The article described cognitive assessments of preterm infants who were born before 26 weeks of gestation and then assessed using age standardised intruments at 2 to 3 years (Bayley), 6 to 9 years (Kauffman) and 19 years (Wechsler).…”