Advances in perinatal care have resulted in continued improvements in the survival of infants born at very low gestational ages. As a result, optimising the quality of children’s lives following premature birth has become increasingly important.Some adverse outcomes of preterm birth, such as cerebral palsy, have become less common over the past 20 years, and serious neurodisability now only occurs in 10% of children born at less than 26 weeks gestation.In contrast, the frequency of other adverse outcomes, such as cognitive and behavioural impairments, has remained fairly constant.
Problems in academic attainment and school performance can apparent from the time children enter school and persist into secondary education.For example, one study found that 6-year-olds born before 28 weeks gestation were 2.85 times more likely to fail an age-appropriate maths assessment than were those born full-term, and other research shows that during primary and secondary years children continue to struggle as evidenced by higher rates of grade repetition and higher rates of use of special educational services. A recent shows that processing speed and working memory (a component of executive function) are strong predictors of overall academic attainment in very preterm children aged 9-10 years, suggesting that impairments in these specific cognitive skills underlie preterms’ poor academic progress. Potentially, early identification of difficulties in processing speed and working memory can allow identification of those in need of intervention, before problems become entrenched and lead to a history of school failure. However, the typical instruments used to examine cognitive outcomes in the first postnatal years of follow up after preterm birth may not be optimal for identifying difficulties in these specific cognitive skills. For example, scores from the Bayley Scales of Infant Development at 2-3 years are not good predictors of processing speed at 5 years. Tests aimed at examining the specific cognitive skills of processing speed and working memory in very young children, rather than global developmental quotients, are therefore needed.
The cognitive impairments observed in children born preterm must be related to alterations in their brain development.Several studies have identified a relationship between white matter abnormalities observed on neonatal magnetic resonance imaging (MRI) scans and difficulties with executive functions later in childhood, and shown a concurrent relation between white matter loss and reduced processing speed in older children who were born preterm. However, little is known about how the trajectories of early brain development relate to emerging cognitive difficulties.
To address these issues, we are currently the UCH Preterm Development Project, a longitudinal study which began in the Fall of 2011 and is targeted at studying brain growth and cognitive-behavioural development in preterms. We perform two brain MRI scans following very preterm birth (<31 weeks of gestation) to obtain growth measures. We then evaluate specific cognitive skills alongside routine clinical follow-up at 3, 6 12 and 30 months of age. This work is funded by SPARKS, UCL Impact and Science without Borders studentships and by Great Ormond Street Children’s Charity.