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. Preteen children are at risk of having subnormal levels of executive functioning, even though their general IQ is normal.