Executive Function and IQ Predict Mathematical and Attention Problems in Very Preterm Children

Objective of this study was to examine the impact of executive function (EF) on mathematical and attention problems in very preterm (gestational age <= 30 weeks) children. Participants were 200 very preterm (mean age 8.2 +/- 2.5 years) and 230 term children (mean age 8.3 +/- 2.3 years) without severe disabilities, born between 1996 and 2004. EFs assessed included verbal fluency, verbal working memory, visuospatial span, planning, and impulse control. Mathematics was assessed with the Dutch Pupil Monitoring System and parents and teachers rated attention problems using standardized behavior questionnaires. The impact of EF was calculated over and above processing speed indices and IQ. Interactions with group (very preterm versus term birth status) were examined. Analyses were conducted separately for two subsamples: children in preschool and children in primary school. Very preterm children performed poorer on tests for mathematics and had more parent and teacher rated attention problems than term controls (beta(s) > .11, P-s < .01). IQ contributed unique variance to mathematics in preschool and in primary school (beta(s) > .16, P-s < .007). A significant interaction of group with IQ (beta = -.24, P = .02) showed that IQ contributed unique variance to attention problems as rated by teachers, but that effects were stronger for very preterm than for term infants. Over and above IQ, EF contributed unique variance to mathematics in primary school (beta = .13, P < .001), to parent rated inattention in preschool and in primary school (beta(s) > -.6, P-s < .04), and to teacher rated inattention in primary school (beta = -.19; beta = .19, P-s < .009). In conclusion, impaired EF is, over and above impaired IQ, an important predictor for poor mathematics and attention problems following very preterm birth.