Intellectual development in a Danish cohort of prematurely born preschool children: specific or general difficulties?

A national cohort of extremely low birth weight (ELBW) and/or extremely preterm (EPT) children and a term control group was followed up at the age of 5 years. The primary objective was to investigate whether premature birth had a global impact on cognitive functions or affected specific functions only. Assessment tools were Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R), Movement Assessment Battery for Children (M-ABC), and subtests from the Neuropsychological Assessment 4-7 years (NEPSY). The mean Full Scale IQ (FSIQ) and M-ABC score of the index children were 1.1 and 1.2 SDs lower than that of the control children (p <.001). Most WPPSI-R subtests showed medium to large differences between index and control children, suggesting a global impact of premature birth on cognitive functions. For both unadjusted and FSIQ adjusted means, no significant group differences on tests of memory or executive function were observed (p >.1), suggesting little impact of premature birth on these specific functions. In this sample, cognitive difficulties in 5-year-old ELBW and/or EPT children tended to be associated with general intellectual difficulties rather than with specific dysfunctions; however, the implications of this finding are ambiguous due to substantial attrition on the NEPSY subtests.