Executive and Memory Function in Adolescents Born Very Preterm

Abstract

Many preterm children display school difficulties, which may be mediated by impairment in executive function and memory. To evaluate executive and memory function among adolescents born preterm compared with term controls at 16 years. A total of 337 of 437 (77%) adolescents born in 1989 to 1992 with a birth weight < 1250 g and 102 term controls were assessed with a battery of executive function and memory tasks. Multiple regression analyses were used to compare groups and to identify associations between selected factors and outcomes among preterm subjects. Adolescents born preterm, compared with term controls, showed deficits in executive function in the order of 0.4 to 0.6 SD on tasks of verbal fluency, inhibition, cognitive flexibility, planning/organization, and working memory as well as verbal and visuospatial memory. After exclusion of adolescents with neurosensory disabilities and full-scale IQ < 70, significant group differences persisted on most tests. Preterm subjects, compared with term controls, were at increased risk of exhibiting problems related to executive dysfunction, as measured with the Behavior Rating Inventory of Executive Function, on the Metacognition Index (odds ratio [OR]: 2.5 [95% confidence interval (CI): 1.2-5.1]) and the Global Executive Composite (OR: 4.2 [95% CI: 1.6-10.9]), but not on the Behavioral Regulation index (OR: 1.5 [95% CI: 0.7-3.5]). Among adolescents born preterm, severe brain injury on neonatal ultrasound and lower maternal education were the most consistent factors associated with poor outcomes. Even after exclusion of preterm subjects with significant disabilities, adolescents born preterm in the early 1990s were at increased risk of deficits in executive function and memory.