Eight-year-old very and extremely preterm children showed more difficulties in performance intelligence than verbal intelligence

Abstract

Aim: This study determined possible discrepancies between verbal IQ and performance IQ in 8-year-old very preterm (VPT) and extremely preterm (EPT) children, and examined associations between verbal IQ and performance IQ, and sociodemographic factors, perinatal factors, early cognitive outcomes and also with school achievement scores. Methods: This prospective cohort study included 120 eight-year-old VPT/EPT children. Cognitive development was assessed at the ages of 2, 5 and 8 years. Eight years’ school achievement results in arithmetic, reading and spelling were collected. Multiple regression analyses were performed to determine predictors of verbal IQ and performance IQ at the age of 8 years and to determine associations with school achievement scores. Results: Mean performance IQ (89.8) was significantly lower than mean verbal IQ (99.4; Cohen's d = 0.59) at the age of 8 years. Gestational age (GA), small for GA status, and cognitive scores at the ages of 2 and 5 years significantly predicted verbal IQ and performance IQ at the age of 8 years. Performance IQ at age 8 years was an important predictor for arithmetic scores (β = 0.42). Conclusion: Performance IQ was more strongly affected than verbal IQ in 8-year-old VPT/EPT children and was strongly related to mathematical difficulties.