Early risk predictors for impaired numerical skills in 5-year-old children born before 32 weeks of gestation

Abstract

Aim: To unravel risk predictors for impaired numerical skills at 5 years of age in a population-based cohort of very preterm infants.

Methods: Between January 2003 and August 2006, we prospectively enrolled all infants born in Tyrol with <32 weeks of gestation. A total of 161 of 223 preterm infants (participation rate 72.2%) had a detailed examination at 5 years of age including cognitive assessment (Hannover-Wechsler Intelligence Test for preschool children, third edition (HAWIVA-III) or Snijders-Oomen Nonverbal Intelligence Test (SON-R)). In 135 children, numerical abilities were assessed with the dyscalculia test TEDI-MATH. The association between pre- and postnatal factors and impaired numerical skills was analyzed by means of logistic regression analysis.

Results: Dyscalculia test showed delayed numerical skills (TEDI-MATH Sum T-score <40) in 27 of 135 children tested (20.0%). In half of the children tested, delayed numerical abilities were related to lower IQ scores. Smoking in pregnancy, intracerebral haemorrhage and chronic lung disease were predictive of delayed numerical skills at 5 years of age in the multivariate analysis.

Conclusion: This study identified risk predictors for impaired numerical skills in preterm infants. Our data support the role of both pre- and perinatal factors in the evolution of mathematical deficits.