Longitudinal cognitive assessment in healthy late preterm infants

Longitudinal cognitive development in late preterm (LP) infants has not been previously evaluated, using structured assessments.

To assess longitudinally cognitive development in a population of healthy LP infants from 12 months to preschool age.

Sixty-two low-risk LP infants (33-36 weeks gestation) with normal or only minor findings on their cranial ultrasound scans were included in the study. They were assessed at 12 and 18 months corrected age using the Bayley Scales of Infant Development II to obtain the mental development index (MDI) and then at preschool age (mean age 62 ± 7 months) using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-R).

The MDI scores obtained at both 12 and 18 months corrected age were within the reported normative range. Using uncorrected ages, their scores were lower at both ages than those obtained using CA (p < 0.01). Full-scale IQ scores within the reported normal range were obtained at 5 years using the WPPSI-R for all but 6 children. Females had significantly higher scores than males (p < 0.001) for the MDI at both 12 and 18 months corrected and uncorrected age. No gender differences were found at preschool age using the WPPSI-R.

Our results suggest that over 90% of the low-risk late preterms reach an MDI and IQ at preschool age within normal range.