Cognitive Assessment of Very Preterm School-age Children by Chronological vs. Corrected Age

Abstract

Children born preterm (≤ 37 weeks) are at higher risk of developing cognitive problems and score lower on cognitive developmental assessments than full-term children. The objective of the paper is to analyse the impact of correction for prematurity on IQ scores amongst preterm born children at school age. A sample of 153 Spanish school-age children were assessed using the WISC-V (Full Scale IQ and all indexes). Assessments were re-scored based on corrected age. Pairwise t-tests were used to analyse the difference in mean IQ scores between corrected age and uncorrected (chronological) age. WISC-V IQ scores < 70, < 85 and < 90 were used to define the cognitive impairment level. Age-corrected scores were significantly higher than chronological age scores, except for processing speed. The percentage of children whose scores could be classified as cognitively impaired was not affected by the correction. When evaluating the cognitive skills in preterm children it should always be indicated whether or not prematurity correction was used, even at older ages, in order to avoid possible biases in the interpretation of the results.