Desarrollo léxico en el prematuro: medidas del vocabulario expresivo en el segundo año de vida

Previous research has shown that lexical and grammatical development may be compromised in very preterm infants, although results from different studies are not always coincident. Expressive lexicon measures were obtained in a sample of healthy very preterm infants (≤ 32 gestation weeks and birth weight ≤ 1500 g), using the MacArthur Communicative Development Inventory at 12, 18 and 24 months of age (corrected for gestation). Data from this sample were compared with results from three independent groups of full term infants born in the same hospital and with comparable language background and socioeconomic status. Significant differences were found in total number of words produced at 18 and 24 months of age, but not at the first age level under analysis. Regarding vocabulary composition, significant differences were observed in all categories under study (social words, nouns, predicates and function words) at 18 months of age, but at 24 months significant differences were restricted to the categories of social words and nouns. Further analysis of the data by gender revealed that differences between full term and preterm infants reached significance in the male subgroup, both at 18 and 24 months of age and for all lexical categories. Taken together these results suggest an initially slower expressive lexicon development in the population of infants born preterm, but differences are only evident from age 18 months and with a higher incidence in the male subgroup. The paper discusses the predictive value of these data for later language outcomes in this at risk population.