The Relationship between Premature Birth and the Size of Expressive Lexicon in18-36-month-old Children

introduction: the acquisition of speech and language constitutes a dynamic part of twoyear- old children’s growth. expressive lexicon is a key indicator of language ability in these children. premature birth, birth before gestational week 37, is one of the most common risk factors associated with learning skill development. a review of literature suggests inconsistent results on the relationship between preterm birth and the size of expressive lexicon in children. objective: the present study was conducted to investigate the relationship between preterm birth and the size of expressive lexicon in 18-36-month-old persian-speaking children. materials and methods: the present controlled analytical cross-sectional study recruited 18-36-month-old children presenting to 17 shahrivar hospital in rasht, iran. the study children were divided into the term and preterm groups. before beginning the sampling, the children were assigned to three age groups of 13 each, including 18-24 months, 24-30 months and 30-36 months. the data collection tools comprised the 688-itemmacarthur-bates communicative development inventory (cdi, form ii), which was completed by the parents. moreover, all the words were divided into four groups of social terms, common nouns, grammatical words and predicates, and the scores obtained for each category were compared among the groups. the data obtained were assessed using descriptive statistics of mean and standard deviation, and analytical t-test. p<0.05 was set as the level of statistical significance. results: the overall mean size of expressive lexicon was found to be 352.48 ± 177.11in the term children and 240.28 ± 135.93 in preterm ones, suggesting significant differences between the two groups (p=0.002). significant differences were also observed between the term and preterm 18-36-month-old children in terms of common nouns as a dimension of the tool (p=0.01). conclusion: parents seem to play a key role in reducing preterm-birth associated lexicon differences at higher age by teaching their children.