[Early vocabulary development in Mandarin children with cochlear implantation]

Objective: To investigate the development of receptive and expressive vocabulary in Mandarin-speaking children with cochlear implants (CI) during the first year after CI activation. Methods: A total of 827 children (411 boys and 416 girls) who were implanted CI before 2.5 years of age from October 2019 to December 2022 in the Department of Auditory Implantation, Shandong Provincial ENT Hospital were included in this study. The Infant Checklist of the Mandarin Early Vocabulary Inventory (EVI) was used to assess the quantity and content of receptive and expressive vocabulary at the time of CI activation and at the 1st, 3rd, 6th, 9th, 12th months post-activation. SPSS 22.0 was used to describe the receptive and expressive vocabulary of CI children at the first year after activation. Results: During the first year after CI activation, CI children's receptive and expressive vocabulary consistently increased with the CI usage. The average number of receptive vocabulary and expressive vocabulary respectively increased from 0 to 178, and from 0 to 97. At the first year of post-activation, the number of receptive and expressive vocabulary of CI children were superior to that of hearing-age matched typical-hearing children, but fell behind of that of chronological age matched typical-hearing children. In terms of lexical categories, receptive and expressive vocabulary was acquired in the following order: nouns, verbs, adjectives, and pronouns. Among the top 50 words that CI children could express, nouns were the most common, then followed by verbs, adjectives, and pronouns. Father's education level can significantly and positively predictethe receptive vocabulary of CI children at the first year post-activation. At the first year after CI activation, the 10th, 25th, 50th, 75th, and 90th percentiles were 113, 149, 178, 202, 223 for the receptive vocabulary, and 9, 37, 97, 148, 188 for expressive vocabulary. Conclusion: For Mandarin speaking children with CI, the receptive and expression vocabulary continuely increased within the first year after CI activation. The ability to grasp receptive vocabulary precedes the ability to express expressive vocabulary. Compared to hearing-age matched typical-hearing children, CI children showed faster rate of the vocabulary growth, and earlier and more frequently verb expression. However, it still larged behind that of chronological age matched hearing normal children. CI children respectively understood and expressed nouns and verbs the first. In children with CI, the first concepts understood and expressed were nouns and verbs. Among the first 50 words expressed, nouns were the most numerous, and the age at which verbs were acquired was earlier than that for hearing-age matched typical-hearing children.