The Development Of Early Auditory, Speech Perception And Vocabulary Skills After Two Years Of Cochlear Implant Use By Children With Prelingual Hearing Impairment

With the development of our national economy and philanthropic efforts, cochlear implant (CI) has become a common interventions for deaf children. And the number of CI children is expected will increase rapidly in the next few years. While the rehabilitation effects of these children with cochlear implants is paid more and more attention. To investigate the development of early auditory capability, speech perception and vocabulary skills in the prelingual deaf children after cochlear implantation, and to study the feasibility of currently available Chinese assessment tools for the evaluation of early auditory skill, speech perception and language skills in hearing-impaired children.A total of 83 children with severe-to-profound prelingual hearing impairment participated in this study. The auditory, speech perception and vocabulary ability of CI children were evaluated by trained audiologists using the infant-toddler/meaningful auditory integration scale (IT-MAIS/MAIS) questionnaire, the Mandarin Early Speech Perception (MESP) test, the Mandarin Pediatric Speech Intelligibility (MPSI) test, Chinese communicative development inventory (CCDI) and mandarin expressive and receptive vocabulary test (MERVT). The questionnaire was conducted in a face to face interview with the parents or guardians, and other closet and vocabulary tests were evaluated by children accompanied with audiologists. Each one was assessed before the operation and 3 months,6 months,1 year and 2 years after switch-on.Results show that early postoperative auditory development, speech perception and vocabulary skills gradually improved with cochlear implantation. All MAIS/IT-MAIS scores with the extension of rehabilitation time, showed a similar trend. Children who had longer hearing aid use experience before operation demonstrated MAIS/IT-MAIS scores higher than those with little or no hearing aid use. The MESP test showed that, children were not able to perceive speech as well as detecting speech signals. However as the duration of CI use increased, speech perception ability also improved substantially. However, almost all the subjects could be evaluated using the most difficult subtest on the MPSI in quiet only at 2 years after switch-on. As MCR decreases, the proportion of children who could be tested using the MPSI reduced. The vocabulary increased with an increase in the duration of CI use, and the receptive vocabulary developed earlier than the expressive one.Results from this study suggest that children developed early auditory, speech perception and vocabulary capabilities after two years of CI use, which gradually improved with longer CI use. It not only has a certain order, and showed synergistic trend:the first to develop hearing and speech recognition ability, then to quickly improve word’s comprehensive and expressive ability. Development of comprehension precedes the expression ability of vocabulary. Hearing aids could be selected by younger children before cochlear implantation, while older children should wear hearing aids before surgery to contact sound as soon as possible. After two years of cochlear implantation, children could compete with the 2-year-old normal hearing children in hearing, speech perception and language ability. Chinese versions of the IT-MAIS/MAIS, MESP, MPSI, CCDI and MERVT are useful tools to document early auditory, speech perception skills and language ability in children after implantation.