Development of early auditory and speech perception skills within one year after cochlear implantion in prelingual deaf children

Abstract

Objective To investigate the development of early auditory capability and speech perception in the prelingual deaf children after cochlear implantation, and to study the feasibility of currently available Chinese assessment instruments for the evaluation of early auditory skill and speech perception in hearing-impaired children. Methods A total of 83 children with severe-to-profound prelingual hearing impairment participated in this study. Participants were divided into four groups according to the age for surgery: A (1-2 years), B (2-3 years), C (3-4 years) and D (4-5years). The auditory skill and speech perception 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 and the Mandarin Pediatric Speech Intelligibility (MPSI) test. The questionnaires were used in face to face interviews with the parents or guardians. Each child was assessed before the operation and 3 months, 6 months, 12 months after switch-on. Results After cochlear implantation, early postoperative auditory development and speech perception gradually improved. All MAIS/IT-MAIS scores showed a similar increasing trend with the rehabilitation duration(F=5.743, P=0.007). Preoperative and post operative MAIS/IT-MAIS scores of children in age group C (3-4 years) was higher than that of other groups. Children who had longer hearing aid experience before operation demonstrated higher MAIS/IT-MAIS scores than those with little or no hearing aid experience(F=4.947, P=0.000). 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, only about 40% of the subjects could be evaluated using the most difficult subtest on the MPSI in quiet at 12 months after switch-on. As MCR decreased, the proportion of children who could be tested using the MPSI reduced. Conclusions Within one year after CI , children develop early auditory and speech perception capabilities with time. Chinese versions of the IT-MAIS/MAIS, MESP and MPSI are useful instruments to document early auditory and speech perception skills in children after CI implantation.