Examination of the vocabulary before and after elementary school period in hearing-impaired children with cochlear implants.

Abstract

　In this study, we examined vocabulary development in the early stage of younger cochlear implantees who had undergone the implant surgery by the age of five. Subjects were divided into six groups according to the results of the Japanese Picture-Vocabulary-Test (PVT). Thirty-two out of 88 subjects (36.4%) showed a good vocabulary development index (VDI>85), comparable to that of their hearing age peers, while 56 (63.6%) showed only fair (VDI<84) or poor (VDI<49) vocabulary development. The average age at the time of surgery was significantly lower in the children in whom the VDI had exceeded 85 by the age of four. On the contrary, the age at the time of the first hearing aid trial and the hearing threshold with cochlear implant showed no relationship to the VDI. In regard to the communication mode, most of the children tried to enhance their oral communication skill before enrollment to primary school, however, after enrollment, some in the poorly vocabulary development group (VDI<49) started to use sign language. It is essential to support hearing-impaired children over the long term on the basis of the understanding that they need better vocabulary proficiency, reading and speaking abilities, and social skills in order to communicate with people in the society.