Yoshinaga-Itanoの聴覚障害児の言語発達に関する早期臨界期説批判

抄録

During the period from 1968 to 2000, more than 2000 young hearing-impaired children participated in my home training program. The present study was undertaken to confirm the validity of Yoshinaga-Itano's hypothesis that the period of early infancy is critical for language development in hearing-impaired children based on the outcomes of 12 illustrative cases selected from those who had previously participated in my home training program. These children were followed up for more than 15 years. They included two company employees who had graduated from universities, two medical students, a dentist, a pharmacologist, a molecular biologist, a writer of juvenile songs, a worker at an industrial home for the handicapped with cerebral palsy and mental retardation associated with severe hearing loss, a woman who selected to live with deafness, a deaf teacher for a school for the deaf and a deaf student of a professional school. These cases had attained a high proficiency of literacy, although they were older than one and half years when they participated in my home training program. The outcomes of these cases suggest that long-lasting parental support and school education are the most important factors for attaining a high level of language development rather than the age at which the hearing loss is detected. These findings do not support Yoshinaga-Itano's hypothesis.
(This work was supported by a Grant for Child Health and Development (17C-3) from the Ministry of Health Labor and Welfare)