TANAKA Yoshisato, KODERA Kazuki, KITA Yoshiko, SAITO Hiroshi
The Japan Journal of Logopedics and Phoniatrics, 40(4) 329-341, Oct, 1999
The present paper reports details of the development of auditory functions and language before and after cochlear implantation in two young children with congenital deafness.<BR>The first case was a boy. When he was one year and six months old, he was given a hearing aid and received auditory training at a rehabilitation center. In spite of efforts to achieve maximal use of the hearing aid, no amplification effect was observed. When he was two years and nine months old, he visited our clinic and was diagnosed as having total deafness above 130 dB. He was enrolled in our home training program. In order to facilitate the development of communication skills as well as language, manual communication including cued speech, finger spelling and gestures was recommended for use between the child and his parents and teachers. This approach was successful, and he soon began to acquire language through vision. When the boy reached four years of age, he received a cochlear implant (Nucleus 22channel device) in the right ear, but subsequent development of auditory functions was very slow and limited. When the boy was four years and ten months old, the author introduced a top-down method based on a neuropsy-chological hypothesis in order to facilitate the development of auditory analytic-synthetic functions in the brain. The child was shown characters or written words which he already knew, and he was asked to imitate the author's pronounciation of these teaching materials. By means of this method, he gradually came to understand spoken words mainly through audition.<BR>The second case was a girl. At the age of one year and nine months, she was diagnosed as having profound hearing loss. She was immediately enrolled in our home training program, in which she was given a body-worn hearing aid. After finishing the program, she was referred to a school for the deaf, where she received auditory training and language education by auditory-oral method. According to her mother's statement, the girl never responded to environmental noises except for the sound of a drum. When she was four years and five months old, she visited our clinic again because of the poverty of her auditory response. Audiometry demonstrated that she had extremely profound hearing loss above 130 dB but retained minimal residual hearing in the low frequency range of the left ear. She received implant surgery in the right ear at the age of five years and six months. Her postoperative development of auditory functions was clearly better than that of the first case, even though her age at implantation was higher than that of the first case.<BR>The findings obtained from these two cases suggest that early auditory experiences before cochlear implantation may positively influence the effect of a cochlear implant. They further imply that careful use of manual communication prior to cochlear implantation does not necessarily interfere with postoperative development of auditory perceptual functions.