Abstract
It is impossible to learn the spoken language for infants with hearing loss of more than 100 dB by the use of hearing aids, as they cannot discriminate speech sounds. Acquisition of a normal language is inly guaranteed for very young children. It is several years since cochlear implants have been popularly applied for the young deaf children, and most of them have shown a remarkable improvement in speech ability after two years' training. Therefore, cochlear implants should preferably be performed for congenital deaf children up to the age of one to three, instead of continuing the auditory-oral training with hearing aids. This recommendation is also reasonable from the study on maturational changes of the auditory cortex of the brain.
