The development of auditory perception in children following cochlear implantation

The time course for the development of auditory perception in prelingually deaf children following cochlear implantation may extend over many years, thus making long-term studies necessary to evaluate any such outcome. However, few such studies exist in the literature. We prospectively followed-up a consecutive group of 133 prelingually deaf children up to 6 years following implantation. All children were prelingually deaf with age at onset of deafness < 3 years and age at implantation < 8 years. The aetiology of deafness was meningitis for 45 children (34%), congenital deafness for 77 children (58%) and other causes for 11 children (8%). All were implanted with a Nucleus-22 multi-channel cochlear implant and followed the same rehabilitation programme. No child was lost to follow-up and there were no exclusions from the study. Prelingually deaf children showed significant improvement in the auditory perception with implant experience. 82% of children who reached the 6-year interval could understand conversation without lip-reading. The respective percentage in the 4-year interval was 70%. The long-term results of cochlear implantation reveal that the majority of prelingually deaf children, when implanted before the age of 8 years, will develop significant auditory perception.