Cochlear implantation: long-term functional outcomes

Abstract

The aim of this study is to evaluate the speech perception of profoundly deaf children following cochlear implantation. Material and methods: A prospective study was undertaken on a consecutive group of 138 children. Fifty children (36.3%) were deafened by meningitis, 75 (54.3%) were congenitally deaf, and 13 children (9.4%) were deafened by other causes. All children had received the Nucleus-22 multi-channel cochlear implant and followed a standard rehabilitation programme. No child was lost to follow-up and there were no exclusions from the study. The Iowa Matrix Closed Set Sentence Test and Connected Discourse Tracking were used to assess closed and open set speech perception respectively. Results: On the Iowa Matrix Test, the median score was 0% before implantation, 0% at 1 year, 85% at 2 years, 99% at 3 years, and 100% at 4 and 5 years following cochlear implantation. On Connected Discourse Tracking the median score was 0 words per min (wpm) before implantation, 3 wpm at 1 year, 10 wpm at 2 years, 22 wpm at 3 years, 34 wpm at 4 years and 37 wpm at 5 years following cochlear implantation. Conclusion: A comprehensive rehabilitation programme can help profoundly deaf children develop significant closed set speech perception abilities in the following 2–3 years after cochlear implantation. However, open set speech perception abilities need significantly more time to develop and they do not reach a plateau even 5 years after cochlear implantation.