Age at implantation: its importance in pediatric cochlear implantation

To assess the influence of age at implantation on speech perception and speech intelligibility following pediatric cochlear implantation.

A prospective study was undertaken on a consecutive group of 126 congenital and prelingually deaf children up to 4 years after implantation. The study group was confined to prelingually deaf children less than 7 years of age at the time of implantation. All had implantation with the same multichannel cochlear implant system. No child was lost to follow-up, and there were no exclusions from the study.

The Iowa Matrix Closed Set Sentence test, connected discourse tracking, categories of auditory performance, and speech intelligibility rating were used to assess the speech perception (closed and open set) and speech intelligibility of the children with implants. Regression analysis and Spearman rank correlation coefficients were used to assess the correlation between the outcome measures with age at implantation. The setting was a tertiary referral pediatric cochlear implant center in the United Kingdom.

Age at implantation positively correlated with preimplantation assessment performance and with most of the outcome measures up to 24 months following implantation. However, at the 3-and 4-year intervals following implantation, age at implantation was found to be a strong negative predictor of all the outcomes studied (correlation coefficients ranging from -0.44 to -0.58, all statistically significant [P<.05]).

The results of the present study provide strong evidence that prelingually deaf children should receive implants as early as possible to facilitate the later development of speech perception skills and speech intelligibility and thus maximize the health gain from the intervention. However, because of the wide variation in individual outcomes, age alone should not be used as a criterion to decide implant candidacy.