Cochlear Implant Effective in Language Development if Implanted at Early Age

What are the long-term outcomes of children implanted with cochlear implants during the most sensitive period for language development?

Bottom Line
The cochlear implant is efficacious in the amelioration of receptive and expressive language deficits in most congenitally deafened children implanted before the age of one. The language outcomes for those implanted after the age of 1 year decline as the age of implantation increases.

Background: It has been more than one-third of a century since cochlear implantation was first utilized to promote the development of language in the prelingually deaf child. Several long-term outcome studies have looked at not only the effects of the cochlear implant on language development but also its effects on broader issues of the quality of life, including educational, economic, and social attainment.

Study design: Literature review.

Synopsis: An initial PubMed search was carried out using the search terms language development and cochlear implant resulted in 1149 citations. A second search was carried out on the initial citations using the criterion of implantation in the period of birth to 24 months, which identified 386 articles. These were analyzed to determine those studies in which linguistic outcome was measured at least three or more years following implantation. Twenty-one reports published from 2004 to 2017 that met the criteria. The range of follow-up was from three years to an excess of 10 years. Four to 10-year follow-up reports were consistent in showing that the earlier the subject is implanted the better the outcome.

Many, but not all, of these children did obtain age-appropriate language. There were 17 reports with follow-up from three to fewer than 10 years. In seven of the 11 studies, the children’s expressive language was reported to have reached an age level of less than 80%. The results for receptive language showed that four of the 11 studies found that the children achieved a receptive language age level of less than 80%.

There were eight studies that documented the effect of implantation prior to 12 months of age and between 12 and 24 months of age, and they all found that the earlier the implantation, the better the outcome for language.

Citation: Ruben RJ. Language development in the pediatric cochlear implant patient. Laryngoscope Inv Oto. Published April 19, 2018. doi: 10.1002/lio2.156.