Abstract
OBJECTIVE: To access the long-term outcomes of children implanted during most sensitive period for language development. STUDY DESIGN: Literature review. METHOD: 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. RESULTS: Twenty-one reports published from 2004 to 2017 that met the criteria. The range of follow-up was from 3 years to an excess of 10 years. Four => 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 3 to less than 10 years. In 7 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 4 of the 11 studies found that the children achieved a receptive language age level of less than 80%. There were 8 studies which documented the effect of implantation before 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. CONCLUSION: 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 one decline as the age of implantation increases. LEVEL OF EVIDENCE: N/A.