Language understanding and vocabulary of early cochlear implanted children

The aim of the study was to identify factors associated with the level of language understanding, the level of receptive and active vocabulary, and to estimate effect-related odds ratios for cochlear implanted children's language level.

The patient material included all children born in Denmark between January 2005 and January 2011, having received a cochlear implant (CI) and with a minimum of 6 months of hearing with their CI (N=94). The participation rate was 88% (N=83). Sixty-eight (82%) of the participating children were implanted bilaterally. Mean age at implantation was 19.6 months. The mean age at test was 46.3 months and the mean age of hearing with CI was 25.9 months. The children were tested with three different tests, the PPVT-4, the Reynell receptive part and a Danish test "Viborgmaterialet" for active vocabulary. Logistic regression models were used for analysis of the potential influence of eighteen different factors upon the test outcomes.

The majority of children did not have age equivalent language understanding and vocabulary. There was significant effect of the following factors upon the test outcomes: age at hearing aid start before implantation, age at implantation, length of hearing, communication mode, mode of implantation, amount of support teaching, residence and educational placement. Children who started HA treatment before 6 months of age, were implanted before 12 months or did not use total communication had the highest odds of having age equivalent language understanding and vocabulary.

The majority of hearing impaired children in Denmark received hearing aids before six months of hearing and the majority was implanted before 18 months of age. Despite these medical and technical advances the vast majority did not have age equivalent language understanding and vocabulary. Data suggest that the language gap is not closed in two years after implantation.