Cochlear implants and sensory aids for deaf children

Cochlear implant in the second year of life: lexical and grammatical outcomes

PURPOSE

The authors studied the effect of the cochlear implant (CI) on language comprehension and production in deaf children who had received a CI in the 2nd year of life.

METHOD

The authors evaluated lexical and morphosyntactic skills in comprehension and production in 17 Italian children who are deaf (M = 54 months of age) with a CI and in 2 control groups of children with normal hearing (NH; 1 matched for chronological age and the other whose chronological age corresponded to the duration of CI activation). The authors also compared children with unilateral CI to children with bilateral CI.

RESULTS

Children with CI appeared to keep pace with NH children matched for time since CI activation in terms of language acquisition, and they were similar to same-age NH children in lexical production. However, children with CI showed difficulties in lexical comprehension when a task required phonological discrimination as well as in grammar comprehension and production. Children with bilateral CI showed better comprehension than did children with unilateral CI; the 2 groups were similar for production.

CONCLUSIONS

Activation of CI in the 2nd year of life may provide children who are deaf with a good opportunity to develop language skills, although some limitations in phonological and morphological skills are still present 3 years after auditory reafferentation.

Development of Language and Speech Perception in Congenitally, Profoundly Deaf Children as a Function of Age at Cochlear Implantation

Like any other surgery requiring anesthesia, cochlear implantation in the first few years of life carries potential risks, which makes it important to assess the potential benefits. This study introduces a new method to assess the effect of age at implantation on cochlear implant outcomes: developmental trajectory analysis (DTA). DTA compares curves representing change in an outcome measure over time (i.e. developmental trajectories) for two groups of children that differ along a potentially important independent variable (e.g. age at intervention). This method was used to compare language development and speech perception outcomes in children who received cochlear implants in the second, third or fourth year of life. Within this range of age at implantation, it was found that implantation before the age of 2 resulted in speech perception and language advantages that were significant both from a statistical and a practical point of view. Additionally, the present results are consistent with the existence of a 'sensitive period' for language development, a gradual decline in language acquisition skills as a function of age.