Communication benefits of bilateral cochlear implantation. Retrospective study in 12-year-old children

Introduction and objectives: Some studies suggest that simultaneous or sequential cochlear implantation in a short period of time offers additional benefits. There is controversy regarding the existence of an age limit after which a second implantation offers less benefit for the acquisition of communication skills. The objectives of this study were to confirm that sequential cochlear implantation offers benefits compared to unilateral implantation and to study whether, at 12 years of age, there are significant differences regarding the age at the time of the second implantation.

Methods: Descriptive and observational study of a population of 12-year-old children carrying cochlear implants (n=69). A liminal pure tone audiometry and an open-field verbal discrimination test (disyllables, common phrases in an open context, with and without noise) were conducted to evaluate audiological benefits.

Results: Verbal discrimination results were better among patients who had been implanted before the age of 2 years, although the differences were not statistically significant (P>.5). Children who had received bilateral cochlear implants before the age of 2 years and with a period less than 4 years between both implants presented better verbal discrimination percentages (P<.05).

Conclusions: In our sample, early cochlear implantation with a short period between both implants provided significant benefits regarding intelligibility. There seem to be a specific age and interimplant period, after which the auditory benefit on the first implant becomes reduced.