Age and outcome of cochlear implantation for patients with bilateral congenital deafness in a Cantonese-speaking population.

Objective: To evaluate the effect of age at implantation by assessment of speech perception in cochlear implant users with bilateral congenital deafness.
Design: A retrospective cohort analysis of 60 cochlear implant users (age at implantation, 1.01 to 22.0 yr) who have at least 2 yr of experience. Their outcome performance was defined by the change in i) speech perception category (SPC) score based on postoperative assessment results and ii) the type of education attended after implantation. The association of age at implantation with SPC scores was analyzed at different ages at implantation (2, 3, 4, 5, and 6 yr old). The SPC scores for a particular age at implantation were compared at 6, 12, and 24 mo after implantation. The impact of age at implantation on choice of education was evaluated by analyzing the transition from a school for the deaf to mainstream education for the 45 children who were operated on before the age of 10, because older children are less likely to make such a change.
Results: Children implanted at the ages of 2, 3, 4, 5, and 6 yr all obtained significant improvements in SPC scores 24 mo after implantation. The greatest improvement was noted at 24 mo after implantation among those operated on before age 3. For all age groups, improvement at 24 mo after implantation is greater than at 12 mo, whereas the latter is greater than the improvement noted at 6 mo after implantation. Comparison of children implanted before the age of 3 and between ages 3 and 10 showed a significant difference in the choice of education after implantation. Children who were implanted before the age of 3 were more likely to attend mainstream education after implantation.
Conclusion: Results from the present study are consistent with the current belief that implantation at a younger age provides greater benefit. The proportion of children attending mainstream education was significantly higher for those implanted before age 3, which may be a potential benefit to early implantation for relieving the burden of governments in providing special education.