Long-term Change in the Speech Perception Ability in Pediatric Cochlear Implants and the Effect of the Age at Implantation.

OBJECTIVE: We analyzed the long-term changes in speech perception ability of pediatric cochlear implants (CIs) to evaluate the effect of the age at the time of surgery. STUDY DESIGN: Retrospective. SETTING: Tertiary care academic center. PATIENTS: One hundred fourteen prelingually deaf children with CI use duration >10 years. MAIN OUTCOME MEASURES: Categories of auditory performance (CAP) scores and monosyllabic word recognition scores using the Asan-Samsung Korean word list (ASK-WRS) and a conventional word list (KS-WRS) were the main outcomes. Outcomes were compared according to the age at surgery (group I, 1-2 yr; II, 2.1-3 yr; III, 3.1-7 yr; IV, 7.1-13 yr). RESULTS: CAP scores reached plateaus at 2.6 to 3.3 years post-CI; groups I to III showed better scores than group IV. The maximum CAP score was obtained in all children of groups I to III and in 65% of group IV. ASK-WRSs reached plateaus at 3.2 to 4.8 years post-CI. Younger patients at CI operation showed better ASK-WRSs (97, 93, 90, and 54% in groups I-IV, respectively), but the differences were not significant (I versus II and II versus III). Ceiling effect (perfect score) was observed in early groups (67, 44, 30, and 0% in groups I-IV). KS-WRSs, which is a challenging test, reached plateaus at 7.2 to 8.4 years postsurgery with no ceiling effect. Early implantees showed significantly better scores (88, 82, 73, and 46% in groups I-IV). CONCLUSIONS: Speech perception ability after CI showed audiological age-specific improvement evaluated by various test methods. The most challenging test demonstrated long-term performance differences by the age at CI operation.