Long-Term Functional Hearing Preservation in Pediatric Cochlear Implant Recipients

Objective: To evaluate long-term functional hearing preservation (FHP) in pediatric cochlear implant recipients and identify key predictors, including electrode array length, preoperative thresholds, and presence of inner ear malformations. Study design: Retrospective case review. Setting: Tertiary referral center. Patients and intervention: We reviewed 113 ears of children with preoperative acoustic hearing (≤65 dB HL at 250 Hz) who received a cochlear implant (CI) from a single manufacturer. Data were collected over a mean follow-up of 4 years (range: 0.2 to 8.7 y). Main outcome measures: Functional hearing preservation (FHP), was defined as an unaided threshold of ≤80 dB HL at 250 Hz. The percentage of FHP was calculated for each patient. Outcomes were analyzed using Kaplan-Meier survival analysis and mixed-effects modeling to evaluate short-term (1 y) and long-term (5 y) predictors of FHP. Results: Across all ears, survival estimates for FHP were 0.70 at 1 year and 0.57 at 5 years. Children with EVA demonstrated poor durability of residual hearing, with a survival probability of 0.36 at 1 year and no probability of retaining functional hearing beyond 2 years. In contrast, ears without EVA showed greater potential for preservation: 0.76 at both 6 months and 1 year, 0.72 at 2 years, and 0.62 at 5 years. Hearing preservation was significantly influenced by electrode array length, preoperative thresholds (short-term), presence of EVA, and time since surgery. Short-term and long-term hearing preservation was not significantly influenced by age at implantation. Conclusions: Functional hearing preservation is achievable in a substantial proportion of children, particularly with 24 mm arrays and in the absence of inner ear malformation. Outcomes decline progressively over time, particularly for cases of EVA. This study underscores the need for tailored surgical and rehabilitation strategies and long-term monitoring in this population.