Functional Outcomes of Cochlear Implantation in Children with Bilateral Cochlear Nerve Aplasia

Many otologists face a dilemma in the decision-making process of surgical management of patients with cochlear nerve (CN) aplasia. Currently, evidence on cochlear implantation (CI) outcomes in patients with CN aplasia is limited. We scrutinized functional outcomes in 37 ears of 21 children with bilateral CN aplasia who underwent unilateral or bilateral CI based on cross-sectional and longitudinal assessments. The Categories of Auditory Performance (CAP) scores gradually improved throughout the 3-year follow-up; however, variable outcomes existed between individuals. Specifically, the majority of recipients with a 1-year postoperative CAP score ≤1 remained steady or achieved awareness of environmental sounds, while recipients with early stage hearing benefit had markedly improved auditory performance and could possibly discriminate some speech without lipreading. Meanwhile, intraoperative electrically evoked compound action potential was not correlated with postoperative CAP score. The dynamic range between T and C levels remained unchanged. Our results further refine those of previous studies on the clinical feasibility of CI as the first treatment modality to elicit favorable auditory performance in children with CN aplasia. However, special attention should be paid to pediatric patients with an early postoperative CAP score ≤1 for identification of unsuccessful cochlear implants and switching to auditory brainstem implants.