Can Imaging Predict Hearing Outcomes in Children With Cochleovestibular Nerve Abnormalities?

Abstract

Objectives/hypothesis: To identify the imaging characteristics associated with better hearing outcomes found in cochleovestibular nerve (CVN) abnormalities treated with hearing aids and/or cochlear implantation (CI).

Study design: Retrospective review.

Methods: A retrospective review was undertaken of 69 ears with CVN abnormalities seen on magnetic resonance imaging (MRI) treated at a tertiary referral academic center analyzing the clinical features, imaging characteristics, and hearing data. We searched for associations among the hearing and imaging data, hypothesizing that the imaging data was not a good indicator of hearing function.

Results: In univariable analysis of all those who underwent aided testing (hearing aid and CI), health status (P = .016), internal auditory canal (IAC) midpoint diameter (P < .001), and number of nerves in the IAC (P < .001) were predictors of positive hearing outcome. Modiolar abnormalities, cochlear aperture diameter, cochlear malformations, vestibular malformations, and nerves in the cerebellar cistern did not predict hearing outcome (P = .79, .18, .59, .09, .17, respectively). For patients who received CI, health status (P = .018), IAC midpoint (P = .024), and number of nerves in the IAC (P = .038) were significant. When controlling for health status, IAC midpoint diameter (P < .001) and number of nerves in the IAC (P < .001) remained significant. In our cohort, one out of the eight ears (13%) with Birman class 0 or 1 exhibited responses to sound compared to nine out of 13 ears (70%) with Birman class 2-4.

Conclusions: Current imaging modalities cannot accurately depict the status of the cochleovestibular nerve or predict a child's benefit with a CI. Cochlear implantation should be considered in children with abnormal cochleovestibular nerves.

Level of evidence: 3 Laryngoscope, 132:S1-S15, 2022.

Keywords: Cochlear nerve aplasia; cochlear implant outcomes; cochlear nerve deficiency; cochleovestibular malformations; congenital hearing loss.