Abnormal Cochleovestibular Anatomy and Hearing Outcomes: Pediatric Patients with a Questionable Cochleovestibular Nerve Status May Benefit from Cochlear Implantation and/or Hearing Aids

Abstract

Objective: Imaging characteristics and hearing outcomes in children with cochleovestibular or cochleovestibular nerve (CVN) abnormalities. Study Design: Retrospective, critical review. Setting: Tertiary referral academic center. Patients: Twenty-seven children with CVN abnormalities with magnetic resonance (MRI) and/or computed tomography (CT). Study Intervention(s): None. Main Outcome Measure(s): Determine the likely presence or absence of a CNV and auditory stimulation responses. Results: Two of 27 cases had unilateral hearing loss, and all others had bilateral loss. Eleven (46%) were identified with a disability or additional condition. Twenty-two (42%) ears received a cochlear implant (CI) and 9 ears (17%) experienced no apparent benefit from the device. MRI acquisition protocols were suboptimal for identification of the nerve in 22 (42%) ears. A likely CVN absence was associated with a narrow cochlear aperture and internal auditory canal and cochlear malformation. Thirteen (48%) children with an abnormal nerve exhibited normal cochleae on the same side. Hearing data were available for 30 ears, and 25 ears (83%) exhibited hearing with or without an assistive device. One child achieved closed set speech recognition with a hearing aid, another with a CI. One child achieved open set speech recognition with a CI. Conclusions: Current imaging cannot accurately characterize the functional status of the CVN or predict an assistive device benefit. Children who would have otherwise been denied a CI exhibited auditory responses after implantation. A CI should be considered in children with abnormal CVN. Furthermore, imaging acquisition protocols need standardization for clear temporal bone imaging.

De novo variants in GREB1L are associated with non-syndromic inner ear malformations and deafness

“…Deaf newborn children that have abnormal inner ear anatomy and/or an abnormal CVN could potentially be considered for an auditory brainstem implant (ABI) instead of a cochlear implantation (CI) (Colletti et al 2013). However, current clinical imaging protocols are not fully able to consistently provide cochlear or auditory nerve status information to guide a surgeons’ choice of an auditory prosthesis (Kari et al 2018). Children with unfavorable anatomy for CI may be candidates for an ABI (Colletti et al 2013), although this is currently not yet FDA-approved in the US in children under the age of 12.…”

“…These two interventions carry significantly different risk profiles, and appropriate device selection is of utmost importance. The variability of language and hearing outcomes in children with abnormal CVNs receiving CIs/ABIs coupled with the current inability to predict their outcomes (Kari et al 2018; Young et al 2012; Colletti et al 2013; Birman et al 2016), leads to children enduring multiple assessments and interventions. The sensitive and critical time periods for auditory development are often exceeded by the time needed to determine the most suitable treatment or hindered due to efforts in attempting to understand the progression, delaying language acquisition.…”

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

“…7,8 In other words, while a lateral IAC with four nerves is considered normal, when there are three or four (where the 4th/cochlear nerve is smaller than normal) nerves present, spoken language outcomes tend to be better than when there are 0-2 nerves in the IAC. 7,8 No classification scheme or study based on current imaging characteristics has been able to consistently predict hearing and spoken language outcomes in children with cochleovestibular nerve abnormalities.…”

Compound heterozygous mutations in MASP1 in a deaf child with absent cochlear nerves

“… 4 However, current clinical imaging protocols are unable to consistently predict cochlear nerve status to guide surgeons' choice of auditory prosthesis. 5 Improving preoperative imaging characterization is a subject of widespread research but has not yet reached clinical use.…”

“…The variability of hearing outcomes in children with abnormal cochleovestibular nerves receiving CIs/ABIs coupled with the current inability to predict their outcomes 4 – 7 leads to children enduring multiple assessments and interventions. The length of time to determine which treatment will provide benefit often exceeds the sensitive periods for auditory development, delaying spoken language.…”