Cochlear nerve aplasia - unilateral

Case contributed by Oana Harsan


Right sided sensorineural hearing loss with. No motor or language developmental delay.

Patient Data

Age: 3 years
Gender: Female

Unremarkable brain parenchymal and CSF-space study.

Right internal auditory canal demonstrates cochlear nerve and cochlear aperture aplasia, associated with normal right cochlear morphology and normal IAC diameter. 

Left internal auditory canal unremarkable.

Case Discussion

Around 20% of congenital sensorineural hearing loss have detectable imaging findings1.

This case illustrates an isolated, non syndromic unilateral congenital cochlear nerve and cochlear aperture aplasia, in the presence of a normal cochlea. Images acquired on 1.5 T machine, distinction between hypoplastic and aplastic nerve may be difficult, however there seems to be no cochlear aperture. The lack of cochlear aperture in also in favor of congenital and not acquired hearing loss, as normal size IAC may raise this issue 2.

Sagittal-oblique images should be systematically reviewed in cases of congenital SNHL even when there is no abnormal IAC diameter, nor structural cochlear/vestibular anomalies.

Possible treatments include rerouting auditory stimuli to contralateral healthy ear. Cochlear implants are rarely successful 3.

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Case information

rID: 87910
Published: 7th Apr 2021
Last edited: 9th Apr 2021
Inclusion in quiz mode: Included
Institution: Centre Hospitalier de Pau

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