Cochlear nerve aplasia - unilateral
Right sided sensorineural hearing loss with. No motor or language developmental delay.
Loading Stack -
0 images remaining
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.
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.
- 1. Sennaroğlu L, Bajin MD. Classification and Current Management of Inner Ear Malformations. Balkan Med J. 2017 Sep 29;34(5):397-411. doi: 10.4274/balkanmedj.2017.0367. Epub 2017 Aug 25. PMID: 28840850; PMCID: PMC5635626.
- 2. Glastonbury CM, Davidson HC, Harnsberger HR, Butler J, Kertesz TR, Shelton C. Imaging findings of cochlear nerve deficiency. (2002) AJNR. American journal of neuroradiology. 23 (4): 635-43. Pubmed
- 3. Eva Orzan, Giulia Pizzamiglio, Massimo Gregori, Raffaella Marchi, Lucio Torelli, Enrico Muzzi. Correlation of cochlear aperture stenosis with cochlear nerve deficiency in congenital unilateral hearing loss and prognostic relevance for cochlear implantation. Scientific Reports. 11 (1): 1. doi:10.1038/s41598-021-82818-9
- 4. ASHNR Webinars (available on Youtube) - extremely helpful and inspiring