Cochlear Implant Failure due to Cochlear Nerve Deficiency in a Child with Normal Internal Auditory Canal / 대한이비인후과학회지

ABSTRACT

The cochlear nerve, which propagates electrical signals to the auditory cortex, must function well for successful cochlear implantation. A narrow internal auditory canal (IAC) increases the risk of hypoplasia or aplasia of cochlear nerve, which may result in the failure of cochlear implantation. Therefore, a functioning cochlear nerve must be verified before deciding to do cochlear implantation by means of behavioral audiometry, electrophysiologic tests, or imaging studies in cases with narrow IAC. On the other hand, a candidate with a normal IAC can be overlooked in investigating the presence of functioning cochlear nerve. Because normal IAC does not always guarantee the presence of normal cochlear nerve, the functioning cochlear nerve should be proved prior to cochlear implantation in those cases. We report on a child, who had normal IAC and cochlea but failed auditory stimulation after cochlear implantation, and who was diagnosed as having cochlear nerve deficiency through retrospective review.