Management of Cochlear Nerve Hypoplasia and Aplasia.

Management of Cochlear Nerve Hypoplasia and Aplasia. Adv Otorhinolaryngol. 2018;81:81-92 Authors: Freeman SR, Sennaroglu L Abstract Approximately 2% of congenital profound deafness cases are due to cochlear nerve (CN) deficiency. MRI is essential to confirm if the nerve is deficient, but because of limitations with resolution, especially when the internal auditory canal is narrowed, it is often unable to distinguish between hypoplasia and aplasia. A full audiometric test battery should always be performed, even if the MRI suggests CN aplasia, as there will sometimes be evidence of audition. Electrically evoked auditory brainstem response testing can be carried out transtympanically via the round window or using an intracochlear test electrode to help determine the status of the CN. If any test suggests the presence of a CN, then cochlear implantation (CI) should be considered. Children should be followed up closely with audiometric, electrophysiological and language assessments to determine the benefits. They may initially show benefit but fail to progress. CI results are variable and often result in poor outcomes with Categories of Auditory Perception scores of <5. Auditory brainstem implantation (ABI) can be considered when CI is contraindicated or fails to provide adequate benefit. This may provide better outcomes, but this form of surgery has greater risks and future device replacement (in case of device failure) may be compli...
Source: Advances in Oto-Rhino-Laryngology - Category: ENT & OMF Tags: Adv Otorhinolaryngol Source Type: research