House's original ABI consisted of two ball electrodes that were implanted near the surface of the cochlear nucleus on the brainstem.
[6] NF2 generally presents in adolescence or young adulthood, so candidacy was previously limited to patients aged 15 years or older, with NF2 and bilateral non-functioning auditory nerves.
[6] In Europe and other countries, ABI is CE-marked and approved for patients 12 months and older who cannot benefit from a cochlear implant due to non-functional auditory nerves.
[3] A handful of medical centres, including New York University, are undergoing feasibility studies in the pediatric population.
It is normally performed by both a neurosurgeon and an ENT surgeon together, who insert the electrode array through the fourth ventricle onto the surface of the cochlear nucleus.
[3] For patients with NF2, the surgeon will spend a significant amount of time removing the acoustic neuroma tumours before inserting the implant.
[3] Speech perception outcomes with an ABI are generally poorer than those reported in cochlear implant multichannel CI users.
[7] A study by Colletti found that a significant number of patients without NF2 were able to understand speech with an ABI, including effortless telephone use.
[8] It is believed that the tumours caused by the NF2 damage specialised cells in the cochlear nucleus important for speech perception.