An Auditory Brainstem Implant (ABI) is an implant like a cochlear implant except that it bypasses the cochlea altogether and attaches its electrode directly to the base of the brain. Only a few specially authorized medical centers and clinics are authorized to implant ABIs.
Most of the recipients have reported being able to hear sounds that can help
them lip read, but most are not able to discriminate speech from these sounds
alone. Candidates for this experimental implant are carefully chosen. The surgery
is much more invasive than the surgery required for a cochlear implant and is usually undertaken only in situations where the patient is (or has become) completely deaf. Many candidates for the ABI trials are NF2 patients having their second tumor removed.