If your auditory (hearing) nerve isn’t working, hearing aids or a cochlear implant won’t help. But an auditory brainstem implant that directly stimulates the auditory brainstem may be beneficial.
Auditory brainstem implants (ABIs) are still relatively near technology. They work by bypassing the ear and auditory nerve and stimulating the auditory brainstem directly to provide a sensation of hearing.
Why an might auditory brainstem implant help
ABIs are mostly used by adults who’s auditory nerve has been damaged, or children born without a working auditory nerve.
If the auditory nerve does not work, it cannot send information from the ear up to the brain. Hearing aids and cochlear implants which rely on a working auditory nerve do not help in this case.
An ABI can bypass the missing or damaged auditory nerve and stimulate part of the area at the base of the brain responsible for hearing directly (the auditory brainstem).
How an auditory brainstem implant works
An ABI has several different parts, some of which are external (worn on the body) and some of which are internal (cannot be seen):
- the external part consists of a microphone and a speech processor (which either sit behind your ears or are body-worn), a lead and a transmitter coil.
- the internal part includes a receiver and a number of electrodes that directly stimulate your brainstem to provide a sensation of hearing. It’s surgically implanted directly on to your brainstem. It therefore bypasses the inner ear and auditory nerve.
What to expect from an auditory brainstem implant
A few weeks after the operation to insert the internal part, the external parts are fitted, and your implant is switched on. The speech processor is tuned over several appointments to meet your needs. Following implantation, long-term support from professionals is crucial to help you to learn to listen to and understand the new signals from your implant.
The results of the operation vary from person to person. ABIs may give you some sensation of hearing.
Who can benefit from an auditory brainstem implant
ABIs are suitable for only a small group of people for who hearing aids and cochlear implants are not effective.
ABIs have been used for adults who have damaged their auditory nerve, or who have Neurofibromatosis Type 11 (NF2). NF2 is a condition which causes tumours to grow on the hearing nerves. If the auditory nerve has been damaged, hearing aids and cochlear implants are not helpful because sound information can’t be transferred from the ear to the brain along the nerve.
To find out more about auditory brainstem implants, see the National Institute of Clinical Excellence (NICE) guidelines for auditory brainstem implants.