An auditory brainstem implant (ABI) is a small device that is surgically implanted in the brain of a deaf person whose auditory nerves are lacking or damaged. The auditory nerves conduct the sound signals from the ear to the brain. The implant enables otherwise deaf people to have a sensation of hearing.
The hearing sensation is limited, but the implant recipients are relieved of total sound isolation, facilitating lip-reading.
The auditory brainstem implant consists of a small electrode applied to the brainstem, a small microphone on the outer ear, and a speech processor. The electrode stimulates vital acoustic nerves by means of electrical signals and the speech processor digitally transmits the sound signals to a decoding chip placed under the skin. A small wire connects the chip to the implanted electrode attached to the brainstem. Depending on the sounds, the electrode delivers different stimuli to the brainstem making deaf people hear a variety of sounds.
Users of auditory brainstem implant
Typically, people who have an auditory brainstem implant suffer from neurofibromatosis Type 2, a disease generating tumors in the brain. Auditory nerve damage may result from the removal of the bilateral acoustic tumors.
Due to the brain surgery required for the implantation and the limited effectiveness of the implant, the number of implant recipients is small.