Hi guys... I would like to share my knowledge about Auditory Brainstem Implants. This is a novice topic for both professionals and also for patients. There are very few blogs on this topic, so I have decided to blog on this topic. In my first post, i am just introducing the term and its necessity.
Auditory Brainstem Implants
The Auditory Brainstem Implant (ABI) is a prosthetic device intended to restore some degree of hearing function to persons deafened by bilateral vestibular schwannomas (tumors on both balance nerves). The ABI is the first device specifically designed to bypass the cochlea and the auditory nerve to transmit sound directly to the brainstem. The ABI is placed directly on the nerve center (cochlear nucleus) at the base of the brain, typically during surgery to remove tumors. The surgeon makes an incision in the skin of the side of the head, and removes some of the bone behind the ear. This exposes the tumour so that it can be removed and also allows access to the brain stem beneath it. Sometimes the surgeon approaches the brain stem through the back of the head.
In people with vestibulocochlear nerve damage, hearing is not improved by hearing aids or cochlear implants. The ABI is designed primarily for patients suffering from Neurofibromatosis Type II (NF2), a hereditary disease that can cause profound hearing loss through the growth of bilateral tumors on the balance nerves. Because the balance nerves are adjacent to the auditory (and facial) nerves, tumor removal typically necessitates severing the auditory nerve. A cochlear implant cannot be used for these patients because the auditory nerve, once severed, is not able to carry signals from the cochlea to the cochlear nucleus in the brainstem.
Most ABI recipients benefit from the device through increased sound awareness. Because a very few ABI recipients are able to understand speech without lip reading, the level of performance achieved with ABI is poorer than that obtained by people with a cochlear implant (CI). However, the environmental and speech sounds that patients receive through the ABI help significantly to improve their communication and quality of life. ABI sound is most beneficial when it can be combined with lip-reading cues.
In people with vestibulocochlear nerve damage, hearing is not improved by hearing aids or cochlear implants. The ABI is designed primarily for patients suffering from Neurofibromatosis Type II (NF2), a hereditary disease that can cause profound hearing loss through the growth of bilateral tumors on the balance nerves. Because the balance nerves are adjacent to the auditory (and facial) nerves, tumor removal typically necessitates severing the auditory nerve. A cochlear implant cannot be used for these patients because the auditory nerve, once severed, is not able to carry signals from the cochlea to the cochlear nucleus in the brainstem.
Most ABI recipients benefit from the device through increased sound awareness. Because a very few ABI recipients are able to understand speech without lip reading, the level of performance achieved with ABI is poorer than that obtained by people with a cochlear implant (CI). However, the environmental and speech sounds that patients receive through the ABI help significantly to improve their communication and quality of life. ABI sound is most beneficial when it can be combined with lip-reading cues.
