The Cochlear Implant provides many individuals who receive no benefit from hearing aids the ability to hear. It requires the presence of a functioning auditory nerve for success. However, there are medical conditions that affect the auditory nerve, making the cochlear implant a less likely option to regain hearing. In the U.S., the auditory brainstem implant (ABI) may be an option. The ABI is implanted beyond the auditory nerve.
The most important FDA indications for its use in the U.S. are the diagnosis of neurofibromatosis type 2 (NF2) and be at least 12 years old. NF2 is a genetic condition in which affected individuals develop bilateral vestibular schwannomas (tumors) which, over time, lead to bilateral profound hearing loss. Over time the tumors may become life-threatening and require surgical removal. While an individual may, in some cases have usable hearing prior to surgery, the surgery usually results in profound hearing loss. The surgery involves risk, therefore, the ABI is implanted at the time of tumor removal.
The first Auditory Brainstem Implant was performed by Drs. William House and William Hitselberger at the House Ear Institute in Los Angeles, after removal of an acoustic neuroma in 1979. It consisted of a simple ball-type electrode. The first multichannel ABI was implanted in Europe by Drs. Roland Laszig and Peter Sollmann in 1992 and in 2000 the FDA approved the Nucleus multichannel ABI device for implantation in the U.S.
Although ABI recipients in general do not receive the same level of success as a cochlear implant recipient, some do well enough to follow conversations with visual cues and in some cases even the ability to use a telephone. The ABI is an option worth consideration for with neurofibromatosis type 2 who are contemplating surgery for tumor removal. The rehabilitation involved after the surgery can be slow and long term. Realistic expectations, a strong support group, and motivation are very important for the best possible outcome.
