Hearing Restoration for Acoustic Neuroma
Acoustic neuroma may cause hearing loss. This can happen in one ear because of a tumor that arises in the eighth cranial nerve—which conveys information from the inner ear to the brain—or from treatment. Losing hearing in one ear can make it hard to understand speech when there’s a lot of background noise or to identify the direction a sound is coming from.
Doctors at NYU Langone offer several options for hearing enhancement or preservation.
Contralateral Routing of Offside Signals Hearing Aid
Doctors at NYU Langone may prescribe a contralateral routing of offside signals, or CROS, hearing aid for people with acoustic neuroma who have lost hearing in one ear and have good hearing in the other.
These hearing aids often consist of two parts: a microphone or transmitter worn in the hearing impaired ear that picks up and transmits sound to a receiver worn in the hearing ear. The transmission takes place through a wire or a wireless system. These hearing aids come in various sizes, shapes, and models and can be worn in the ear or behind the ear.
Another type is the TRANSEAR hearing aid, which uses the bones of the skull to conduct sound and consists of a single device that fits into the hearing impaired ear. The device contains a microphone that receives sound and converts it into vibrations that travel through bones in the ear canal and into the skull. The vibrations move over the skull bones to the hearing ear, where they are picked up by the cochlea, the part of the inner ear that processes sound.
An NYU Langone audiologist can fit you with a hearing aid, demonstrate how it works, and provide follow-up counseling on how to get the most out of the device.
Bone-Anchored Hearing Aid
A bone-anchored hearing aid, or BAHA, is a device that conducts sound directly to the cochlea using the skull, bypassing the other portions of the ear.
This type of hearing aid consists of a small titanium screw. In an outpatient procedure using local anesthesia, a surgeon places the screw in the skull behind the non-hearing ear. The screw is left alone as it integrates with, or becomes part of, the skull bone, a process that takes about three months. Afterward, a surgeon attaches a sound processor to the screw behind the non-hearing ear. The processor picks up sound and transmits vibrations through the titanium screw to the skull. These vibrations travel over the skull to the cochlea of the hearing ear.
Newer bone-anchored hearing aid models use a magnet placed under the skin, instead of a screw, to keep the processor in place.
A cochlear implant, available at NYU Langone’s Cochlear Implant Center, is a surgically implanted device that provides people with direct electrical stimulation of the auditory nerve to help restore hearing and suppress tinnitus. A cochlear implant can be used after acoustic neuroma surgery if the cochlear nerve is still intact and functional but hearing has been lost due to damage to the tiny hair cells in the cochlea.
Doctors surgically place a receiver and stimulator on the bone of the skull under the skin, behind the ear. An electrode attached to this device is implanted in the cochlea to provide electrical stimulation to the auditory nerves. The person wears an external processor behind the ear that communicates with the internal device.
Cochlear implants work by completely bypassing the injured cochlea. The external part of the device contains a microphone and speech processor, which gather and sort sounds from the environment and transmit them to an internal receiver and stimulator.
This receiver converts sound into electronic impulses, then sends these impulses through a series of electrodes that delivers them to the auditory nerve. The brain interprets the electronic impulses as speech or other sounds. In this way a cochlear implant allows you to hear.
Auditory Brainstem Implant
An auditory brainstem implant (ABI) is a device, similar to a cochlear implant, that can be used to restore a degree of hearing. This device is used most often for people with neurofibromatosis type 2, a genetic disorder that causes tumors of the nervous system. Often, these tumors can grow on both auditory nerves, causing near complete hearing loss.
In an ABI, a paddle electrode is placed in the auditory brainstem. This directly stimulates the auditory pathways and bypasses the damaged auditory nerves to help you hear. An ABI does not completely restore normal hearing, but is a good alternative for those who cannot use a hearing aid or cochlear implant.