Bone Conduction Hearing Aids

Hearing aids work much like natural hearing, in that sound is taken from the environment then passed through the ear canal to the middle ear and amplified to the inner ear. Bone conduction hearing aids work to allow the person wearing it to hear, but in a different manner.

Bone conduction hearing aids work by taking sound from the environment, then with the use of an oscillator which vibrates against the skull, sends these vibrations to the inner ear and on to the hearing nerve to the brain where the vibrations are interpreted into sound.

Although regular hearing aids have more effect, bone conduction hearing aids are more useful for those who can not use the conventional hearing appliances. Persons with a malformed ear canal due to atresia, for instance, are unable to use the more common type of hearing aid, therefore the bone conduction hearing aid is a better choice for them.

What is Atresia?

Aural atresia is the lack of a fully developed ear canal, eardrum, middle ear space, and ear bones. Aural atresia is often due to a congenital deformity of the outer ear. Atresia may be unilateral (one ear) or bilateral (both ears). This is remedied by surgical repair, however not all people are good candidates for this type of surgery.

People who are plagued by repeated ear infections may not be candidates for certain hearing aids, may be interested in bone conduction hearing appliance. Ear canals that are blocked or too narrow may benefit from this type of device.

Bone conduction hearing aids are suitable for one sided hearing loss, children, and those with hearing loss that is not permanent. They are not widely used, but talking with your hearing specialist can give you more insight on this type of hearing aid.

The sound produced by a bone conduction hearing appliance is like that of the sound from a telephone, or mono sound instead of stereo sound, and does not give directional acuity. The person hears the sound, but is unable to determine where the sound is coming from.

A headband is utilized to hold the device in place, and can cause some discomfort due to the tightness of the headband. It is important that the device has good contact with the surface of the head for transmission of vibrations to be effective.

Initially, the bone conduction hearing aids were applied to thick-framed eye glasses for effective conduction of the vibrations. Today, the bone conduction hearing aids are surgically implanted, vibrating on the temporal bone. This successfully relieves the wearer of the irritation associated with the headband used to hold the appliance in place, as well as reducing distortion.

If you have one-sided hearing loss, or your ear canal is blocked or malformed, the bone conduction hearing aid may be the perfect solution.

by Barb Hicks, RN/LMT