Hearing Loss

Hearing Aids

There are many types of hearing aids, which vary in size, power and circuitry. Among the different sizes and models are:

Body worn aids

This was the first type of hearing aid, and thanks to developments in technology they are now rarely used. These aids consist of a case containing the components of amplification and an ear mold connected to the case by a cord. The case is about the size of a pack of cards and is worn in the pocket or on a belt. Because of their large size, body worn aids are capable of large amounts of amplification and were once used for profound hearing losses. Today, they have largely been replaced by BTEs.

Behind the ear aids (BTE)

BTE aids have a small case that fits behind the ear and conducts sound to the ear through an earmold that is custom made. BTEs can be used for mild to profound hearing losses and are especially useful for children because of their durability and they can easily connect to assistive listening devices such as FM systems for classroom use. BTEs can range from very inconspicuous skin tones to cheerful colors depending on the users preference. Recent innovations in BTEs include miniature "invisible" BTEs with thin hair like sound tubes (see open-fit devices below). These are often less visible than ITEs and some keep the ear canal more open, so listeners may still utilize their residual natural hearing (most helpful for those with normal hearing in the lower frequencies). Ideal for high frequency losses, these miniature versions are generally used for mild to moderate hearing loss.

In the ear aids (ITE)

These devices fit in the outer ear bowl (called the concha); they are sometimes visible when standing face to face with someone. ITE hearing aids are custom made to fit each individual's ear. They can be used in mild to some severe hearing losses. Feedback, a squealing/whistling caused by sound leaking out of the aid and being amplified again, may be a problem for severe hearing losses. Some modern circuits are able to provide feedback regulation or cancellation to assist with this. ITEs are not recommended for young children because their fit cannot be as easily modified as the earmold for a BTE, and the aid must then be replaced frequently as the child grows. By the time a person is 13-16 years old, s/he will probably be able to wear an ITE if it is appropriate for the hearing loss found.

In the canal (ITC), mostly in canal (MIC) and completely in the canal aids (CIC)

ITC aids are smaller, filling only the bottom half of the external ear. You usually cannot see very much of this hearing aid when you are face to face with someone. MIC and CIC aids are even smaller and often not visible unless you look directly into the wearer's ear. They can be used for mild and sometimes moderate losses. CICs are not recommended if you have very good low frequency hearing as the complete plugged up effect may make your voice resonate in your head even if you have them switched off (the "occlusion effect").

Open-fit devices

Recently a new device has come on the market, the "Open-fit" or "Over-the-Ear" OTE Hearing Aid. Usually quite discreet, these are small Behind-the-ear type devices, with a much finer clear tube that runs down into the ear canal. Inside the ear canal, there is a small soft silicone dome or a molded, highly vented acrylic tip that holds the tube in place. There are also devices available which have an external speaker, placed inside the ear canal, and connected to the hearing system itself by a thin cable. The external speaker allows the device behind the ear to be even smaller. These devices are designed to reduce the "occlusion effect", which is the amplification of your own voice when your ears are plugged up (try sticking your fingers in your ears and talking). Open-fit devices are very beneficial for High-Frequency hearing losses, and have been introduced by all major hearing aid companies.

This article is licensed under the GNU Free Documentation License.

It uses material from the Wikipedia article "Hearing Aid"