Dr. Gregory Lowe, Audiologist, Types of Hearing Aids

Different Types of Hearing Aids

Currently, there are basically four types of hearing aids that are used. These include the completely-in-the-canal aid, the canal aid, the in-the-ear aid, and the behind-the-ear aid. There are two other styles that are used much less frequently at this point in time. These include the body hearing aid, and the eyeglass hearing aid. Digitally programmable circuits, and totally digital circuits are available in most styles. Each of these types of aids will be discussed.

BEHIND-THE EAR HEARING AIDS

The BEHIND-THE-EAR aid hangs behind the ear and is coupled to a custom fitted ear mold that fits in the ear. The ear mold is the part of the system that delivers the amplified sound from the hearing aid into the ear canal. Behind-the-ear aids are not as popular as they were several years ago. However, they do offer a few advantages for individuals with severe hearing loss. First, the hearing aid can be worn on either the right or left ear if a person has two ear molds.

The ear mold can be easily removed and replaced whenever necessary. If the hearing loss is the same in each ear, being able to alternate ears can be useful. For example, when driving in a car, the driver would probably want the aid on the right ear to hear the passenger. If the hearing impaired person is the passenger, then the aid could be worn on the left ear to help in hearing the driver. Another advantage is that if the hearing aid malfunctions and needs to be returned to the manufacturer, then a loaner aid could be provided by attaching it to your custom ear mold. This would allow you to hear while your aid was being repaired. A third advantage is that patients with a severe loss can usually obtain more volume from the behind-the-ear hearing aid without the annoying feedback (whistle) many hearing aid users experience. The feedback occurs because the amplified sound delivered to the ear canal leaks out around the ear mold and enters the microphone of the hearing aid. With a behind-the-ear aid, the microphone is farther away from the ear canal than with the in-the-ear or canal aid. The behind-the-ear aid may be less noticeable than the other aids because the aid fits behind the ear and can be covered with hair. The ear mold that fits in the ear is usually clear acrylic and is much less noticeable than the in-the-ear hearing aid that is not clear. Finally, ear wax can cause problems with all types of hearing aids. If the wax plugs the hole in the ear mold where the sound comes out, then the patient will not hear well with the aid. With the behind-the-ear aid, the ear mold can be detached from the aid for cleaning. The mold can then be soaked in water, blown out with an air hose, cleaned out with a wire or pipe cleaner, and then washed with a mild soap without damaging the components within the hearing aid. A plugged ear mold is one of the most common problems for hearing aid users.

IN-THE-EAR HEARING AIDS

The IN-THE-EAR aids fit entirely in the ear, and are the most popular aids we fit. There is nothing behind the ear. The in-the-ear aid is sometimes easier to insert since there is only one part to manipulate. This type of aid is good for patients with very little room behind their ears either because they have small ears, or because they wear glasses, or wear glasses in combination with a wig. However, the in-the-ear aid is usually not recommended for patients with a severe hearing loss since people with that degree of loss require substantial gain from the hearing aid. Since the microphone is so close to the ear canal, feedback (whistle) may occur. If the aid fits tightly, feedback may not be a problem. The presence of ear wax is another problem. The wax can be easily pushed into the aid when it is inserted into the ear, or it may be pushed further into the aid when the patient attempts to clean it out. This often damages the receiver (speaker) inside the aid. However, proper cleaning of the aid can help to alleviate this problem. Most new aids have a wax guard to help prevent wax from entering the aid.

IN-THE-CANAL HEARING AIDS

One of the smallest aids to be introduced is the CANAL aid. This aid has received much public attention since President Reagan was fit with two aids several years ago. The canal aid fits within the ear canal only. It does not fill in the outer portion of the ear like the in-the-ear aid. Since it is so much smaller than any of the other aids, it uses the smallest hearing aid battery available. The life of one battery in the canal aid is about two weeks if the aid is used ten hours a day. It is not recommended for patients with poor manual dexterity, or with a severe hearing loss. The problems of acoustic feedback (whistle) are just as greater even greater than with the in-the-ear hearing aid.

COMPLETELY-IN-THE-CANAL

The COMPLETELY-IN-THE-CANAL aid is the smallest hearing aid available. It is virtually invisible when worn. It has the advantage of a more natural placement for the hearing aid microphone. It uses the sound gathering capabilities of the outer ear. There is also less wind noise since the microphone is deeper in the ear canal. Feedback when using the telephone is normally eliminated. However, the patient must have an ear canal large enough to comfortably accept an aid that fits deep in the canal.

BODY HEARING AIDS

The BODY AID is probably the most easily noticed hearing aid. The body aid is usually worn in a shirt pocket or under the shirt. A wire then sends the amplified signal from the hearing aid to the receiver that attaches to the ear mold. These aids are not used as much now as they were in the past because of the development of extremely powerful behind-the-ear aids. There are still some hearing impaired individuals who have such a severe loss that even the new power behind-the-ear aids are not strong enough. Body aids are also used with infants. The body aid is harder to lose since it can be strapped to the baby. The ears of most infants are not large enough to support a behind-the-ear aid, and their ears are growing too rapidly to fit an in-the-ear aid that would maintain a good fit. The volume controls of body aids are also easier for the parents or therapists to control. There are also many geriatric patients who simply cannot manipulate the controls on any of the smaller aids.

EYEGLASS HEARING AIDS

With the introduction of the in-the-ear and the canal hearing aids, and with the miniaturization of the behind-the-ear hearing aids, the EYEGLASS hearing aid has become almost obsolete. One of the disadvantages of the eyeglass aid is that if either the hearing aid or the glasses breaks, the patient has to get along without both for some period of time. However, in cases where a patient does not have much room behind their ears because of the presence of their glasses, the eyeglass aid is an alternative.

Four Most Popular Styles

R. Gregory Lowe, Ph.D., P.C. Audiologist

Personalized Hearing Care