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Hearing Aids

What You Need to Know

What are Hearing Aids?

Hearing aids are sound-amplifying devices designed to aid people who have a hearing impairment.

Most hearing aids share several similar electronic components, including a microphone that picks up sound; amplifier circuitry that makes the sound louder; a miniature loudspeaker (receiver) that delivers the amplified sound into the ear canal; and batteries that power the electronic parts.

Hearing aids differ by design, technology used to achieve amplification (i.e., analog vs. digital) and special features.

Some hearing aids also have earmolds or earpieces to direct the flow of sound into the ear and enhance sound quality. The selection of hearing aids is based on the type and severity of hearing loss, listening needs, and lifestyle.

What are the Different Styles of Hearing Aids?

Behind-the-Ear (BTE) Aids

Most parts are contained in a small plastic case that rests behind the ear; the case is connected to an earmold or an earpiece by a piece of clear tubing. This style is often chosen for young children because it can accommodate various earmold types, which need to be replaced as the child grows. Also, the BTE aids are easy to be cleaned and handled, and are relatively sturdy.

"Mini" BTE (or "On-the-Ear") Aids

A new type of BTE aid called the mini BTE (or "on-the-ear") aid. It also fits behind/on the ear, but is smaller. A very thin, almost invisible tube is used to connect the aid to the ear canal. Mini BTEs may have a comfortable ear piece for insertion ("open fit"), but may also use a traditional earmold. Mini BTEs allow not only reduced occlusion or "plugged up" sensations in the ear canal, but also increase comfort, reduce feedback and address cosmetic concerns for many users.

In-the-Ear (ITE) Aids

All parts of the hearing aid are contained in a shell that fills in the outer part of the ear. The ITE aids are larger than the in-the-canal and completely-in-the-canal aids (see below), and for some people may be easier to handle than smaller aids.

In-the-Canal (ITC) Aids and Completely-in-the-Canal (CIC) Aids

These hearing aids are contained in tiny cases that fit partly or completely into the ear canal. They are the smallest hearing aids available and offer cosmetic and some listening advantages. However, their small size may make them difficult to handle and adjust for some people.

What are the Different Styles of Hearing Aids?

Analog Hearing Aids

Analog hearing aids make continuous sound waves louder. These hearing aids essentially amplify all sounds (e.g., speech and noise) in the same way. Some analog hearing aids are programmable. They have a microchip which allows the aid to have settings programmed for different listening environments, such as in a quiet place, like at a library, or in a noisy place like in a restaurant, or in a large area like a soccer field. The analog programmable hearing aids can store multiple programs for the various environments.

As the listening environment changes, hearing aid settings may be changed by pushing a button on the hearing aid. Analog hearing aids are becoming less common.

Digital Hearing Aids

Digital hearing aids have all the features of analog programmable aids, but they convert sound waves into digital signals and produce an exact duplication of sound. Computer chips in digital hearing aids analyze speech and other environmental sounds. The digital hearing aids allow for more complex processing of sound during the amplification process which may improve their performance in certain situations (for example, background noise and whistle reduction). They also have greater flexibility in hearing aid programming so that the sound they transmit can be matched to the needs for a specific pattern of hearing loss. Digital hearing aids also provide multiple program memories. Most individuals who seek hearing help are offered a choice of only digital technology these days.

What are Some Features for Hearing Aids?

Hearing aids have optional features that can be built in to assist in different communication situations.

Directional Microphone
Directional microphone may help you converse in noisy environments. Specifically, it allows sound coming from a specific direction to be amplified to a greater level compared to sound from other directions. When the directional microphone is activated, sound coming from in front of you (as during a face-to-face conversation) is amplified to a greater level than sound from behind you.

T-Coil (Telephone Switch)
T-coil (Telephone switch) allows you to switch from the normal microphone setting to a "T-coil" setting in order to hear better on the telephone. All wired telephones produced today must be hearing aid compatible. In the "T-coil" setting, environmental sounds are eliminated, and sound is picked up from the telephone. This also turns off the microphone on your hearing aid so you can talk without your hearing aid "whistling."

The T-coil works well in theaters, auditoriums, houses of worship, and other places that have an induction loop or FM installation. The voice of the speaker, who can be some distance away, is amplified significantly more than any background noise. Some hearing aids have a combination "M" (Microphone) / "T" (Telephone) switch so that, while listening with an induction loop, you can still hear nearby conversation.

Direct Audio Input
Direct audio input allows you to plug in a remote microphone or an FM assistive listening system, connect directly to a TV, or connect to other devices such as your computer, a CD player, tape player, radio, etc.

Feedback Suppression
Feedback suppression helps suppress squeals when a hearing aid gets too close to the phone or has a loose-fitting earmold.

Hearing Aids and Cell Phones

What is that buzzing noise in my cell phone?

People who wear hearing aids or have implanted hearing devices may experience some difficulties when trying to use cell phones. That buzzing noise you hear is interference due to radiofrequency (RF) emissions from your phone. RF interference does not occur for all combinations of digital wireless telephones and hearing aids. However, when interference does occur, the buzzing sound can make understanding speech difficult, communication over cell phones annoying, and, in the worst case, render the cell phone unusable for the hearing aid user.

Fortunately, the compatibility of cell phones and hearing aids is improving. Some cell phones have lower radiofrequency emissions or use different technologies that can reduce the unwanted effects on hearing aids.

What should I look for in a cell phone?

Rules set by the Federal Communications Commission (FCC) make it easier for you to choose a cell phone right for you. The FCC requires cell phone manufacturers to test and rate their wireless handsets' hearing aid compatibility using the American National Standards Institute (ANSI) C63.19 standard. These ratings give an indication of the likelihood that a cell phone may interfere with hearing aids; the higher the rating, the less likely the cell phone-hearing aid combination will experience undesired interference.

Labeling on the outside packaging of cell phones will tell you if they are hearing aid compatible (HAC). Hearing aid users should read and understand these ratings when choosing a cell phone.

What do these ratings mean?

Cell phones that are rated “good” or “excellent” for use with hearing aids set in microphone (M) mode will have a rating of M3 or M4. The higher the “M” rating, the less likely you will experience interference when the hearing aid is set in the microphone mode while using the cell phone.

Cell phones are also rated with hearing aids or cochlear implants that have a T-coil. Those rated “good” or “excellent” for use with hearing aids set in T-coil mode will have a rating of T3 or T4. The higher the “T” rating, the less likely you will experience interference when the hearing aid is set in the T-coil mode while using the cell phone.

Hearing aid manufacturers use a similar rating system. The hearing aid ratings and the cell phone ratings can be combined to help identify combinations that will provide you with a positive experience. So, a hearing aid rated M2 and a wireless device rated M3 with a combined rating of 5 and would likely provide “normal” use. A ratings combination of 6 would likely provide “excellent performance”. Every individual's hearing aid technology and settings are unique; therefore, these ratings do not guarantee performance.

Because these HAC ratings do not guarantee performance, you should “try before you buy” any wireless device if possible. You should try different brands and models to see which phone works best for you. Also, be sure to closely examine the return policy for the device and the service provider's policy on early termination of contracts before signing up for service.

The more complicated features may allow the hearing aids to best meet your particular pattern of hearing loss. They may improve their performance in specific listening situations; however, these sophisticated electronics may significantly add to the cost of the hearing aid as well.

SOURCE:

The U.S. Food and Drug Administration



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