The 4 basic types of hearing aids...

Behind-the-ear (BTE) aids have a plastic housing for the components which rests behind the ear. A clear plastic tube funnels amplified sound into an earmold in the ear canal. This model, though developed decades ago, can be every bit as sophisticated as smaller hearing aids. In fact, it can hold more circuitry and amplify sounds to a greater degree than in-the-ear types. BTE aids can be more durable than other types and a few are even waterproof.

In-the-ear (ITE) aids house componentry in a custom-formed earmold that fits within the outer portion of the ear. Its size and easy-to-use controls also may be helpful for those with limited manual dexterity.

In-the-canal (ITC) aids are smaller still, with an earmold that fits down into the ear canal, and a smaller portion facing out into the outer ear. They are discreet, yet still visible within the outer ear.

The newest generation of hearing aids are those that fit completely in the canal (CIC). Barely visible—and then only if someone’s peering into your ear—the only clue to their existence is the head of a tiny plastic line with which you place or remove the aid. CICs are popular for their aesthetic appeal, but the physiology of some individuals’ ears (i.e., a very narrow canal) may make this style unsuitable for them.

New technologies

Hearing aid technology has come a long way in the last few years, thanks to the computer microchip and digital circuitry. Here are some of the latest innovations.

Digital technology
Why does music from a cd sound more crisp, clear, and distortion-free than music from a record or tape? The answer, at least in part, is the difference between analog and digital sound processing.

Digital hearing aids have one or more microchip processors inside them that convert analog sound waves into the zeros and ones of computer language. Sound in this format can be processed more quickly and more efficiently than analog sound waves; in fact, incoming sounds are sampled at a rate of a million or more times per second. The digital aid’s circuitry analyzes these sound levels and frequencies, manipulating them to provide a more efficient match to an individual’s hearing profile.

For example, a person with hearing loss may have trouble hearing soft sounds, but when some sounds are amplified even a small amount, they become uncomfortably loud. Hearing aids with digital compression circuitry are able to stratify incoming sounds, detect those that need amplification from those that don’t, and process the sound accordingly.

Programmable technology
Digitally programmable hearing aids, which are different from fully digital aids in that they’re not equipped to process all incoming sound digitally, offer the very useful benefit of being able to sculpt sound to fit a particular individual’s unique hearing profile, and can be reprogrammed if there are changes in hearing loss. Programmable aids can be set up with multiple channels, enabling you to preset and store several different programs, each sculpted to a particular set of sound environments. You can then select the appropriate program using a button or remote control unit: normal conversation, concert hall, office, or telephone, for example.

Feedback reduction technology
Feedback has long been a problem for hearing aid wearers. Now we know a lot more about feedback, and have developed ways to deal with it. Feedback happens when amplified sound waves escape back out through the ear canal and are then re-amplified by the hearing aid—resulting in the high-pitched squeals that set your teeth on edge. Smaller, in-the-canal styles of hearing aids place components closer to the eardrum, preventing sound waves from escaping, thereby reducing, and often eliminating, feedback. Some new aids are also able to detect these sounds before they become audible and cancel them out, greatly reducing this frustrating problem.

How hearing aids are made

Hearing aids are not a standardized product; each aid has elements, including the shell or earmold, that are custom-made for the wearer. If you decide to try a hearing aid, the steps are quite simple. After the testing process, your hearing professional will make an impression of your ear, a relatively easy process.

A bit of cotton or foam is placed well into the ear canal to block any of the impression material from reaching the eardrum. Then the malleable impression material is placed in the ear until it sets, which takes a few minutes. Once it has conformed to the shape of your ear, it’s gently removed.

This impression or mold of your ear is sent, along with your audiogram and other test results, to the manufacturer’s lab. Hearing aids are individually constructed, beginning with the plastic housing or earmold, an exact replica of your ear impression. Circuitry is added, the aid is tested, and then shipped back to your hearing professional.

When the finished hearing aid is sent back, you’ll see your hearing professional for the fitting. This is likely to include repeating some of the audio testing you underwent initially, as well as tests that measure the hearing aid’s performance. As your hearing aid is fine-tuned, it’s a good time to ask questions, and talk through initial expectations with your hearing professional. You may need to come back a time or two for further adjusting, which is typical and usually covered in the purchase price of most hearing aids.

Provided by Starkey Labs