On this page:
- What are hearing aids?
- What are the styles of hearing aids?
- What is the difference between analog and digital hearing aids?
- What are some hearing aid features?
Hearing aids are sound-amplifying devices designed to help people who have hearing loss. Most hearing aids share several similar electronic components:
- 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.
- Batteries that power the electronic parts.
Hearing aids differ by design, technology used to achieve amplification (analog or digital), and features such as wireless connectivity and software applications.
Some hearing aids also have earmolds or earpieces to direct the flow of sound into the ear and enhance sound quality. Hearing aid selection is based on the type and severity of hearing loss, listening needs, and lifestyle.
Behind-the-ear (BTE) aids have most parts 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 a child grows. Also, BTE aids are easy to clean and handle, and are relatively sturdy.
"Mini" BTE, or receiver in canal (RIC) aids are a type of BTE aid that fits behind the ear, but is typically smaller in size. A narrow tube is used to connect the aid to the ear canal. Mini BTEs may have a smaller earpiece for insertion, but may also use a traditional earmold. These earpieces may reduce the occlusion effect in the ear canal—a plugged up sensation that causes a hearing aid user’s voice to sound louder inside the head—and increase comfort, reduce feedback, and address cosmetic concerns for many users.
In-the-ear (ITE) aids have all parts of the hearing aid 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, and may be easier to handle than smaller aids.
In-the-canal (ITC) aids and completely-in-the-canal (CIC) aids are 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.
Analog hearing aids are less common. They make continuous sound waves louder by amplifying all sounds (speech and noise) in the same way. Some analog hearing aids have a microchip to store multiple program settings used in different listening environments, such as in a quiet place (library) or in a noisy place (restaurant or soccer field). As the listening environment changes, the hearing aid settings may be changed by pushing a button on the hearing aid.
Digital hearing aids are more common. They have all the features of analog programmable aids, but they convert sound waves into digital signals and produce an exact duplication of sound. Microchips in digital hearing aids analyze speech and other environmental sounds and store multiple program settings. The digital hearing aids allow for more complex sound processing during the amplification process which may improve performance in certain situations, such as background noise and whistle reduction. They also have greater flexibility in hearing aid programming so the sound they transmit can be matched to the needs for a specific pattern of hearing loss.
Hearing aids may have features that help in different communication situations, such as,
- Directional microphone may help you speak in noisy environments. They amplify sound coming from a specific direction to a greater level than sound from other directions. When the directional microphone is activated, sound in front of you (face-to-face conversation) is amplified to a greater level than sound from behind you.
- Noise Reduction reduces the levels of background noise compared to the sounds you are trying to hear.
- Feedback suppression helps prevent the hearing aid from producing an uncomfortable squealing sound.
- T-coil (Telephone switch) allows you to switch from the normal microphone setting to a T-coil setting to hear better on the telephone. All wired telephones must be hearing aid compatible. In the T-coil setting, environmental sounds are removed 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. A speaker’s voice, who may be far away, is amplified significantly more than any background noise. Some hearing aids have a combination M (microphone) and T (telephone) switch, so while listening with an induction loop, you can still hear nearby conversations.
- Wireless connectivity can allow a hearing aid to receive streamed audio (e.g., music, phone calls) and allow the user to adjust the hearing aid settings.
- Direct audio input allows you to plug in a remote microphone or an FM assistive listening system, connect directly to a television, or connect to other devices such as your computer or radio.
The more complicated features may allow the hearing aids to best meet your particular pattern of hearing loss and may improve performance in specific listening situations. However, these sophisticated electronics may increase the cost of the hearing aid.