How Hearing Aids Work

You may have heard a lot about hearing aids (pun intended!) but aren’t quite sure how they work. That’s understandable, especially since the various types of hearing aids can operate differently. At the most basic level, a hearing aid uses a microphone, amplifier, and speaker to help its wearer hear better.

• A microphone collects sounds from the wearer’s environment.
• These sound vibrations are converted into electrical signals or numerical codes.
• The signals or codes go to the amplifier.
• The amplifier magnifies the signals or codes (like making sounds louder).
• The signals or codes travel from the amplifier to the ear through a speaker.
• Auditory hair cells pick up the signals or codes, convert them to neural signals and transmit them to the brain.

These processes happen nearly instantaneously with no noticeable delay. Some aids have features such as a telecoil to cut out background noise, making listening on the telephone, watching TV and listening to music much easier. You can pair telecoil functionality with assistive listening devices to stream music, TV and more. What if you want some background noise, though? No problem. A setting such as “MT” activates both the microphone and the telecoil.

The Role of Amplification

Hearing aids hugely benefit people who have mild to moderate levels of hearing loss. People with severe to profound levels may benefit more from avenues such as cochlear implants.

In any case, people who wear hearing aids have damage to their auditory hair cells. Lower-level damage means that less amplification is needed. If a person’s inner ear is too damaged, hearing aids might not help at all.

Hearing aids put surviving, undamaged hair cells to work. These cells receive the sounds that have been converted into electrical signals or numerical codes and send them to the brain. Amplification is what hearing aids are all about: They make sounds louder to compensate as much as possible for the number of damaged hair cells. An audiologist can evaluate you for hearing loss and determine if you would benefit from hearing aids nearby.

Hearing Aid Capabilities

Depending on the type of hearing aid, it may have these features:

• Personalized volume control so users can increase or decrease sound volume as they wish
• Noise cancellation, wind reduction and/or other environmental controls
• Directional microphones so users can hear better in situations with background noise
• Direct audio input for streaming from TVs, cellphones, computers and music devices
• Rechargeable batteries
• Synchronization for wearers with two hearing aids (changes to one aid automatically carry over to the other aid)
• Programs for different listening environments and listening needs

Various Styles of Hearing Aids

Hearing aids come in digital or analog form. Most newer versions are digital, with sound vibrations converted into numeric codes. Analog hearing aids convert sound into electrical signals.

With digital hearing aids, audiologists can fine-tune which frequencies the aids amplify and by how much. There’s a lot more room for customization than there is with analog hearing aids. As for the aids themselves, they may be canal, behind-the-ear or in-the-ear.

Canal aids (for people with mild to moderately severe loss): These hearing aids fit in the ear canal. Their small size limits how powerful they are and the number of features possible, so they are not ideal for people with severe to profound loss. For example, telecoil options are not available. Canal hearing aids come in two forms: in the canal (ITC) and completely in the canal (CTC).

Behind-the-ear (for all types of hearing loss): People with severe to profound hearing loss can wear BTE aids, as can folks with mild to moderate loss. Because of BTE visibility, though, some people with mild to moderate loss prefer to wear another type of hearing aid. Fortunately, there are newer mini-BTEs that are much more discreet than regular-sized BTEs. Behind-the-ear aids have room for many, many features.

In-the-ear (for mild to severe loss): This type of hearing aid fits in the outer ear. Some versions have room for features such as a telecoil, making it easier for wearers to talk on the telephone, watch TV and listen to music. They can also take advantage of the induction loop systems common in airports, school and university classrooms, concert halls, museums and auditoriums.

You should be able to find all three types of hearing aids nearby.

One Hearing Aid Versus Two

If you need two hearing aids, it’s better to get two rather than try to get by wearing just one. Two hearing aids let you better pinpoint where sounds come from (directionality). They allow for more natural hearing and for enhanced speech understanding.

The Advantages of Hearing Aids

Hearing aids are a huge asset for people with varying levels of hearing loss. They enable folks to participate fully (or more fully) in daily life. Formerly tricky activities such as listening to music and following conversations in noisy environments can become much easier.