How Hearing Aids Work

Hearing aids are electronic devices powered by batteries that have the function of picking up sounds via a microphone and amplifying them. This amplified sound is then transmitted down the ear canal and to the inner ear. In people without hearing loss, sound normally reaches the inner ear without amplification by a hearing aid.

In cases of hearing loss, though, the sound impulses that are transmitted to the brain can often be distorted and weak; a hearing aid serves to correct these problems. Hearing aids will not perfectly restore normal hearing; indeed, a hearing aid will generally improve your hearing by one-half the loss. You will, however, find that your ability to understand and communicate with others, and to enjoy things such as TV and music, will be greatly improved.

The main function of hearing aids, then, is to amplify sounds. But if you ask the question, “How do hearing aids work?” just answering “by amplifying sounds” is too simplistic because they can do so much more. For example, hearing aids can be adjusted so that they amplify some frequencies more than others, to deal with individual types of hearing loss; indeed, modern aids have at least 5 or 6 tone controls that your doctor can use to customize your amplification system.

Modern hearing aids can also help people with hearing loss distinguish between a range of sounds, from the very soft to the very loud. They can do this by increasing the volume for soft sounds and decreasing it for loud sounds. Obviously, manually changing the volume control can be frustrating and time-consuming; many modern hearing aids have remedied the situation by including and internal automatic volume control. Many models come with both an automatic control and a manual one in order to be able to fine-tune the volume settings.

You can also add a directional microphone to your hearing aid; a directional microphone has the function of amplifying sounds that originate in front of you over sounds originating in other directions. The disadvantage of this is that if someone is speaking to you from behind, speech will be made less clear; also, these models are very susceptible to wind noise. There are a number of modern hearing aids that allow the user to switch between directional and normal microphone.

There are many models with something called adaptive noise suppression, which sense the nature of background noise and automatically regulates tone controls appropriately. Some models actually decrease the amplification of all frequencies when they detect the absence of speech.