Modern hearing aids are complex and custom-made digital electroacoustic devices that can be computer programmed to amplify sounds at certain frequencies. While the technology used in digital hearing aids has dramatically increased in the last fifty years, all hearing instruments retain the same basic functions and pieces.

Basic Hearing Aid Functions:

In all hearing aids sound waves enter through the microphone, which converts acoustic signals into electrical signals or pulses. The amplifier then increases the strength of the electrical signal and cleans up any noise it detects. This electrical signal is then converted back into an acoustic signal so that the user can hear it. The receiver then channels the sound into the ear canal. A battery supplies the needed power for these conversion processes. Many digital hearing aids also have many features and controls like toggle switch, volume control wheels, push buttons, remote controls, and directional microphones that enable the wearer to hear better in different listening environments.

Hearing Aid Styles

All of theses styles differ in size and function. Some are so small that no one can even tell you are wearing a hearing aid; some are so powerful that even the most profound hearing loss can be helped. The right hearing aid for you depends on the technology level you need, your hearing loss, your hearing needs, your lifestyle, your budget, and personal preference. Larger hearing aids typically have larger batteries which can last longer than smaller hearing aids. They can also have more features such as directional microphones and telecoils (for telephone usage) and have a lower price tag. Smaller hearing aids have less features, but they are virtually invisible.

Hearing Aids are available in around seven different styles: Body, Eyeglass, Behind The Ear (BTE), In the Ear (ITE), In the Canal (ITC), Completely In Canal (CIC), Receiver in the Canal (RIC), and Open Ear (OE). While body and eyeglass aids comprised most of the hearing aid market 50 years ago, they are only a small percentage of hearing instrument sales today. This is because the other styles of hearing aids are smaller and more advanced.

BTE (Open Ear, Receiver in Canal, and Traditional)

Behind-The-Ear (BTE) hearing aids are extremely flexible for all types of hearing loss. The hearing device is housed within a curved shell that sits behind each ear and delivers sound through a tube. A traditional BTE delivers the sound via a small tube into a custom fit earmold. A more recent innovation is called open ear technology and receiver in canal technology. In these two styles the sound is delivered via a very thin tube into an earbud which is a small, flexible, and comfortable piece. This type of system provides enhanced natural sound quality for both outside sounds and your own voice.


In-The-Ear (ITE) hearing aids are very easy to operate even if the user has poor dexterity. The hearing device is housed within a custom-made shell that fits comfortably inside each ear and delivers sound directly to the ear. This hearing aid typically fills the outer part of the ear.


In-The-Canal (ITC) hearing aids can barely be seen and are very easy to operate, even if the user has poor dexterity. The hearing device is housed within a custom-made shell that fits comfortably inside each ear canal and delivers sound directly to the ear.


CIC hearing aids are virtually invisible to others. The hearing device is housed in a tiny shell that fits comfortably and completely into each ear canal. The device is removed from the ear canal by pulling a tiny cord. Where these miniature instruments are both powerful and cosmetically appealing, some features- like volume control, are not available simply because the devices are so small. This style is available with traditional small vents, or with larger vents that provide an open ear feeling.

The hearing aid style and technology level that is right for you depends on your hearing loss, lifestyle, and budget. Talk with your audiologist or hearing care professional about what is right for you.