Type of Hearing Aid
A hearing aid is a mechanical device powerful enough to improve the quality of life for people with hearing loss. The levels of hearing loss range from mild and moderate to severe and profound. Those with severe or profound hearing loss benefit from hearing aids worn behind the ear, while those with mild to moderate hearing loss can wear in-the-ear hearing aids. As with other technology, the bigger the device, the more advanced the features, which cannot fit into the smaller hearing aids.
The External Shell
The hearing aid consists of the outer shell, made of plastic, and the mechanical parts that may be on the outer shell or remain inside the shell. Styles and colors of hearing aids change over time, while optional parts and accessories may provide convenience or cosmetic benefits, such as fashionable carrying cases or bands that cover the aid, but these parts do not play a role in making the unit function. There are five main parts of a hearing aid, which include the microphone, amplifier, receiver, battery, and shell. As technology advances, changes may occur to these parts, but these perpetual parts will always be the core elements of a hearing aid.
The Mechanical Parts
The three mechanical elements of every hearing aid are the microphone, amplifier, and receiver, and each of these parts may have advanced features. On the outer shell of the hearing aid is the microphone that picks up sound in the environment. The microphone sends the sound information received to the amplifier, which determines how much to increase the sounds' loudness and sends this information to the receiver, which is the piece of the hearing aid that sits in the ear canal. Sound waves then go to the brain for interpretation and processing. Basic hearing aids provide a generic microphone that picks up sound from all directions, and a basic amplifier that increases all sounds coming into the microphone. Hearing aids with advanced microphones and amplifiers provide features such as sound filtering, which eliminates or reduces the loud sounds, and custom amplification, which amplifies only specific sounds or pitches.
Custom Hearing Aid Parts
An audiologist defines the amplification needs of each patient and sends this information to the manufacturer. The manufacturer places the parts of the hearing aid inside the shell, inserting additional or custom amplification circuits, that run from the directional microphone to the amplifier. Some other features on a hearing aid include a memory button and a volume control wheel to adjust the amplification. The memory button is a toggle located on the outer shell of the hearing aid, and it memorizes user-defined program settings that were comfortable to the user in a particular listening environment.
The Power Supply
The fourth element of a hearing aid is the power supply that gives all the mechanical parts its vital life force. The power department and power requirement on a hearing aid varies. Most hearing aids have a door on the outer shell that slides open for battery changing. Some hearing aids, such as those worn in the canal, may not have a battery door because the unit is too small to fit standard-size hearing aid batteries. These units require an external charger. Some devices, such as disposable hearing aids, do not need batteries or an external unit that charges batteries because consumers must replace these units once the power runs out. Batteries can last from two days to one week, if the hearing aid requires standard-sized batteries. For disposable hearing aids, the power could last several months. The power requirements for any hearing aid depend on factors such as the type of hearing aid, how often the user wears the aid, and the proper care, maintenance and condition of the hearing aid and batteries.
References
- Cheryl Myers (self, former hearing aid wearer, now with cochlear implant)
- How Do Hearing Aids Work
