Hearing Aid Basics
WHAT IS A HEARING AID?
A hearing aid is a small externally-worn device used to collect sounds with microphones and make those sounds louder through a small speaker in the ear canal. One way to think of it is that is like a tiny megaphone for your ear! Typically, they are best suited for people with mild, moderate or severe sensorineural hearing loss, but they are often used outside of those parameters. Some people do better with hearing aids than others.
A hearing aid is generally worn in or behind the ear. A hearing aid is comprised of three basic parts: microphone(s), an amplifier, and speaker(s). The hearing aid receives sound through the microphone which is then converted to electrical signals and transmitted to the amplifier. The amplifier boosts the power of the signals, attempts to compensate for your hearing loss, and then transfers the signal to the ear through the speaker. Nothing is implanted, and everything is external. No part of the hearing aid integrates directly with or is connected to body.
There are many different types of hearing aids available on the market. Hearing aids vary widely by costs with some being available for a few hundred dollars while others are several thousand. The main differences between hearing aids are found in:
Design (e.g., size and color)
Technology (e.g., analog vs. digital)
Special features (e.g., wireless connectivity, activity sensors)
The selection of hearing aids is based on the type and severity of hearing loss, listening needs, lifestyle, and pocketbook. In many instances, the hearing aid selection at your local retail hearing shop is limited by the business relationship(s) your audiologist has with certain hearing aid manufacturers (do you research online first to understand what is really available).
HEARING AID DESIGNS
Hearing aids vary in size and the way they're placed in your ear. For instance, some aids have earmolds or earpieces connected to the device to direct the flow of sound into the ear. Other devices are contained completely within the ear canal. Below is a list of some of the most common hearing aid styles, beginning with the smallest, least visible in the ear.
Completely in the canal (CIC) or mini CIC
Molded to fit inside the ear canal
Improves mild to moderate hearing loss in adults
In the canal (ITC)
Molded and fits partly in the ear canal
Improves mild to moderate hearing loss in adults
In the ear (ITE)
Made in two styles — one that fills most of the bowl-shaped area of the outer ear and one that fills only the lower part
Improves mild to severe hearing loss
Behind the ear (BTE)
Hooks over the top of the ear and rests behind the ear. A tube connects the hearing aid to a custom earmold that fits in the ear canal.
Appropriate for people of all ages with almost any type of hearing loss
Receiver in canal or receiver in the ear (RIC / RITE)
Similar to a BTE hearing aid with the speaker or receiver in the canal or in the ear. A tiny wire, rather than tubing, connects the pieces.
Open fit
Is a variation of the behind-the-ear hearing aid with a thinner tube
Keeps the ear canal open, allowing for low-frequency sounds to enter the ear naturally and for high-frequency sounds to be amplified through the aid
A good choice for people with mild to moderate hearing loss
HEARING AID PROCESSING STRATEGY
Hearing aids work differently depending on the technology used. There are many small differences, but a big difference is between analog and digital signal processing. Choice between the two is all about preference and type and level of hearing loss. Nearly all hearing aids nowadays are digital and analog hearing aids are few and far between. Nevertheless, it’s important to discuss the differences between the two.
Analog processing allows for more incoming sound information to be used (i.e., it is not broken up by digital processing), but less can be done to manipulate the signal. Essentially, analog devices amplify the entire input signal with some minor programming. Audiophiles and people who enjoy the entire range of sounds might prefer analog signals. People with a “flat” or easily programmed hearing loss are better suited for analog devices.
Digital processing allows for an audiologist to make more adjustments for hard to program hearing loss, and is better suited for people who don’t do well when all sounds are amplified. Digital processing “chops” or “cuts” the input into digital signals which can produce an exact duplication of sound but are not longer than the full sound input. In other words, digital aids can analyze speech and other environmental sounds which allows for more complex processing of sound in the amplification process. In this way, the aids are essentially improving their own performance in specific situations. They can be programmed to better fit the needs and patterns of a certain type of hearing loss.
HEARING AID SPECIAL FEATURES
Many hearing aids are equipped with additional special features that can assist in improving your ability to hear in certain situations. Some of these features are as follows:
Direct audio input
Directional microphones
Environmental noise control / noise reduction
Feedback suppression
Rechargeable batteries
Remote controls
Synchronization
Telecoils
Variable programming
Wireless connectivity
It’s important to note that hearing aids may not be the best solution to your hearing loss, so it’s advised to explore all options. As mentioned previously, do your research online as many retail hearing loss centers are closely tied to certain manufacturers. You may think they have all options, but there are strong incentives to sell more of one brand over another. Buyer beware!
Resources:
National Institute on Deafness and Other Communicative Disorders
Sponsored by Envoy Medical