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Find out about the latest news when it comes to topics in hearing health and hearing aids. This week, we focus on hearing aid feedback: when it happens, why it happens, and what you can do to prevent it.


Hearing aid feedback is the creation of excess noise, usually in the form of squealing or whistling, when a hearing aid is in use. Although hearing aid feedback is a common occurrence, there are a number of actions that can be taken to prevent it.

Hearing Aid Feedback


Hearing aid feedback is caused by certain mechanisms in the hearing aid system. In a hearing aid system, the sound is converted to an electric signal, and these electric signals are then converted to digital signals inside the hearing aid processor.


Depending on the settings specified by the hearing aid user, sounds can be amplified or modified accordingly. The digital signals are then converted back into their electric form and are sent to the receiver, where the signals are transformed into sound waves for the user to hear via the ear canal.


Feedback occurs when the sound that is transmitted from a microphone to its speakers is continuously received and amplified by the microphone.


The microphone will amplify a given sound multiple times if the sound is continually transmitted from the receiver to the microphone. The feedback loop that takes place is what results in the characteristic whistling or squealing that people experience during feedback.


Hearing aid feedback is most prevalent when people eat, speak, put on a hat or comb their hair. Hearing aid vents, or holes drilled into the hearing aid so that amplified noise can escape from the ear canal, are sometimes a source of hearing aid feedback.


Despite its many possible origins, hearing aid feedback usually takes place because the dome does not fit properly. It can also be due to a buildup of earwax and fluid.

Preventing Hearing Aid Feedback


The best way to fix common hearing aid problems, like hearing aid feedback, is to change the domes. Audicus hearing aid products have a disposable silicon dome. The hearing aid should fit like a cork in a wine bottle. Because hearing aid feedback can also be the result of earwax and liquid buildup, your hearing aid should be kept clean for optimal function.


Changing the ear mold is another method to counteract hearing aid feedback, and although it is relatively effective for people with severe hearing loss, the newly configured mold can often times be uncomfortable for the wearer.


Hearing aid users can be fitted for different ear molds by their clinician and can even adjust the diameter of their hearing aid vents to find vent sizes that cause the least amount of feedback.


Other innovations to help counteract hearing aid feedback are feedback cancellation systems, or FBC’s. They work by reducing the degree of amplification that is produced at the feedback frequencies. These systems have limited effectiveness and their performance varies depending on the hearing aid manufacturer.


If hearing aid feedback continues to be a problem despite having replaced the hearing aid dome, feel free to consult your audiologist!


Sources:  NIDCD, RERC

By: Aaron Rodriques