The technical term for the whistling that can sometimes occur with even the best hearing aids is “acoustic feedback” or just “feedback,” and while it can be an annoyance, it does not mean your hearing aids are malfunctioning. Technological advances in hearing aids have made feedback whistling much less frequent than in past devices, but we have yet to see a hearing aid that will never whistle under certain circumstances.
Why does feedback occur?
Acoustic feedback occurs when amplified sound exiting the hearing aid from the speaker (receiver) gets picked up again by the device’s microphone in what becomes an acoustic loop. It sounds like a squeal or whistle, and it can be embarrassing and annoying for wearers as well as those around them.
Almost all hearing aids will create feedback when something is placed next to the microphone. For example, when wearers cup their hands over their hearing aids while they are in the ears, they will usually whistle. Properly fitted hearing aids should not whistle during ordinary wear when there is nothing near the microphone.
Causes of feedback whistling include:
- hearing aids that are not seated properly in the ear.
- loose-fitting hearing aids.
- blockage in the ear canal such as earwax.
- excessive jaw movement with chewing, smiling
Any time there are gaps between the hearing aid case and your ear, sound from the end of the hearing aid can leak out of the ear canal and find its way back into the microphone.
Today, most hearing aids have features built into their circuitry that reduce feedback. These systems quickly detect the feedback and eliminate it before it becomes audible to you or others nearby. Most hearing aid manufacturers include basic feedback reduction into even their basic hearing aids, but more sophisticated, high-end products may have more advanced feedback reduction systems.
If you are new to hearing aids and feedback is a concern for you, be sure to ask your Hearing Care Professional about hearing aids that most effectively control it. And, if you already wear hearing aids and have trouble with whistling, visit your Hearing Care Professional. They can determine the cause of the feedback and make adjustments to correct it.