You know that sound when someone is speaking into a microphone, and they are too close to a nearby amplifier, so you hear that awful squealing? That is called feedback and it can happen with hearing aids, too! Any time a microphone that is being used gets too close to an amplifier, it can cause this loud squealing sound known as feedback.
The official Cambridge Dictionary definition for feedback is:
The sudden, high, unpleasant noise sometimes produced by an amplifier when sound it produces is put back into it:
Jimi Hendrix loved to fling his guitar around to get weird and wonderful sounds from the feedback.
Feedback can happen with hearing aids too because hearing aids also have a microphone and an amplifier. It his helpful to have a basic understanding of the different parts of a hearing aid:
- Microphone: picks up the sound in your environment
- Processor: analyzes the sound in your environment
- Amplifier: amplifies this analyzed and processed sound
- Speaker: sends this sound to your ears
- Battery: provides power to the hearing aid so it can work for you all day long
Hearing aids can produce normal and abnormal feedback. Normal feedback is feedback that we would expect to hear from time to time, and abnormal feedback is feedback that can happen because of fit issues or other problems. So what's the difference?
You can expect "normal" hearing aid feedback when...
- You touch your ear or bring your hand close to your hearing aid. You will often hear a squeal
- When you put your hood up
- When lying down on a couch or pillow
This "normal" feedback is expected and is just part of wearing hearing aids. However, hearing aid feedback prevention and management systems in hearing aids are getting better and better. Also, if you have a mild hearing loss and wear newer hearing aids that have these features, you may not hear any "normal" feedback at all.
- Feedback when opening or closing your jaw
- Feeback with head or neck movements
- Feedback when driving in the car
These are just a few examples. This is not "normal" and means there is a fit issue that needs to be addressed.
Here are some causes for "abnormal" feedback:
- A poor physical fit of the hearing aid in your ear. If you wear instant domes, you may need adjustments or a different size or style of dome.
- A poor physical fit of a custom hearing aid or hearing aid custom tip. The venting may be too large or it may be fitting too loosely in your ear. Your audiologist may be able to make modifications in clinic or may have to send it back to the manufacturer for a remake. Your audiologist may need to take new ear-canal impressions. Sometimes, a hearing aid or hearing aid custom tip that was originally a good fit causes feedback due to weight changes. Any change in weight of 10 pounds or more can cause your ear canal to change in size and therefore your hearing aid might fit differently in your ear.
- Hearing aids not inserted properly. Your hearing aids may be a good physical fit for you and have been adjusted properly but they may be causing feedback because you don't have them in all the way. It is very important to have your hearing aids put in all the way, not only to prevent abnormal feedback but to make sure you are hearing properly and so they don't fall out.
- Wax build-up in the ear canal. Excessive wax is a very common cause of abnormal hearing aid feedback. If you have never experienced abnormal feedback issues before, and now suddenly you do, you may have a wax-build-up in your ears. Call your audiologist to schedule an appointment so they can take a look in your ears and remove any wax if needed.
If you are experiencing abnormal feedback with your hearing aids, your audiologist can help! Call us at 902-865-4455 or 902-465-4334 to book an appointment.