Guide to Coping with Feedback

Monday, May 5th · Staff Writer

(Source: HealthyHearing.com) Feedback: An introduction to that annoying, head-ache inducing, screeching sound produced by your hearing aid. With tips to solve the problem

This is one reason so many people are reluctant to go for a hearing test, accept the results and get fitted for a hearing aid that will deliver the sound of a butterfly's wings across the yard. (That is, if you want your device to be that sensitive).

Feedback. We all grew up on it from Jefferson Airplane to Green Day. Feedback is a musical art form when in the hands of a skilled musician, 3,000 amps of raw power and the guts to stand in front of a tower of six-foot speakers and set your guitar on fire. You just don't get that kind of sound from anywhere.

But you just might get that loud whistling feedback from your hearing aid and while it may be reminiscent of "Purple Haze," it's hurting your ears (even more than Woodstock, '69). Today's advanced digital hearing devices typically come equipped with automatic feedback suppression, so when it does occur it may be a sign there is a problem with the hearing device or the device needs a little tweaking to get rid of the shrieking.

So, hearing aid wearers and those about to join the ranks (yes, that's you Boomer Boy or Girl), here's an introduction to hearing aid feedback and what you can do about it.

Oh, and if you don't think this applies to you because your only 32 years old, how loud did you play your Nirvana CDs? Hearing loss isn't something for oldies, younger and younger people are strapping on the ear gear to get more from life on the hearing side. So read on. If you don't wear a hearing aid today...tick, tick, tick...it's only a matter of time.

Types of Feedback

You'd think that feedback is feedback but no. Is anything ever that simple? In fact, there are three types of feedback, and no, you don't need to know this for the test.

The first type of feedback is called acoustical feedback. This is caused when amplified sound produced by the hearing aid speaker is picked up again by the aid's microphone creating a sound loop that just gets louder and screechier. If you have ever been talking in a microphone and stand too close to the speaker, you have surely heard acoustical feedback. The same can happen with hearing aids. Most unpleasant and not too cool when you're trying to conduct a business meeting in a quiet room and all attendees hear is the whistling tea kettle emanating from your inner ear.

Second type of feedback: mechanical feedback. Pretty hard to live with but easy to fix. Mechanical feedback occurs when physical vibrations are created due to contact between the hearing aid speaker and the hearing aid casing. These vibrations are then transferred through the casing back to the microphone.

Finally, the third type of feedback is called electronic feedback. This feedback is caused by a malfunction in the device's complex circuitry, requiring the services of a hearing aid tech to fix.

Five Things NOT to Do When Your Hearing Aid Blasts Feedback

Don't tap the device on a table top to see if it stops the noises. These are rugged but sensitive devices and the chances of fixing a feedback problem by "knocking on wood" are about zero. In fact, you may do additional damage, so no tapping.
Unless you fix hearing aids for a living, don't open the casing to "see if you can fix it." Chances are you don't know an anode from a diode so what are the chances of finding the one piece of minute equipment causing the feedback problem.
Don't let your brother-in-law have a look at it. Just because someone is mechanically inclined doesn't mean they can diagnose and fix a feedback problem. Especially when it's your brother-in-law.
Don't run the device through the washing machine - even on gentle cycle. Sure, hearing aids today are water resistant but come on!
Finally, don't drive over the device in your car out of frustration. You just need a minor adjustment - or rather your hearing aid does.

The fact is, you can only lessen one kind of feedback at home.

Remember Types of Feedback

A reminder: acoustical, mechanical and electronic feedback - those are the three types. Now, if the problem is mechanical - the mic is transmitting vibrations through the casing of the device - you need visit your hearing health care professional

And if the problem is electronical, that means the case has to be opened and all of the digital bits checked - again, not something you should try at home even if "digital circuits" is your middle name.

So, that leaves acoustical feedback - the kind produced when the sound from the speaker is picked up by the hearing aid mic and recycled over and over, louder and louder. Now this you may be able to fix.

Fixing Acoustical Feedback

Here are some common causes of acoustical feedback and a few things to try before running off to the Ye Olde Hearing Aid Shoppe.

Check for ear wax.
So, okay, it's nobody's favorite job but earwax build-up is a common cause of acoustical feedback. When a sound wave hits a solid block of earwax, that sound wave shatters, sending sound every which-away including back out the ear to get re-amplified by the hearing aid microphone.

If ear wax is a problem, use a wax softener and flush the loose ear wax from the ear canal. If this doesn't solve the problem, do NOT start digging away with a hair pin or cotton swab. You're almost certain to do more damage and more serious damage. Instead, visit a hearing health care professional to have that nasty earwax excised. That should help with the feedback problem.
Check the fit.
A loose fitting hearing aid allows amplified sound waves to escape the ear canal around the hearing aid, reach the mic and off we go again in a feedback loop. And check this out - if you've been dieting and you've lost 10 or 20 pounds (good for you) that weight loss can affect the fitting of your hearing aid.

To test the fit of your hearing device, try these steps:
- Press the hearing aid further into your ear canal. If the feedback stops, a loose fit is most likely your problem.
- Place a small dab of Vaseline on the part of the device that fits into the ear canal. This liquid sometimes seals cracks, indicating a loose fit and the need for a refitting. Be careful not to get it inside the hearing aid.
- Try placing soft hearing aid wraps around the canal portion of the hearing aid. These are sponge-like wraps specifically made for hearing aids that adhere to the canal portion of the hearing aid, creating a tighter fit.
- Try putting a coating of clear nail polish on the part of the hearing aid that fits in the ear canal. Let it dry! This might just add enough circumference to create a tighter seal.
It is important to note these are all temporary remedies for a loose fitting hearing aid. You may need to visit your hearing health care professional to have your hearing aid re-cased or have a new ear mold made to prevent further feedback. But hey, if you just lost 20 pounds, that's a good problem to have.
Speaker Placement
With custom in-the-ear hearing aid devices the feedback problem may possibly be caused by an ill-fitting hearing device. When the hearing aid is built by the manufacturer, the hearing aid technician places the receiver (speaker) of the hearing aid so that will direct down the ear canal. If the direction of the receiver is off and pointing directly into the wall of the ear canal, it can cause the amplified sound to bounce back into the hearing aid and the whistling begins. This is more likely to occur for someone with a sharp bend in their ear canal.

To test if this is the cause, simply try pulling your ear lobe back. By pulling your ear lobe back you essentially open up your ear canal. If the feedback stops, this may be your problem.

With the advances in digital shell design by hearing aid manufacturers, this is a rare cause of feedback but should still be considered. Talk to your hearing health care professional if you suspect this as a possibility.
Hearing Aid damage
This is a common problem for in-the-ear devices that rest within the ear canal that are subjected to more cleaning due to wax. The sound tube may become damaged over time by aggressive cleaning, the mic may have gotten pushed in, or there could be a crack in the hearing aid casing. In the case of a behind-the-ear device, the tubing tends to harden over time and once more susceptible to cracking. Any of these scenarios could potentially cause the amplified sound to leak and become re-amplified, causing once again feedback.

Warning

Feedback can be caused by a number of factors - some under your control, others not so much. And visiting your hearing health care professional may not solve your problem the first go-‘round.

Typically, feedback comes from amplification in the higher frequency ranges so some persons may be more susceptible to feedback depending upon their hearing loss and the type of hearing aid they wear. Feedback issues do often require a trip back to your hearing professional's office - but it will be well worth it to determine the cause of the feedback.

Feedback Suppression

Most advanced digital hearing devices come with the automated convenience of feedback suppression. When the device detects a hint of feedback, it automatically adjusts itself to suppress the feedback.

Costing slight more than the bare-bones, entry-level hearing aids, these automated feedback suppression systems may well be worth a little extra on the front end for years of listening comfort on the back end.

That extra money will soon be forgotten. The feedback-free results will make you smile everyday for years to come.

This article reprinted with permission.

Article Source: http://www.healthyhearing.com/hearing_library/article_content.asp?article_id=812

Hearing Aid Resource for Consumers

Guide to Coping with Feedback