Why does my hearing aid whistle?

While hearing aid technology has advanced significantly, minimizing feedback remains a complex challenge. Modern hearing aids come equipped with sophisticated algorithms designed to detect and suppress feedback. Certain conditions can still trigger the whistling sound.  

Feedback is Normal Sometimes 

1.) Feedback can be normal and expected when you are inserting or removing an actively "on" hearing aid.  

2.) If your hearing aid is particularly powerful – as dispensed to those with severe or profound hearing losses. Simply switching on the hearing aid and just putting the device on a table can result in audible squealing or buzzing for others around with normal hearing. (Typically not the aid user themselves!).  The hearing aid does not have a fault for just this reason. (An explanation we have often had to give in clinic!)

3.) With rechargeable hearing aids, when they are actively charging (charger on) they are “quiet” as they have been deactivated by the charger to charge up the rechargeable hearing aid battery. When they are not charging (charger off), the hearing aids can be heard buzzing because the hearing aids are no longer charging or in stand-by mode. 

 These examples above occur quite frequently and are used as positive checks by some patients to check that their hearing aids are working and/or inserted properly.  

Feedback is not normal, but could be caused by:

The Shape of the ear:  

If the earmould or dome does not fit snugly in the ear canal, sound could escape from the speaker, loop back into the microphone and cause feedback.  The ear shape could have changed sometimes due to one losing weight, having an ear –related surgery or even due to ageing, as the outer ear cartilage collapses with extended age in some people. 

Poor placement within the ear:  

If the hearing aid dome or earmould is not worn inside the ear correctly, then poor placement can introduce gaps between the mould/dome and the ear canal, allowing sound to escape back into the hearing aid microphone. 

Poorly fitted dome or earmould:

If the earmould does not cover the contours of the ear properly, then gaps present as uncovered space can allow sound to escape leading to feedback. 

Powerful high-gain hearing aid with large venting in earmould:

If the dome or earmould is too open for the level of gain required, sound leakage can occur, leading to feedback 

Loose, broken or cracked tubing within earmould:

Gaps within the tubing or cracks in an earmould can allow sound leakage, leading to feedback. Physical damage to the hearing aid can lead to whistling sounds. Cracks in the casing, loose components, or damaged microphones and speakers can all contribute to feedback. Regular inspections and prompt repairs are crucial to maintaining the integrity of the device and preventing unwanted sounds. This is why one should service their hearing aids routinely.

Sound outlet is against the canal ear wall 

The exit opening of the sound from the mould or dome has to allow clear passage of sound into the earcanal. If placed against the ear canal wall then the sound has no means of passage but back towards the microphone leading to feedback. 

Obstructing occluding wax ,discharging fluid or water within the ear-canal. 

Ear wax can obstruct the passage of sound out of the hearing aid into the ear canal. This leads to feedback as the sound is redirected by obstructing earwax back towards the microphone. Also the earwax can embed itself into the sound exit opening of the hearing aid. This could stop output of sound from the hearing aid. Regular earwax removal is recommended for this issue. 

A discharging ear can cause feedback for the same reasons. As well as an ear which has not been dried properly following a swim, shower, or profuse perspiration in some cases. 

Inappropriate style of hearing aid for degree/severity  of hearing loss or shape of ear 

Feedback could occur if an open-fit hearing aid is fit to correct prescription levels for a severe loss. Some may try and mitigate the feedback by programming the hearing aids at sub-optimal levels.  With increasingly sophisticated feedback managers within  hearing aids, feedback could be reduced but there might be the consequence of increasing the battery drain as the hearing aid is constantly working to reduce feedback in addition to it's usual functions.  

Tips for Preventing Hearing Aid Feedback 

Preventing hearing aid feedback involves a combination of proper fit, regular maintenance, and mindful usage. Start by ensuring your hearing aid fits correctly. Visit your audiologist for regular checks, especially if you notice changes in the shape of your ear, have difficulty with insertion, difficulty keeping the hearing aid in the ear or experience discomfort. 

Regular cleaning is essential to prevent earwax buildup. Clean your hearing aids daily using a soft brush. This will ensure that sound can travel freely into the ear canal without bouncing back and causing feedback. 

If you’re experiencing persistent feedback, try lowering the volume, until you are able to see your audiologist for lasting adjustments. While it might seem counterintuitive, reducing the volume can help prevent sound from escaping and looping back into the microphone. If you need a higher volume to hear clearly, consider consulting your audiologist for further adjustments. 

When to Consult Your Audiologist about a whistling hearing aid

If you’ve tried troubleshooting and the whistling persists, it may be time to consult your audiologist. Persistent feedback can be a sign of underlying issues that require professional attention. Your audiologist can perform a thorough examination, identify the root cause, and recommend or implement appropriate solutions. 

Consult your audiologist if you notice any physical damage to your hearing aid. Cracks in the casing, loose components, or damaged earmolds can all contribute to feedback and require professional repairs. Your audiologist can help with hearing aid repairs or replacements if necessary. 

Additionally, if you experience discomfort or changes in your ear shape, visit your audiologist for a re-fitting. A properly fitted hearing aid is essential for preventing feedback and ensuring optimal performance. Your audiologist can adjust the fit or provide a new earmold to improve comfort and reduce whistling. 

Additional Tip: Is it really feedback? 

If the sound you hear is exactly like what one (check with your partner or friend) could hear when you cup your hand around your hearing aid and you are having difficulty describing the sound to your hearing professional.  You can demonstrate the sound this way to your audiologist to show the best example of what you are hearing. 

The audiologist could help you investigate.  If the sound is only heard when you are in a certain part of the house, or at specific times of the day it could be possible that the sound is coming from an external source.  

Or if the sound is heard, whether your hearing aids are in your ears or not. Then the sound is not likely to be coming from the hearing aids. 

To see a private audiologist, one who can help with these various concerns. Call us on 01634 479550 at Sonant Hearing Clinic.

Book in with us to help you deal with your hearing aid problems.

Reference 

Katz, J. (ed.) 2015. ‘Troubleshooting and Testing Hearing Aids’, in Katz, J. (ed.) Handbook of Clinical Audiology. 7th ed. Philadelphia: Wolters Kluwer Health / Lippincott Williams & Wilkins, Chapter 39, pp 749-752 

Vonlanthen, A. and Arndt, H. (2007) Hearing Instrument Technology for the Hearing Health Care Professional. Clifton Park, NY: Delmar Cengage Learning, Chapter 2, pp 21-52