Hearing aids can sometimes produce an irritating whistling sound, known as acoustic feedback. This occurs when amplified sound escapes the ear canal and is picked up by the hearing aid’s microphone. Understanding the causes of this whistling can help resolve the issue and ensure comfortable use.
Understanding Hearing Aid Feedback
Acoustic feedback in hearing aids functions similarly to when a microphone is placed too close to a speaker, creating a high-pitched squeal. In a hearing aid, sound travels from the device’s receiver, which acts like a tiny speaker, into the ear canal. If some of this amplified sound leaks out of the ear and is then captured by the hearing aid’s microphone, it creates a continuous loop. The microphone re-amplifies the escaped sound, sending it back to the receiver, resulting in the audible whistling sound. While modern hearing aids often include feedback cancellation features, these technologies do not always prevent all instances of whistling. Whistling usually indicates an interruption in the intended sound path or an issue with the device’s seal within the ear.
Whistling from Fit and Placement
The fit and placement of a hearing aid are frequent contributors to whistling. If the earmold or dome does not create a tight seal, amplified sound can escape and be picked up by the microphone. This loose fit can occur if the hearing aid is not inserted correctly, or if the ear canal changes shape over time. Temporary whistling can also happen when external objects come too close to the hearing aid. For instance, wearing hats, scarves, or even a hand cupped over the ear can block the sound from entering the ear canal properly, causing it to bounce back to the microphone. Jaw movements, such as chewing, talking, or yawning, can momentarily alter the shape of the ear canal and disrupt the seal, allowing sound to escape and trigger feedback.
Ear Health and Whistling
Conditions within the ear can contribute to hearing aid whistling. A common cause is excessive earwax buildup. When earwax obstructs the ear canal, it prevents the amplified sound from reaching the eardrum effectively. Instead, the sound reflects off the blockage and travels back to the hearing aid’s microphone. Beyond earwax, ear infections or swelling can also impact the hearing aid’s fit. These conditions can alter the ear canal’s shape, compromising the seal of the earmold or dome. Regular ear hygiene and professional ear care are important to prevent persistent whistling.
Hearing Aid Device Issues
Sometimes, the whistling sound originates from the hearing aid device due to wear or malfunction. The tubing that connects to the earmold in Behind-The-Ear (BTE) models can harden, shrink, or crack over time. This damage can pull the earmold out of position or create a sound leak, leading to feedback. Internal components of the hearing aid, a damaged microphone or receiver, can also contribute to whistling. While less common than fit or earwax issues, a loose internal wire or a tiny crack in the casing can disrupt the device’s sound processing and cause feedback. These problems usually require examination and repair by a hearing care professional.
Addressing Whistling Concerns
When experiencing hearing aid whistling, several steps can address the issue. First, ensure the hearing aid is inserted correctly and fits snugly in the ear, as improper placement is a common cause. Gently clean the hearing aid and check for any visible earwax or debris on the device, as well as checking for excessive earwax in the ear canal. If the hearing aid volume is set too high, slightly reducing it can often eliminate whistling. Regular maintenance, including daily cleaning with a soft cloth and checking for damage to tubing or earmolds, helps prevent feedback. If these initial self-checks do not resolve the whistling, or if there is significant earwax impaction, ear pain, or suspected device malfunction, consult a hearing care professional. An audiologist can assess the fit, address ear health, or perform repairs or adjustments.