A sudden, high-pitched whistle or squeal from a hearing device is known as feedback, a common acoustic phenomenon that can be startling and disruptive. This sound occurs when amplified sound leaks out of the ear canal and is re-captured by the hearing aid’s microphone, creating a continuous, looping signal. Feedback signals that the acoustic seal between the device and the ear is compromised. While modern digital hearing aids have sophisticated suppression systems, the issue often points to a simple physical cause that the user can resolve.
Addressing Immediate Fit and Volume Adjustments
The most frequent cause of feedback relates to how the device is currently seated. Ensuring a proper, deep insertion to create a secure acoustic seal is often the quickest fix. Gently push the device further into the ear canal until the dome or earmold feels snug and the whistling stops, preventing amplified sound from escaping back toward the microphone.
Checking the volume setting is important, as excessive amplification is a common trigger for sound leakage. If the volume is set too high, the sound pressure may force the amplified sound out of the ear, initiating the feedback loop. Slightly reducing the volume can immediately stop the squeal while still providing adequate amplification.
External objects positioned near the device’s microphone can also reflect sound back, causing feedback. Proximity to surfaces, such as when holding a telephone, wearing a hat, or leaning against a high-backed chair, can cause sound to bounce directly into the microphone. Users should also be mindful of hands, scarves, or clothing items brushing against the ear or device. BTE devices are generally less prone to proximity feedback than smaller ITE models due to the greater separation between the microphone and receiver.
Essential Maintenance and Hygiene Checks
When immediate fit adjustments do not resolve the whistling, the next step involves checking the physical condition of the ear and the device components. Earwax buildup is one of the most common causes of feedback, acting as a physical obstruction that blocks the sound pathway. When sound hits this wax plug, it reflects back out of the ear canal and into the hearing aid microphone, even if the device is perfectly fitted.
Users should regularly inspect the ear canal for visible wax and use the small brush or wax pick provided by the manufacturer to clean the sound bore or receiver opening. For devices with domes, the soft tips should be removed and cleaned or replaced every few weeks, as excessive wax buildup compromises the seal.
The physical components of the device, such as the dome, earmold, and tubing, are subject to wear and tear that can lead to feedback. Tubing used in BTE models can become hard, cracked, or shrunken over time, which breaks the acoustic seal and necessitates replacement. A cracked earmold or a shrunken dome will also fail to create the necessary tight seal.
Moisture from humidity or perspiration can damage the internal microphone or receiver. This damage can lead to electronic feedback or a muffled sound. Using a drying kit is necessary to manage moisture issues.
When to Consult a Hearing Professional
If the feedback persists despite careful attention to fit, volume, and maintenance, the problem likely requires professional intervention. An audiologist can perform an acoustic reprogramming of the device, which involves adjusting the frequency response or gain settings. This is often necessary if the shape of the ear canal has changed due to weight fluctuations or natural aging, altering the acoustic properties of the ear.
The professional can also update the hearing aid’s digital feedback suppression system, a specialized program designed to cancel out the whistling sound without affecting external sounds. If the audiologist determines that the whistling is purely mechanical, they may need to take a new impression of the ear. A new earmold or custom-fit dome ensures a perfectly snug fit, which is the most effective way to eliminate sound leakage permanently.
Persistent, sudden feedback that occurs without any apparent cause may signal a physical malfunction within the hearing aid itself. A hairline crack in the shell, a loose microphone, or a failing receiver are internal issues that compromise the seal or the electronic circuitry. These problems necessitate a physical repair, which an audiologist or technician can diagnose and arrange with the manufacturer.