What are the two most common causes of whistling and squealing of a hearing aid?

The most common causes of whistling and squealing in a hearing aid typically stem from issues related to fitting and battery performance. A loose earmold can create a gap that allows sound to escape, leading to feedback, which manifests as whistling or squealing. Additionally, a low battery can reduce the performance of the hearing aid, potentially affecting sound processing and output, which can also contribute to feedback issues.

While other factors such as worn-out batteries, dirty contacts, faulty microphones, damaged tubing, incorrect fitting, and moisture damage can impact hearing aid functionality, they are less common culprits specifically related to the feedback noises described. Ensuring that the earmold fits snugly and that the battery is charged can help mitigate whistling and squealing, addressing the root of the problem effectively.