A high-pitched whistle or squeal that’s made when an amplified sound is picked up by a microphone and re-amplified. For example, it occurs when the sound coming out of a hearing aid leaks out of the ear canal, gets back into the hearing aid’s microphone and is amplified over and over until all it does is howl at its maximum loudness. Feedback can be caused by as earmold or hearing aid that does not fit properly, from a cracked or damaged earmold (or tube in BTE hearing aids) or from a damaged hearing aid. Many modern digital hearing aids have special anti-feedback circuitry to prevent (or greatly reduce) feedback.
Home Glossary Terms Feedback