Feedback is the whistling sound that the hearing aids make. The earmold may have gotten too small or the hearing aid may not be seated in the ear properly. Occasional feedback is expected when you hug your child. It is caused by “leakage” of the amplified sound. It can also be caused from too much wax in the ear canal. Objects close to the microphone of the hearing aid can also cause it. Tell the audiologist if you are having problems with feedback.