What Is Acoustic Feedback From Hearing Aids?

Hearing aids do a great job of amplifying sound for people with hearing impairments, allowing them to communicate with friends and family. When hearing aids whistle or squeal audibly, the effect can be disconcerting to the wearer and people around him.

Features

• When sound enters the microphone of a hearing aid, it's changed to electrical impulses and sent on to the amplifier. The amplifier intensifies the impulses, and the receiver then translates those stronger impulses into louder sounds.

Effect

• Acoustic feedback occurs when sound leaves the receiver and loops back through the microphone, where it's amplified a second time into a whistle or squeal.

Significance

• Because high-frequency sounds have a shorter wavelength than lower frequency sounds, they're more prone to escaping from the ear and re-entering the microphone. Since high-frequency losses are among the most common hearing impairments, the person wearing the hearing aid may not even realize there's feedback. Others around him, however, may notice it right away.

Tip

• If you're experiencing acoustic feedback, it's a good idea to make an appointment with an audiologist who can make sure the hearing aid fits properly, is working well, and is programmed to your common listening environments.

Warning

• If you have excess earwax, you may notice more acoustic feedback than usual.