Overview

Artificial aids to hearing may have been developed in ancient times to help hunters, warriors, and sailors send messages over long distances.

Eventually, similar devises were adapted to help individuals who had suffered hearing loss. Deafness can be caused by accidents, disease, or aging and the loss of sensitivity to sound can vary from partial to severe. A hearing aid can be thought of as a miniature amplifier, that is, a device that increases the level of sound for the user. The history of aids to hearing includes various kinds of ear trumpets, tubes, bone-conduction devices, and electric aids. Modern hearing aids use electric amplifiers to boost the original sound.

Background

The technology of modern medicine, including diagnostic devices and prosthetic devices, reflects the profound changes that have occurred in nineteenth- and twentieth-century medicine. By 1900, diagnostic instruments...