A hearing aid is an electroacoustic device which typically fits in or behind the wearer's ear, and is designed to amplify and modulate sound for the wearer. Earlier devices, known as ear trumpets or ear horns, were passive funnel-like amplification cones designed to gather sound energy and direct it into the ear canal. Similar devices include the bone anchored hearing aid, and cochlear implant.
Read more about Hearing Aid: Types, Indications, Adjustment, Purchase Costs, Batteries
Famous quotes containing the words hearing and/or aid:
“The hearing ear is always found close to the speaking tongue; and no genius can long or often utter anything which is not invited and gladly entertained by men around him.”
—Ralph Waldo Emerson (1803–1882)
“For this invention of yours will produce forgetfulness in the minds of those who learn it, by causing them to neglect their memory, inasmuch as, from their confidence in writing, they will recollect by the external aid of foreign symbols, and not by the internal use of their own faculties. Your discovery, therefore, is a medicine not for memory, but for recollection,—for recalling to, not for keeping in mind.”
—Plato (c. 427–347 B.C.)