1550 Theory of bone conduction through the teeth described by Girolamo Cardano.

1588 Some of the first hearing aids are described by Giovanni Battista Porta in Natural Magick. The hearing aids were made of wood and shaped like the ears of animals known to have acute hearing.

1724 Eustachian tube catheterization is discovered by a Versailles postmaster seeking to cure his own deafness.

1878 Emil Berthold first describes myringoplasty, the surgical repair of a perforated tympanic membrane. However, it isn�t until 1944 that the procedure gains considerable attention.

1898 First commercial carbon-type hearing aid produced in the U.S. by the Dictograph Company.

1912 F.H. Quix introduces the translabyrinthine labyrinthectomy during his translabyrinthine approach to the internal auditory meatus. William House reintroduces this method in the early 1960s to treat M�ni�re�s disease.

1938 Julius Lempert publishes the first successful results for his fenestration operation, used to treat otosclerosis.

1952 First transistor hearing aids developed. These hearing aids were hybrids that featured both vacuum tubes and a transistor.

1952 Samuel Rosen rediscovers stapes mobilization, used in the treatment of otosclerosis. Stapes mobilization was first used in the late nineteenth century.

1953 Zeiss Optical Company introduces the first operating microscope specifically designed for otologic surgery.

1955 John Shea reintroduces stapedectomy to treat otosclerosis.

1961 Otologist William House and neurosurgeon John Doyle, Jr. perform the first middle cranial fossa approach to the internal auditory meatus using an operating microscope. This team approach and microsurgical technique rapidly become a standard in acoustic neuroma surgery.

1984 FDA approves the first cochlear implant for marketing.

Who invented the hearing aid?
No one person invented the hearing aid. Hearing aids fashioned from horns, sea shells, or other natural material probably existed long before the ear trumpet was first manufactured. Giovanni Battista Porta was most likely the first to actually describe one of these early hearing aids. Porta wrote a book entitled Natural Magick, published in 1588, in which he describes wooden aids shaped like animal ears. How widespread these homemade aids were is difficult to say. In 1627 Francis Bacon wrote about the value of ear trumpets to the deaf as well as the use of speaking tubes. These hearing devices were probably not manufactured in the way we know it today. Most were created for specific users and reflected their tastes and needs.

Who was the first to manufacture non-electric hearing aids?
In the 1800s Frederick C. Rein of London, George P. Pilling and Sons of Philadelphia, Franck-Valery Freres of Paris, E. B. Meyrowitz of New York, and Kirchner and Wilhelm of Stuttgart were just a few of the many companies established as hearing aid manufacturers. Why did so many companies begin manufacture at this time? The answer is that technology drove the evolution of the hearing aid. The Industrial Revolution, first in Europe and later in America, created a surge in manufacturing of numerous products. Economics was also a factor; the new middle class had disposable income for products such as hearing aids, which created demand for them.

Did Thomas Edison play a role in the invention of the electric hearing aid?
Over his lifetime, Thomas Alva Edison (1847-1931) invented the phonograph, incandescent light bulbs, kinetoscopes (early movie cameras and projectors), and even stock tickers. In 1886, Edison applied for a patent on his carbon transmitter, which translates sound into electrical signals, allowing it to travel through wires and then be translated back into sound. The first electric hearing aids employed carbon transmitter technology. Although this was a great advance, Edison did not attempt to invent hearing aids themselves. Edison was also not the only inventor of the carbon transmitter. Francis Blake, Jr., of Weston, MA, gained three patents in 1881 for his carbon transmitter.

Did Alexander Graham Bell play a role in the invention of the electric hearing aid?
Alexander Graham Bell (1847-1922) was much concerned about deafness through most of his career. In 1872, Bell opened a school for teachers of the deaf in Boston and later founded the American Association to Promote the Teaching of Speech to the Deaf. Historians have noted that Bell attempted to invent an electrical hearing aid. They speculate that his wife, Mabel Hubbard, who was deaf since the age of four, was his inspiration. Although Bell's experiments did not produce the first electric hearing aid, they did lead him to his invention of the telephone. Unlike electric hearing aids, early telephones worked on magnetic principles and did not use a carbon transmitter.

Who was the first to manufacture electric hearing aids in America?
In 1899 Miller Reese Hutchison and J. Wilson established the Akouphone Company in Alabama. Miller Reese Hutchison held the patent for the first practical electric hearing aid which employed a carbon microphone or transmitter and a battery. The company manufactured the Akoulallion which sat on a table with three pairs of earphones attached. It retailed for $400. A smaller version with portable battery was sold in 1900 for $60.