History of the Hearing Aid

Modern hearing aids are miracles of technology. They consist of miniature amplifiers, transmitters, and computers. Through the use of modern hearing aids, many people are able to experience the world around them instead of living in silence and confusion. But hearing aids are far from new inventions. They have a long and lively history.

The First Hearing Aids

When do you think the first hearing aids were produced? Think it was about the time of the microphone or telephone? Think even further back. The first hearing aids were known as ear trumpets. These funnel-shaped devices came into existence in the 17th century. Ear trumpets gathered sound, strengthened it, and delivered it directly to the ear drum. The Jesuit priest, Jean Leurechonin, described one in his writing published in 1634.

Commercial production of the ear trumpet didn’t begin until 1800 in a factory in London. Before that time, ear trumpets were individually made for each client.

Electronic Hearing Aids

Telephone technology led to the invention of the first electronic hearing aids. With the invention of the telephone, man had learned to control the loudness and frequency of sounds as well as their transmission.

In 1898, Miller Reese Hutchinson created the Akouphone. He used a carbon transmitter and an electrical current to increase the strength of the signal. It wasn’t until 1913 that the first commercially made electronically-amplified hearing aids were produced by Siemens, a company that continues to manufacture hearing aids today.

In 1920, Naval Engineer Earl Hanson obtained the first U.S. patent on a portable hearing aid that made use of a vacuum tube. He called it the Vactuphone. He took a telephone transmitter and used it to convert sounds into electrical signals that were amplified before being sent to the receiver. At seven pounds, it was considered portable and lightweight! Western Electric began selling vacuum tube hearing aids based on his design in 1923.

Miniaturization, World War II, and the Transistor

The next 30 years would provide more innovation and advancement in hearing aid technology than the past 100 years.

First, the vacuum tube design was improved with miniaturization. By 1937, the first wearable vacuum tube hearing aids were available in the U.S.

During WWII, the need to miniaturize electronics was crucial to the war effort. Miniaturized electronics were used in weapons and factories. After the war, what had been learned was applied commercially. In 1949, Zenith introduced the Miniature 75. It only weighed six ounces, used four vacuum tubes, and was small enough to fit in a shirt pocket.

When three scientists with Bell Laboratories invented the transistor, they had no idea the impact it would make on the world. In the world of hearing aids, transistors could replace vacuum tubes. The transistors were smaller than vacuum tubes and used less battery power. However, the first transistors presented problems. They were sensitive to moisture and body heat. Coatings were developed to overcome these problems. Hearing aids that utilized transistors were state-of-the-art until they were replaced in the 1970s by the next big thing.

Microprocessors, Digital Technology, and the Hearing Aid

The next big leap forward came with the invention of the microprocessor. Scientists had studied the use of computers to improve hearing, but because of the size of computers at the time, it was not considered a practical application. When the microprocessor was created in the 1970s, miniaturization could be taken to a whole new level.

About the same time as the first microprocessors were being built, Edgar Villchur was playing around with amplitude compression. Amplitude compression is a fancy way of saying that a sound has been divided into bands, and each band can be handled separately. His technique is still used for controlling the environment in which a hearing aid is operating.

In 1982, at the City University of New York, the first hearing aid to use microcomputers to process signals in real time was developed. It used FM technology to transmit signals to be processed by the microcomputer.

In 1989, the behind-the-ear hearing aid was introduced. Finally, hearing aids were small, lightweight, and effective. The first all-digital hearing aid was developed by Oticon in 1995 and shared with audiological labs for further research. By 1996, the first all-digital hearing aids were offered for sale by Widex.

Hearing Aids Today

New technology continues to be developed. Each development may be the next amplitude compression or vacuum tube discovery. If Earl Hanson could see the current version of his invention from 1920, he would be amazed. Who knows what the next 20 or 30 years may bring?