Who Invented the Hearing Aid?

Hearing aids are small electro-acoustic devices that prove to be of great help to those with hearing loss. This device is able to amplify and modulate sounds received by its wearer. 

It consists of a receiver, an amplifier, and a microphone. The microphone receives audio signals and converts them into electrical signals. The amplifier amplifies these signals and the hearing aid wearer is able to listen to the sound received.

Preliminary forms of hearing aids have been in use since centuries. Their design has undergone significant changes over the years. Today, we find a variety of these in the market. Their designs have advanced over time.

The first hearing aids were created in the 1500s and were made of wood. Their shape and size resembled those of the human ear. By the 19th century, hearing aids were sold in many parts of the world as consumer products. However, hearing aids of those times were affordable only for the upper economic class of society.

The earliest hearing aids were bulky and trumpet-like. One end was of the shape of a funnel (a broad surface to gather sound) and had a narrow tube-like structure to carry amplified sound to the ear.

Out of the many types available today, body-worn hearing aids were the first ones to be invented. Harvey Fletcher, an American physicist working at Bell Laboratories, came up with the design of body-worn hearing aids.

The first electric device to transmit sound was the telephone, an invention of Alexander Graham Bell. Some of those with hearing problems did find it easier to listen to sounds on a telephone. With the invention of carbon transmitters for the phone, electrical signals could be amplified, further improving the hearing of sounds.

Efforts were made to adapt the telephone as a hearing aid. But this did not prove to be of much help for people with hearing problems.

Miller Reese Hutchison invented the first electrical hearing aid around 1895. Also known as the Akoulathon or microtelephone, it was like a miniature telephone with a transmitter that captured sound and transmitted it to a carbon receiver. The sound was delivered to the ear through headphones. He continued to work towards improving the device.

By 1902, it was portable and battery-operated. Miller Reese Hutchison further modified it into a device that could convert sound into vibrations, thus making it useful for those with greater hearing loss.

In 1923, Marconi in England and Western Electric in the US brought vacuum tube hearing aids in the market. They were superior in terms of the amplification and frequency response they offered. They were modified from bulky to portable. But being easily noticeable when worn, people refused to use them.

In 1938, Aurex Corporation in Chicago came up with a wearable hearing aid. In the 1940s, printed circuit boards and button batteries were introduced in the hearing aid design. Vacuum tube-based models were soon replaced by transistor-based ones.

In the 1950s, Otarion Electonics in Chicago introduced the first hearing aid in the form of a pair of eyeglasses wearable at the ear. The 'hearing glasses' design soon became popular.

In the 1960s, Zenith Radio brought hearing aids with integrated circuit amplifiers and button batteries. The device could be worn behind the ear. In the 1980s, digital signal processing chips were used in hearing aids. In the next few years, fully digital and programmable models entered the markets.

The hearing aid technology has evolved to a great extent today. Devices using wireless technologies and those with directional microphones and precision amplifiers are available. They are indeed a great relief to the old and to the hearing-impaired.