The evolution of hearing aids

Hearing – it’s probably something you take for granted until you start to lose it. Your ears and brain do an incredible job at translating the sound waves around you into something that makes sense.

Fortunately, hearing aids help those who are hard of hearing. But, how did we arrive at the modern hearing aid? Let’s take a look.

Early hearing aids

You would have used an "ear trumpet" if you were hard of hearing during the 13th century. These were made from hollowed out animal horns, seashells or glass, and helped amplify sound.

Possibly one of the first written mentions of a hearing aid can be found in a book published in 1627 by Francis Bacon called Sylva Sylvarum: A Natural History.

He wrote, “Let it be tried, for the help of hearing, (and I conceive it likely to succeed) to make an instrument like a tunnel; the narrow part whereof may be the bigness of the hole of the ear; and the broader end much larger, like a bell at the skirts; and the length half a foot or more. And let the narrow end of it be set close to the ear: and mark whether any sound, abroad in the open air, will not be heard distinctly from further distance than without that instrument. And I have heard there is in Spain an instrument in use to be set to the ear, that helpeth somewhat those that are thick of hearing.” 

Italian nobleman Pietro Amiani provided the first known detailed description of a hearing aid that was specifically designed for people suffering from hearing loss in around 1640. He described a “desirable ear trumpet that had a sophisticated parabolic design” in his book Geometria.

By the 17th and 18th century, more powerful ear trumpets were developed. Ludwig van Beethoven is said to have used an ear trumpet when he began to lose his hearing.

Beethoven, deaf, sonata, moonlight, music, piana,

But, as the years went on, people no longer wanted big cumbersome ear trumpets – they wanted to hide their hearing devices. By the 1800s hearing-aid designs were incorporated into hats, headbands, clothing, hairstyles and even beards.

Hearing aids, electricity and telephones

The invention of electricity and the telephone, which was the first device that could transmit speech, helped advance the designs of hearing aids in the 1900s, providing the foundation for the electronic hearing aid.

A microphone, made from carbon, amplified sound using a weak signal – electricity helped make the signal (and sound) much stronger.

The vacuum tube was the next step in hearing-aid technology, which used the three-element tube invented by Lee De Forest in 1907. In 1920, Western Electric Co., based in New York City, used this technology to manufacture hearing an aid that provided 70dB of amplification.

Unfortunately these devices were not exactly portable or lightweight – they weighed 100kg and were the size of a filing cabinet. By 1924 Western Electric developed a new model where all the electronics could fit into a small wooden box, and although it was much lighter, it was still quite heavy at 4kg.

Transistor hearing aids were the next big advancement in the 1950s, as they had an on and off switch, which helped conserve battery life. They were made from silicone and transitioned from large devices worn on the body to more discreet behind-the-ear and in-the-ear-styles.

Although the analogue technology that was used had limited ability to filter speech and noise, it can still be found in hearing aids today.

The digital age

Finally, hearing-aid technology moved into the digital era in the mid-1990s and made use of digital signal processing (DSP). This meant that they were much smaller, had far better sound quality, and superior noise filtering and amplification capabilities.

Fortunately the hearing aids we have today are smaller, more lightweight and far more powerful than their predecessors. Plus, with the advancements in digital technology, modern hearing aids are able to adapt to your surroundings and lifestyle. 

Today there are two main types of hearing aids that are available, depending on your lifestyle, ear shape and needs:types, hearing aids, factoid, infographic, table

Image credit: iStock

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