Animal horns telephones and the cacophony in between: The history of the hearing aid
As long as there have been people there have been those who suffer with hearing loss. But when did technology become capable of helping with this? And how did society move from hollowed out ram’s horns, to being able to implant a device into the patient’s inner ear allowing them to hear? The journey has certainly taken its fare share of twists and turns along the way.
The first ‘official’ mention of trying to aid those who suffered from hearing loss is found in the Ebers Papyrus from Ancient Egypt, which offers a remedy for the “Ear-That-Hears-Badly”. The papyrus suggests injecting olive oil, red lead, ant eggs, bat wings and goat urine into the patient’s ear to restore hearing function. It is unclear whether this was to resolve hearing loss due to build-up of wax in the person’s ear, or whether it was aiming to treat those with a more profound hearing loss in a permanent way. Either way, injecting ant eggs and goat urine into a person’s ear is unlikely to do much good, although olive oil is still used today to clear hard wax build up. What we do know for sure however was that their attitude to the deaf and disabled was at the very least one of tolerance and sympathy, even if their ‘medical’ remedies couldn’t help them.
Attitudes in Ancient Greece however were less kind; people like Aristotle believed that intelligence and reason were directly linked to one’s ability to speak. Because of this, people who were deaf from birth, or who had gone deaf before they were able to speak were considered inherently unintelligent. Sadly this attitude prevailed throughout much of history. Despite this even in the ancient world of prejudice there were some that were willing to try and help those who couldn’t hear. Plato gives us the first written instance referring to people communicating through signs rather than speech, acknowledging that it can be just as effective a means of communication as vocalised language. There was no unified notion of sign language however until the 13th Century C.E. where it was found that a group of monks had developed a form of sign language so that they could uphold a strict vow of silence.
Whilst man may well have been using hollowed out ram or cow horns to amplify hearing for centuries, the first instance of a device specifically manufactured with the sole purpose of amplifying hearing was in 1588. The text describes ear horns which were shaped like the ears of animals that were known to have superior hearing. In 1610, a pupil of Galileo’s named Paolo Aproino manufactured the first ear trumpet, simply a long tubular shaped piece of metal, wider at one end than the other, which funnelled sound into the ear; the compressed sound gave the illusion that it was amplified. Despite having been invented at the start of the century however, they didn’t come into popular use until the end of the 17th century.
Frederick C Rein is credited with establishing the earliest manufacturing firm to primarily make hearing aids. He was producing ear trumpets as early as 1796 which, at their simplest, were designed much in the same way as Aproino’s, and consisted of a tapered tube that compressed sounds and funnelled them into a person’s ear. It didn’t take designers long to realise that if they flared the end of the tube or added a resonant bowl they could increase the amplification even further.
The problem was, these ear trumpets were very long and took up a lot of space. Soon people started tampering with the design in an attempt to make it more portable. The trumpets were twisted and shortened so that they resembled the shape of a bugle or were compressible much like a telescope. This way they were small enough to fit into a purse or a pocket. One particularly clever way of concealing an ear trumpet was to have it built into the end of a walking stick, so that when the hand covered the top it looked just like any other cane.
Technology continued to develop and soon people were wearing auricles rather than carting around large cumbersome ear trumpets. They were the first ‘hands free’ ear trumpets. The small trumpets would be inserted into the ear and held in place with a headband or a small wire that curled around the ear.
Development remained fairly stationary until the 19th and 20th century with the invention of the telephone. People quickly discovered that they could hear conversations more clearly through the telephone receiver than in person. Thomas Edison seized upon this and started to manufacture a new type of electrical hearing aide. As someone who had experienced hearing loss first hand he was personally invested in this new technology. In 1898 carbon hearing aids were born. The carbon microphone was originally invented for the telephone but knowing it could modulate current, Edison adapted it. By tinkering with the design it permitted the control of larger currents and produced a perceived amplification of the sound received in the earphone.
However as they were extremely large and clunky, and not entirely wearable, it took a long time for them to become popular and as such devices such as auricles remained in common use until after the second world war. Despite battery miniaturisation in the 20th century making them smaller and even wearable, the carbon hearing aide only helped people with mild to moderate hearing loss and produced a noisy scratchy sound due to the internal workings of the hearing aid.
The invention of the transistor in the 1950s led to a complete change in hearing aid technology, making them smaller, eventually so much so that they were not only wearable but that it was possible for them to be inserted into the ear canal. By the 90s digital circuitry allowed sound to be amplified, reduced, filtered and directed as needed, giving rise to a design that we are much more familiar with today.