Small, behind-the-ear, hearing aid devices, and cochlear implants are just a couple of hearing aids that are made today. But have you ever wondered what types of hearing aids were readily available, before devices powered by electricity were created?
Throughout history, hearing aids were separated into two categories: mechanical and electronic. Mechanical hearing aids did not use outside power sources, but ordinary items were used to help people hear. Some of these items were animal horns that had been hollowed out, or a broken seashell that would have been placed by the ear to amplify surrounding noises. It could have been a big fig leaf rolled up like a tube, or the span of a cane that intensified sounds into the ear.
The Akoulallion (derived from the Greek terms “to hear” and “to speak”) was introduced in the 20th century. It was an electronic hearing aid that were also portable, and powered by batteries. This device operated with a carbon microphone and could be connected to three pairs of earphones at the same time. From that point on, hearing aids have utilized microprocessors, integrated circuits, transistors, vacuum tubes, and an assortment of digital technology to support the surrounding acoustics in order to comprehend speech.
The Very First Hearing Aids
The first hearing aids that we are aware of was not electronic or mechanical, but made with the human hands. Our ears are formed in a way that helps us acquire surround sounds. In some instances, our ears need a little help from a cupped hand in order to amplify sounds.
Hadrian, a Roman Emperor, cupped his hand while listening. Sir Joshua Reynold, an English portrait painter from the 18th-century, painted a self-portrait of himself with a cupped hand. He had allegedly become partially deaf after having a severe cold. The inventor Thomas Edison, along with sociologist and writer Harriet Martineau, also resorted to using a cupped hand to improve their hearing.
You may use a cupped hand as a visual indication that someone needs to speak louder, but are there really advantages to using a cupped hand? In two studies, human hands were used, while in three studies mannequins with synthetic hands were used. They showed the same pattern, but not the same degree. There are two areas that have powerful acoustic gain: 1-3 kHz and 5-8 kHz. The gain in these areas echo reverberations of a hollow sound that is shaped by the “pinna plus cupped-hand”. The degree of acoustic gain, in today’s terms, would be analogous to listeners who have hearing loss ranging from slight to mild.
There are two advantages to comprehending speech with your hand curved behind your ear: It efficiently increases the amount of collection surface for the ear and weakens sound from the rear of the listener. The measure of improvement in signal to noise ratio (SNR) is relevant because it can guide researchers in understanding words, depending on certain speech materials (i.e. unusual words compared to simple foreseeable sentences).
A cupped hand can support acoustic gain and enhance speech comprehension in real environments, for instance, when noise and speech are spatially separated. Speech comprehension doesn’t have added benefits that are improved from a speaker who increases their volume when reacting to the cupped hand.
Do you frequently cup your hands behind your ears? Maybe it’s time for a hearing test. Contact us at Pure Sound Hearing Aids, for a free hearing test and consultation. We offer affordable hearing aids for people of all ages!
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