Hearing loss is not merely a modern disorder, but has been an issue for humans throughout history. The history of hearing aids begins several hundred years ago, and has an interesting path, leading us to our high tech hearing aids in 2016.
The First Hearing Aids
Historical references to hearing aids go all the way back to the eighteenth century. In the 1700’s, “ear trumpets” were used to help people with hearing loss. Ear trumpets looked exactly like a trumpet, but in varying sizes. Made of materials ranging from shell, brass, copper, or the horns of animals, trumpets literally amplified sound as it travelled towards the ear. Trumpets started out large and bulky, but eventually became small enough to be hand held. They gradually improved, as people created trumpets that had “speaking tubes” which further amplified spoken sounds as they entered the ear.
The advent of the 1800’s brought the attempt to lessen the visibility of hearing aids. The trumpets and cones became smaller, and “acoustic headbands” became popular. Hearing cones and trumpets were hidden by these headbands, and also by long hairstyles and collars of clothing.
Electronic Hearing Aids
1898 brought an entirely new and exciting hearing aid. Created by Miller Reese Hutchison, the “Acouphone’ was diminutive in comparison to ear trumpets. Still bulky by modern standards, it could fit into pockets and purses. It was electric, and used a carbon transmitter. This enabled weak sounds to be amplified by an electrical current and be made louder.
Several years later, hearing aids continued to improve. In 1920, Earl Hanson created the “Vactuphone,” which utilized telephone technology. A transmitter turned sound into electrical currents and then carried and converted them so that they could be amplified in the receiver located near the ear. This was known as “vacuum tube technology,” and was widely used in electronics at the time. This improvement weighed seven pounds, which was considered to be portable at the time.
Hearing aids became wearable, albeit bulky, and were placed around the neck like necklaces. WWII technology introduced the idea of miniaturization and hearing aids in the 1950s started to shrink in size, making them easier to wear.
Bell Laboratories invented transistors in 1948, which were seen as a vast improvement over vacuum tube technology. Transistors had less distortion than vacuum tubes, required less battery power, and were even smaller. The downside to transistors in hearing aids was that they were incredibly fragile, incapable of working when coupled with any sort of moisture or body heat. Thus, the first hearing aids that used transistor technology lasted for a very brief period, meaning people either went through the expensive technology quickly or had to fall back on their vacuum tube devices.
Transistor hearing aids introduced an important concept for hearing aids. They worked by being turned on and off. This ability to turn hearing aids on and off introduced the idea of switches in hearing aids, which meant that technology could introduce different levels of on and off; this is still used with some types of hearing aids today.
Digital Hearing Aids
Digital technology started to develop in the 1960s. When it started, the idea that it could be shrunk down from huge mainframe computers to something that could fit into a human ear was farfetched. Over the years, several advances had to occur to make digital hearing aids a reality.. Computers had to get smaller. Microprocessors were invented. Silicon started to be utilized as a material for hearing aids. Something known as “multi-channel amplitude compression” was invented, which meant that sound could be separated into frequency bands. This meant that sounds that were soft or muffled could be sharpened or amplified, instead of the entire sound being amplified.
In 1975, Daniel Graupe made a major breakthrough in hearing aid technology. His “six channel hearing aid” had six different levels that the user could adjust with simply pressing a button, depending on what environment they were in at the moment. This technology can still be found on some hearing aids, and is the base for more modern hearing aids.
The 1980s and 1990s brought continued improvements, with smaller hearing aids and technologies that continued to employ dual use of analog and digital technologies. These devices were immensely popular, and brought about the creation of the pure-digital hearing aid in 1995.
Today’s Hearing Aids
Twenty years after the first all-digital hearing aids were introduced, the hearing aids of 2016 are technological marvels. From the days of huge trumpets held up to ears, and seven pound bricks that had to be carried, to today’s devices that can be the size of a fingernail, hearing aids have changed. Hearing aids today come in a range of sizes, and may fit firmly behind your ear or can be completely hidden inside your ear canal. Today’s hearing aids work like mini-computers in your ear- they can adjust to dozens of different environments on their own, without you ever pressing a button or manually adjusting them. They rely on batteries that can last for weeks, and can even sync with phones, televisions, and other technology.
The road to today’s hearing aids is a long one. Many technologies have been employed, and many improvements made, so that modern hearing aids deliver amazing sounds to their wearers.