The first modern version of a hearing aid is usually considered the hearing trumpet or ear trumpet. This was an awkward, oversized devise that was shaped vaguely like a horn or saxophone. The small end was held up the ear canal while the wide opening at the other end funneled sound into the curved tube and up to the ear canal. Someone who was hard of hearing had to either hold the ear trumpet up to his ear, and the other person would have talk into it. This simply amplified the sound waves, and there was usually a fair amount of distortion.
Alexander Bell s Contributions to the Hearing Aid
When Alexander Graham Bell invented the telephone, he was actually working on ways to amplify sound of the hearing impaired. His use of a receiver and phone was translated in the early 1900 s into a form of carbon microphone. This hearing aid included a receiver in or over the ear that had multiple wires running to the amplifier, which was worn around the neck.
Although these were a great step forward, they were still cumbersome. They also used up batteries quickly. In fact, most people had to replace the batteries daily.
Fortunately, in the 1920 s, battery life was extended as newer, more efficient forms of batteries were developed. Hearing aids, however, were still fairly large. Some of them were still as big as breadboxes with wires running into the earpiece.
Throughout the 1930 s and 1940 s, new advances rapidly shrank the size of individual hearing aids. Vacuum tubes enabled hearing aids to amplify sound without needing as much equipment. Smaller batteries meant that by the close of the 1940 s, hearing aids had been developed that could fit over and behind the ear. Some were small enough that they could be creatively hidden with the right hairstyle.
The Transistor Revolutionizes Hearing Aids
In the 1950 s, the transistor enabled vast advancements in hearing aid technology. The transistor, using simple on and off switches with no moving parts, changed the entire premise of how hearing aids worked. Multiple, tiny transistors in individual units provided incremental adjustment capability. Transistors also have a high level of conductivity, making the units not only smaller but much more efficient.
Lithium batteries and integrated circuits were first put into hearing aids in the 1970 s. These smaller hearing aids soon became widely available. For the first time, hearing aids were virtually hidden in the ear, and sound quality improved dramatically.
The Next Great Leap
In the 1990 s, digital technology again revolutionized the hearing aid industry. It allowed hearing aid manufacturers to develop fully customizable hearing aids that could be adjusted to the specific hearing parameters of each person. New advances such as adaptive dynamic range optimization (sometimes called ADRO) allowed hearing aids to make continual adjustments as circumstances and the wearer s needs changed.
It s clear that the future of hearing aid technology will mean that individuals with hearing loss will have even more options in the future.
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