Hearing Aid and Hearing Aid Technology Development and Innovations since the Seventeenth Century
The earliest type of hearing aid is actually still in use today. Whenever you see someone cup their hand behind their ear, you are witnessing the first form of hearing assistance in action. The first real hearing aids, however, were the long trumpets used by sailors to hear the voices of other sailors calling to them over long distances at sea. Later in the seventeenth century, smaller versions of these ear trumpets had been adapted to help those with hearing loss; they took the same form, that of a cone-shaped device pointed at the source of the sound and inserted into the ear. Around the same time, the Metal Ear was created and sold to individuals with difficulty hearing. The Metal Ear was molded out of metal in the shape of an oversized ear and worn directly over the actual ear. Fast-forwarding to the 19th century, the next innovation was a type of acoustic horn sold under the names such as Cornets or Auricles. These devices were portable, but cumbersome. The end collecting the sounds was generally placed in a strategic orientation on a table or carried in a purse. A flexible tube then carried the sound to the ear.
The first electric hearing aids arose out of the invention of the telephone, and appeared in 1898; they basically functioned like ear trumpets, but they did succeed in widening the frequency range people could hear through them. A hearing aid using vacuum tubes was patented in 1921. The vacuum tube – based hearing aids wasn’t commercialized and sold to the public until 1934 because of its large size and bulk. It consisted of a microphone, an ear receiver, an amplifier, and two batteries, which only lasted for a single day. After that, there were no significant improvements in hearing aids until 1947, when the transistor was invented. Even then it wasn’t until 1952 that a transistor-based hearing aid became practical, because it turns out that transistors were sensitive to dampness. The next round of innovation was fueled by the integrated circuit – first developed in 1958. This technological advancement lasted in the 1970s.
The digital circuit and the microprocessors allowed hearing aids to take a big leap forward. Many new features became possible such as noise and feedback management and directional microphones. Microprocessors also enabled greater audio clarity and miniaturization. Unfortunately, these devices were expensive and had to be hand-crafted, requiring a wait of several weeks before you could obtain one. The first commercially successful digital hearing aid was created in 1987, and used a body-worn processor connected via a wire to a receiver in the ear. The first all-digital hearing aid was introduced in 1996, and advances in technology have now made them the standard, possessing features undreamed-of by the 17th-century ladies with their ear trumpets.