Hearing Aids’ Evolution
1. Acoustic Period
At that time, you simply used the cupped hand behind the ear technique, as well as animal horns.
2. Mechanical Period
A German researcher, Athanasius Kircher, invented the first acoustic tube in 1650. He also invented a twisted tube reminiscent of the shape of the inner ear. In the 18th century, Claude-Nicolas Le Cat created an acoustic horn that could amplify sound by up to 15 decibels.
3. Electric Period
Interesting note: Due to the fact that his wife and daughter were deaf, Alexander Graham Bell attempted to develop hearing aids by transforming sound waves into electrical impulses. That's how he invented the telephone. In 1905, a portable electric hearing aid was developed, consisting of a microphone worn on the neck, a battery and an amplifier. A year later, you would use a small box, about the size of a suitcase, called a vactuphone, equipped with a microphone connected to the ear by a cable. In 1925, the vactuphone was already miniaturized. It could now be carried in your pocket. In 1937, the sonotone developed, which was smaller and more effective.
4. Electronic Period
In 1947, thanks to the appearance of the transistor, electronics are introduced in hearing aids. In 1953, the sonotone uses the transistor in addition to a vacuum tube, thus offering reduced size and better sound quality. In 1956, the transistor allows for significant hearing aid miniaturization. The behind-the-ear analogue hearing aid begins to be used. Shortly after, hearing aids are incorporated to eyeglass frames. Around the year 1975, we see the appearance of in-ear hearing aids. Digital programming appears around the year 1987. On the other hand, amplification remains analog. The first completely digital cameras appeared on the market in around 1996. This is what allows obtaining more effective and more stylized hearing aids today.