The earliest hearing aid device was developed over two hundred year ago and came in the shape of a small trumpet-like device which collected sound. Compared to the hearing aid today, the trumpet can only be described as a large and clumsy objects which provided the most basic sound amplification.
The first historical milestone came indirectly with the invention of the telephone by Alexander Graham Bell, which brought about electronic amplification via a carbon microphone, combine with battery power. It is a basic concept which has lingered to this day in area of hearing aid technology. Around the 1920’s progress had been made. Vacuum tubes which improved the level of amplification were invented and although more efficient the device was large, awkward and heavy to carry around.
However, ten years or so later in the 1930’s, important changes had taken place with the invention of miniature batteries, which made it possible for a smaller device to be made which was significantly easier to carry by the wearer. Steady progress continued to be made and in the 1950’s the transistor was invented, which had no moving parts and just a simple 'on' and 'off' switch which in effect and to a large extent, completed the early technological journey of the hearing aid.
Transistors allowed the size of hearing aid to dramatically shrink so that it could be carried about the wearer’s person. Through gradual progression, over time, it has led to the size we are all familiar with today, where it can be worn discretely behind the ears or within the ear canal. By the 1990’s digital technology was becoming more and more incorporated into hearing aid technology. This enabled improvement in sound, which served to eliminated the annoying side-effects of very loud and distorted sounds. Digital technology gave the wearer choice. The device at last could be dampened down as necessary and the frequency could be adjusted to suit the noisiest of environments.
Today history is still in the making with computer technology being linked to digital technology which ultimately will further improve the hearing aid. The hearing impaired can now have their hearing aids fine tuned to their own personal requirements, much like a visit to the optician where glasses are custom made to the individual’s own unique requirements.
The very latest development to emerge is called Adaptive Dynamic Range Optimization (ADRO). This is regarded as one of the most significant advancement in the history of the hearing aid technology to-date. The technology allows the hearing aid to self-adjust to accommodate the changing situations encountered by the wearer, moment to moment, using what is known in the industry as ‘fuzzy logic’ which is able to deliver clearer and more distinct levels of sound.
The hearing aid has come a long way from the lowly ear trumpet and with an even newer generation of hearing aids, set to incorporate the new directional microphone. The future of those with hearing impairment seems brighter, with transductors becoming ever smaller and at the same time the circuitry is reducing at a rapid rate.