Behind-The-Ear (BTE) Style Transistor  Hearing Aids—General Information

Behind the ear hearing aids (BTE) started to appear on the market around 1956. It is difficult to pinpoint which company was the first to produce a BTE, however, both Zenith and Beltone were producing large BTEs in 1956 and 1957. These early BTEs used discrete components and while most of the components needed were available in miniature by this time, the hearing aids were still relatively large in comparison to today’s BTEs.

Ear level hearing aids were a major step forward in solving many of the problems for hearing aid wearers. It was now possible to provide binaural amplification, not generally available in body style hearing aids. There were a few binaural body aids manufactured, but these were relatively large and the microphone placement was not ideal for binaural listening. Some wearers were prescribed "Y" cords which allowed a receiver to be worn in each ear, but still giving monaural amplification.

In designing the BTEs to satisfy severe hearing losses, there were problems to overcome. One of these was the possibility for feedback by having the microphone and receiver enclosed within the same case. The earliest BTEs solved this problem by using an external receiver, and in fact used the same button receiver used on body aids up to that time. The problems were quickly resolved with better microphone and receiver designs and today BTE hearing aids are available for severe to profound hearing losses.

The integrated circuit, which allowed many transistors and other components to placed on a single chip was invented in 1959 and the first patent issued in 1961. According to Berger¹ the first hearing aid to use an integrated circuit was the Zenith Arcadia in 1964.

Today all hearing aids use microchips and microprocessors in their design and this has led to much smaller and more discrete styles of BTE hearing aids today. For more information on the integrated circuit visit the website Inventors of the Modern Computer.

Digitally-Programmable Analog Hearing Aids

Digitally programmable analog hearing aids use analog signal processing, however, the processing is controlled by digital parameters that can be adjusted by an audiologist. In addition, some analog aids have several "programs," or sets of parameters, for different listening environments.

Hybrid technology was first patented in 1977. The first digitally-programmable Widex Quattro was introduced in 1988.

Digital Hearing Aids

The first digital hearing aid to appear on the market was the Nicolet Phoenix. It was developed in a joint venture between the University of Wisconsin and the Nicolet Instrument Corporation in 1987.

This device was a two part system consisting of a body worn processor and a behind the ear hearing aid connected together with a wire. Very few of these devices were ever made.

In 1989, they were able to manufacture a one-piece behind the ear hearing aid containing both the processor and hearing aid. It was powered by three 675 batteries.

It is believed that only one of the behind the ear aids was used by a Wisconsin resident for over three years without problems. It was apparently never put into full production.

Unfortunately, the Hearing Aid Museum does not include a sample of the Nicolet Phoenix hearing aid. However, you can view one online in the Kenneth W. Berger Hearing Aid Museum and Archives at Kent State University.

The first commercially-successful digital hearing aid was the Widex Senso which came out in 1996. Oticon had developed a digital hearing aid in 1995, but instead of putting it on the market, they sent it to audiological research centers around the world for further research, thus inadvertently giving Widex time to "one-up" them. However, when Widex released their Senso, Oticon immediately put their DigiFocus digital hearing aid on the market as well, also in 1996.

Today all major hearing aid manufacturers produce digital hearing aids. They come in many models and in all styles including Behind the Ear, In the Ear and In the Canal aids.

Digital hearing aids offer many advantages over the older analog aids. These advantages include such features as digital noise reduction, digital feedback cancellation, and directional microphones combined with multi-channel digital signal processing.

The majority of hearing aids sold today are of the digital variety and may soon completely replace analog aids.

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¹The Hearing Aid, It’s Operation and Development by Kenneth W. Berger (1970)