In the beginning, hearing aids were heavy and definitely not suitable for wearing on the body. An early hearing aid typically consisted of a separate microphone, an amplifier, headphones and a bulky battery. As the device worked best when placed on a table and used with a pair of headphones, it was troublesome to use.
Although the battery was large, it only lasted for a couple of hours at a time, upon which the battery went dead.
On top of all this, early hearing aids were expensive, and only few people could afford to buy them.
First portable hearing aids
As early as 1902, three years after the first hearing aids were available, the hearing aid became lighter. Hearing-impaired sufferers could save their energy and purchase a smaller portable device, which could be worn, and worked better than earlier models.
Although the design was smaller, the amplifier and batteries had to be hung around the neck and the microphone had to be held in the hand for the user to hear properly.
People using these hearing aids must have attracted quite a lot of attention. In addition, the size of the microphone varied in accordance with the extent of the hearing loss, so a person with profound hearing loss was compelled to use a large microphone with the hearing aid. The large table models were used by many people for many years after the first portable hearing aids were introduced.
The revolutionising transistor
Portable, unwieldy hearing aids were used, after various improvements, well into the 1950s. However, the invention of the transistor in 1947 revolutionised hearing aid technology. Until then, valves had been used in hearing aids, but the transistor made it possible to build smaller and better ones.
The amplifying ability of the transistor was superior to that of valves, and as a consequence the batteries allowed the new hearing aids to be used for longer periods of time.
The first hearing-impaired people to switch over to the new transistor-driven hearing aids had to carry them on their body, but before long, hearing aids became so small that they could be placed directly behind or above the ear. These small devices meant that people with hearing problems did not attract so much attention any more.
From the 1960s onwards, small, in-the-canal hearing aids were developed. They were not, however, as reliable as the larger, more visible behind-the-ear hearing aids, which underwent continuous improvement and became more discreet.
Common to all hearing aids was the analogue technology used for the processing of sound. The development of digital sound processing led to considerable improvements in the effectiveness of hearing aids.
Digital hearing aids are constructed with a small programmable computer and are capable of amplifying millions of different sound signals very precisely, thus improving the hearing ability of hearing-impaired people.
During the mid-1980s the first digital hearing aids were launched, but these early models were slightly unpractical. It was not until some ten years later that digital hearing aids really became successful, with small digital devices placed either inside or discreetly behind the ear.
In many cases, the new digital hearing aids improve the hearing ability of hearing-impaired people to such an extent that even people with a profound hearing loss can live an almost normal life. Today, digital hearing aids make a decisive difference to the quality of life of hearing-impaired people.