Modern Hearing Aids Are Far More Than Just Simple Amplifiers. 2019-05-20
Until just over a century or so ago, the only forms of assistance available to those with a hearing problem were simple acoustic devices, such as the ear trumpet and speaking tube. These relied on the effects of their internal geometry to amplify incoming sounds and did so evenly across the entire range of audible frequencies. Their effect, however, was of comparatively little use as a means with which to counter auditory impairment and, in fact, it was little different from that which could be achieved simply by encouraging others to shout directly into the user’s ear. Modern hearing aids owe their greatly improved performance to the development of electronic amplification techniques together with a greater understanding of auditory function and malfunction, and the real-life needs of the hearing-impaired.
The turning point came in the latter years of the 19th century with the invention of the telephone. It paved the way for successive improvements in electronic amplification - first through the use of vacuum tubes, then transistors, and eventually, solid-state circuitry, creating a rapidly-growing assisted hearing industry in the process. It was, however, the birth of audiology following the Second World War that provided the insight which led to multichannel hearing aids that are able to compensate more precisely for the patterns of impairment displayed by individual subjects. When amplifying only those frequencies at which the subject’s hearing is impaired and to a degree sufficient to allow for the extent of impairment as determined by an audiogram, the effect is to create a sound experience that is much closer to that of a hearing individual.
Digital electronics have allowed manufacturers to develop much smaller products - some may even be concealed deep within the ear canal, making them essentially invisible to others. In addition to being more discrete, the technology now enables those who wear hearing aids to interact freely with other digital devices, such as smartphones, tablets, TVs, and DAB radios, by using Bluetooth technology to establish a wireless connection to these and other compatible devices. Directional microphones provide an immersive surround-sound effect and can help wearers to identify who is speaking to them from among others who may be chatting in the same room or vehicle.
Other significant advances resulting from the use of digital technology include algorithms that can distinguish between speech and music, and adjust their processing for optimum effect, as well as the increased battery life resulting from reduced power consumption despite new functions, such as the ability to stream music. Some of the hearing aids in use today even make use of rechargeable batteries that can be quickly be replenished to provide a full 24 hours of use.