See some of the steps in custom fitting in-ear hearing aids.
Hearing aid design and function, bridled by individual engineers and manufacturing power-houses, have come a long way over the last 100 years. Originally wrought as grotesquely large vacuum-tube units coupled to cumbersome headphones, they have flowered into today's nearly invisible varieties, capable of processing millions of bits of information 'in-the-blink-of-an-eye'. The quality sound that they now deliver will, and happily so, bring a tear to that very same 'blinking eye.' Back then, as now, their basic task is to capture sound, amplify it, then deliver it to the wearer.
Contemporary hearing aids have many features, which only a few years back, were housed solely within the dreams by those in my field and by the hearing aid wearer: Noise suppression; directional microphones; speech focused amplification; and wearer satisfaction.
Noise suppression is a very important feature which enables the hearing to select identity and reduce the amplification of non-specific background sounds. In a streets-cape, for example, it lowers tire thrum and wind sounds and in a household unimportant noises, such as the hiss of a dishwasher are culled.
Directional microphones are just that; microphones which are able to capture sounds more so from one direction than from another, when the situation dictates. Generally an automatic feature it will, for example, focus upon those seated at the wearer of the wearer, In a busy restaurant, and less so from other directions. In quieter situations this feature shuts down to allow normal hearing from all directions.
Speech focused amplification, related to the preceding two, is a feature which 'zero's-in' on the human voice in high-noise situations. Old-style analogue hearing aids were incapable of this, which lead to a lot of dissatisfied wearers and a lot of apologies from those in our field. Even today's basic level digital hearings cannot claim to do much better in noisy areas.
At this point I'll stray from the point of this blog and relate it to 'real life'. The ubiquitous 'buy a pair of hearing aids for only $500' ad campaigns unfortunately do not serve the majority of wearers who often find themselves socializing, shopping or working in noisier places. (Land too can be purchased for cheap - in central Florida - but most people will regret that decision as well.) Like any investment, it's not how much you are saving, rather it's how much you may have wasted. I will note, however, that reduced feature hearing aids are absolutely fine if your lifestyle in almost exclusively in quiet places, but venture out for a day of shopping or socializing within larger venues or family-style restaurants and just when you need hearing aids the most, is exactly when they will let you down. At the other end of the scale, high-priced hearing aids are really only necessary for very active lifestyles in noisier places; it's the mid-range products which are suitable for most people, most of the time and in most situations.
Now back to the original point of this article- How do Hearing Aids Work? Hearing aids gather sounds from the environment, then processes them to mirror the hearing loss of the wearer; if you have fairly good low-frequency hearing, then the aid will not amplify much in this area, but would do so heartily in the high-frequencies, if that's where the majority of the loss is found. Another step in the process is to reduce the non-speech sounds, such as that tire or dishwasher and at the same time glean speech from the environment, making it understandable. The last step is to deliver it through tiny speakers, or more correctly receivers, into the ear canal.
I could blab in this blog for pages and upon pages about the finer points of how hearing aids work and how they are, at any one time, therapeutic, rehabilitative and confidence building devices, but they are, in just plain language, devices which makes life easier…..if set up correctly.
The first child in America to receive this special trial technology.