Writing this for a friend who needs to advise his parents, but it’s good general knowledge for all. Strap yourselves in, it’s going to be a long one…
Hearing aids (private ones) come in roughly four levels. Each level up builds on the one below.
At this level, the hearing aids bring in your hearing test results, and apply a “prescription” to them. This means they calculate the amount of volume you need at each frequency (pitch) and at each input level (the volume of sound in the outside world, low, moderate, loud). Really cheap aids split your hearing test into only a few sections (called channels), so if you have a steeply sloping loss, it will not be very accurate, you’ll be over or under amplified in many areas and the sound quality will suffer.
They do help you hear better than with nothing, and they are better than an amplifier which simply makes everything louder. They will likely have a couple of very basic features such as loud impulse noise softening and frequency compression - depending on the model - but in a noisy environment they will make everything louder indiscriminately.
This tech has more channels than the one before it. It matches to your hearing test more specifically, and as a result the sound quality improves, making it easier to separate out human voices and understand speech. They may be able to adapt, via use of a button, to a couple of different sound situations. You may be able to turn off the backwards facing microphones for a crude type of noise reduction. Still, they will not be particularly helpful for speech in noisy situations and will continue to make all sounds equally loud.
This is where there is a sea change in the technology. More channels again, for more precise sound quality. Several very important features come into play. The hearing aids can (depending on manufacturer) talk to each other and compare input. They can adapt automatically to sound situations and make them more comfortable. Perhaps most importantly, they can specifically recognise and enhance speech signals, and lift them up compared to the background noise. Background noise has a specific signature (usually lower in pitch, usually steady state), whereas the nearby speech signals are different enough to be picked up by the aids and specifically amplified. As you can imagine, in a cafe or supermarket this would be incredibly useful, and that’s why it’s so expensive! If you ever leave your home or have larger family groups over, you will benefit from this technology immensely. You will also find sound more comfortable, and require less concentration to keep up with conversation. At this level the aids are normally focused on speech coming from in front of you, using directional microphones to concentrate on that source.
Ultra Advanced Level
More channels again, but for many manufacturers it is more channels than are technically necessary/helpful. Any more than 15 and we are possibly just gilding a lily! Wind noise management is usually here, which is an algorithm that subtracts microphone distortion and enables you to hear speech when the wind is blowing (a very underrated feature, but you do so miss it when it’s not there!). Enhanced noise/speech separation. Enhanced comfort. And usually, a 360 degree ‘zoom’, which means the aids are constantly searching for speech and can zero in on it whether it comes from behind, side or front.
All these are rules of thumb, and some manufacturers are better at making some features than others, but they all fundamentally have that sea change between being able to hear in noise/comfort, and not being able to hear in noise.
A good audiologist will listen to you and pull from your assessment exactly what is important to you. They will match your needs to the technology and manufacturer to fix your problems as best they can.
Steer well clear of audiologists who just say “these ones are automatic” or just ask your budget and pick the highest one at that point without telling you how your life can be enhanced. We are in the business of enhancing lives and overcoming disability through technology, not selling widgets. If they can’t explain how money translates to life experiences, take that money somewhere else. And always, always get a money back guarantee.