Everyone understands that hearing loss means that people can no longer hear the softer sounds that are important to understanding.
The thing that is not often discussed is that people with a hearing impairment also have a reduced ability to process the sounds that they do hear. 'the elephant in the room'
An example of this is that when we were younger, in a crowded room, we could have a conversation with someone across the other side of the room and understand most of what was said. As we age or develop a hearing loss, this is no longer possible. The fine tuning is gone, comprehension is lost.
So, the solution is to deliver more content and less noise. More content gives you more 'clues' for understanding, less noise reduces any 'masking' effects from competing sounds.
Hearing aids are a great solution for assisting you in one-to-one conversations in quiet, but they do not help if there is background noise or any distance greater than 1.2 metres from the sound source of interest.
Fundamentally, the issue is the small physical size of the microphone element.
The anatomical structure of the ear provides directionality and considerable mechanical amplification and tuning. By placing the microphone in a position other than directly on the eardrum (and with an active element that is a similar size to the surface area of the eardrum), an ear level device such as a hearing aid or implant cannot gain any advantage from this great natural biological design.
A better choice is an assistive device that can pick up the sound from the source (or at least, near the source) and deliver it directly to you without the limitations of a small microphone situated in an inappropriate location.
There are three factors that need to be overcome to increase your understanding: The quality of the sound you hear (no compression or other distortions) The Signal to Noise Ratio (more signal, less noise) Inverse Distance Law (Less Distance, better SNR)