How do they do it? How is it that some contestants can see:
' __ o_ _ _un' on a game show and know that it says “home run”.
It is because they have strong visual processing ability in the visual cortex and can see what is not there.
Visual processing can be used as an effective analogy to auditory processing. With hearing loss, the ear is unable to deliver the full auditory spectrum to the brain, so the brain needs to be able to effectively fill in the blanks to understand the message. Some brains are excellent at this task. Think of the group of twenty year olds at the bar not seeming to have any problems hearing one and other.
It is because their brains are able to fill in the blanks of what the ambient noise is masking.
Auditory processing abilities are different in us all. Generally, the older we get, the more of the signal needs to reach our brains to understand the message.
Hearing aids are an important part of this equation, but they are not 100% of the solution.
Two people who have identical hearing loss could function quite differently depending on how well, or how poorly they can process auditory information.