I think sometimes, understandably given the emotional component, we put more weight on the word “dementia” than it really deserves? It’s just a reduction in cognition beyond what we would expect as measured by some specific tests. It may well be that the hearing loss was resulting in increased listening difficulty which drew upon cognitive reserves and reduced cognitive bandwidth for other functions, and once the hearing improves and the cognitive load is reduced, thinking improves. So, on one hand you think, “well then that wasn’t really dementia”, but in so far as dementia is just reduced cognition measured on some particular tests, it was. Maybe with time and better understanding, we actually will cut this out of our understanding of what dementia “is”, and maybe there will be other factors that further improve it, finally narrowing down what we call “dementia” to a very specific disease process. So, there’s a bit of semantic witchcraft there.
In terms of permanent damage of untreated hearing loss: We know that in cats when you induce a reversible hearing loss the auditory cortex re-organizes and will also start to be taken over by other brain systems (vision). When you reverse the hearing loss, depending on the length of auditory deprivation, SOME of the original organization returns but not all of it. From an anecdotal clinical perspective, it also appears to be the case that long-term auditory deprivation can result in a loss of speech clarity (as judged by max word recognition scores) that does not fully return after consistent amplification. So there is some reason for concern, and really it is consistent with a lot of other parts of our body that will suffer when left to disuse and return to a variable degree depending on age, etc. (Edit addition: We can probably also draw insight from cochlear implant outcomes after auditory deprivation, which are clearly better the shorter the deprivation. Yet criteria for implantation are still looking at years-long time frames.)
But what we DO NOT KNOW at this point is what length of what type of deprivation we should be concerned about. At the base, you and I agree. It’s one thing to talk about this stuff and quite another to use it as a high-pressure sales tactic.
-ish? I’m actually a music-all-the-time person. I just don’t like parties with too many people because I’m an introvert and find that level of socialization exhausting. But despite a very mild hearing loss, my auditory processing is good and background noise doesn’t bother me from a comprehension perspective the way it does some of my really normal-hearing friends.