Dementia or aging?

Another thing with my own Mom's hearing aids, she refused to get her ears cleaned out correctly. Didn't like the hot water the nurse was using. Thus, the nurse had to try luke warm water which didn't work with the ear wax. Afterwards, Mom would claim she had her ears cleaned.... but the wax was still there.... [rolling eyes].

My Dad always had excellent luck with the hot water ear wax cleaning. For him it made a big difference.

Mom might not have her hearing aids inserted correctly, the ear mold, specifically. Do you hear whistling? Or maybe the inserts are clogged with wax.

My mom had to have custom molds because her ear canals were partially collapsed.

I think you must mean "conversational cues", right?

Most hearing aids making EVERTJING louder, including background noise. Many folks who use them miss subtle cues because they aren't hearing them.

Does your mom do better in one to one conversation in a quiet setting?

Your mom might be experiencing aphasia (the loss of ability to understand or express speech, caused by brain damage). My friend's mom had this. I have an aunt who has it. I found myself screaming into the phone thinking she couldn't hear me but it turned out she just couldn't process the main noun or word in my sentence -- she clearly hear everything I was saying. I'm not sure if there's a test for this, but you should have her checked by her doctor for more accurate answers.

I am so not understanding what you might consider "conventional cues".
I am 77.
At present I notice that I cannot multitask nor can I multi-HEAR. That is to say, if two things are happening at once I will automatically shut off one of them. For instance I cannot go through the grocery check-out and hear a conversation with me other than the checker; I am focused. I cannot type here on the forum and hear my partner on his own computer right next to me telling me some news (tho he says I will often respond to it).
Without HAVING an aging brain it is almost impossible to describe. I have always had a bit of an anxiety disorder that goes out of whack when things go out of order. A bit OCD. But NOW when anxiety hits I am all but useless in confusion and helplessness.
It is not easy at all to differentiate the brain of the aging and the brain of beginning dementia, so I would leave it to the experts with a neuro exam. They have those little trick questions. You know? Draw me a clock. I will tell you three words and in 15 minutes, after we chat, I will ask to you tell me those three words again. Who were our last three Presidents. And so on.
If this is a "need to know" time, then see the knowledge.
I will also say that my partner has hearing aids, and completely able to adjust them with his cell phone app and etc. But finds them worthless in some situations, annoying in others and just great in still a third subset. So ASK your Mom. Are the aids helping you. Are they annoying in some situations, etc.

MBFoster, I found this article under "CARE TOPICS" which is at the top of the page on the blue/green line. Hope this helps.

https://www.agingcare.com/articles/alzheimers-disease-dementia-warning-signs-144253.htm