Yesterday and several days lately--I have been really hit with 'brain fog'! The feeling that my head is under such pressure, and makes having conversations, going anywhere, making decisions, talking on the phone--etc. very uncomfortable. The head pressure--no pain--and the feeling one might 'pass out' is scary at times. I have chronic a-fib too--meaning it's with me most of the time, so never know if it's the Meniere's or the a-fib or both. I read where some studies show 'brain fog' is not a symptom with Meniere's. But here, I've learned that many have it! Makes one miserable and finally you just 'break down and cry'. And after a good nights rest, 'sometimes' it is better the next day but not lately. Seems to be daily in varying degrees. I know JOH recommends Vincopecitine (not spelled correctly). But with my a-fib and other b/p meds, etc. the OTC meds are not recommended for me. Sure hope this eases as now instead of having difficulty portions of the day I seem to be dealing with this most of the day!
I'm probably not much help as I am very new to all of this but I do empathize with you. My brain fog comes and goes but is very bothersome when I do have it. Mine seems to come in batches. My memory is horrible. I know what you mean about breaking down and crying. I've done that a couple of times lately because of the brain fog and because of how Meniere's has changed my life in the past few months. I feel for you. You are definitely not alone.
The part cognition plays with Menieres is something many of us experience. It's horrible, I know. Memory and multi-tasking definitely are affected. I think I have a thread about cognition stories a page or two back. This is something many Drs don't even mention but there are threads about it. One thread has a complete description on cognition. I think it's on a thread where I asked for help with my daughters college paper. That has the best description.