Haha, leokitten forgot where s/he put her keys. I forgot which year it was, how to operate a vehicle as well as how to sign my signature.
"Brain fog" hardly describes our cognitive impairments does it? Losing things, losing words, losing concepts, losing abilities (like driving a car).... "brain fog" is a lot like "fatigue".
I, a (former) research engineer and college instructor, couldn't read a book or even an article because of focus problems (visual and mental) resulting from ME/CFS. That was a major trauma for me. My identity was built around my professional skill. Poof! Gone in a metaphorical instant.
Brain fog at that level is what put a number of us here out of work before the physical toll took over. No one wants an engineer, scientist, researcher, lawyer, whatever, who can't read and follow a page of text.
A lot of us have had to stop driving because of cognitive issues. Brain fog and it's associated cognitive brethren are a major nightmare of this illness that isn't talked about enough, imo.
I'm glad to say that Valcyte treatment (for HHV-6 in my case) improved the cognitive problems hugely. I can read a book and drive these days.
Unfortunately, a huge improvement is still not enough to make it as simple as it was pre-ME/CFS to read technical papers and the like.