I have had many dozen seizures over the years. In one, I looked in mirror and half my face was gone. I also looked at a clock, and it was quickly spinning counter-clockwise. Not the same as dementia but it is amazing what the brain can do when not up to par.
I had a minor surgery. The first time I opened my eyes and sat up, I had serious double vision. They were going to move me. I said wait...I could feel my brain resolving it. Within a few minutes...it was gone...and never reoccurred. The brain is powerful. Dementia is a sad resolve.