What causes a person with dementia suddenly forget who she is & name of person speaking to but within 15 minutes remembers names again?

My fathers mind was a continuous loop, and he was not diagnosed with dementia. Me, I am 72 and sometimes is takes me a minute to regain something.

Hasn't happened to you yet, huh? I am 77. Has happened. It is stored there somewhere, but the harder you try to get through the weeds to it, the harder it is to find. Can't remember an actor's name one second, or a Social Worker I used to work with daily....then am out on the bus and it comes right into my head out of the blue. The brain is an amazing mystery. My brother has early onset Lewy's and is rational with good long and short term memories, but the things he sees, and the ways in which he can describe them to me are amazing. He says he has to work "backward" from what he thinks he sees initially, if that makes any sense; it does when he tells it. Oliver Sacks, before he died, wrote amazing essays about the brain. Try his early Awakenings or see the film with DeNiro, or read his later essays on Alzheimer's and dementia. The same goes for children on the Autism spectrum. The brain is utterly amazing, and while this may not be your world, or the "normal" world, it IS a whole world.

WillyB, in my humble opinion, the brain goes around in the loop, so after awhile that person's brain is back in the here and now.