Has anyone know some one with, or know what causes sudden memory loss? My father is 57 years old and yesterday was working on his boat when all of a sudden he could not remember who he was or what he was doing.  My sisters husband who was with him said that nothing had happened.  He was sitting down talking when he just could not remember.  So of course they took him to the hospital where they hooked him up to a heart monitor.  They thought that maybe he had a stroke but his they found his heart was healthy.  So they did a MRI, then cat-scan.  Found nothing.  He has since regained all his long term memory but cant take on any new ones.  He forgets everything in 2 minutes.  Its like 50 first date.  Except she had 24 hours.  He only has 2 mins.

Summarized question: Has anyone know someone with, or know what causes sudden memory loss?