My little experience with it, my great grandma was on her death bed, and when me and my dad came in to talk to her, she thought I was my dad and my dad was her son---and she kept saying she had to go see a friend at the trolly station near geary next to the theater...... (she grew up in San Fransisco in the 20's)...that was devastating---she said it was urgent and she really had to see him there----its amazing that something like that could linger in someones mind for so long...