The entertainer, Andy Williams, tells a great story (my friend Dan relayed the story to me).
He went to see someone at a nursing home who was in a dementia unit.
While waiting for the person he struck up a conversation with an elderly women, in the garden area, who was also a resident of the nursing home dementia unit.
After conversing for awhile, Andy Williams asked the women, "do you know who I am?"
"No," she replied, "you'll need to ask the women at the front desk...she might know."