You sure it isn't yours?

I have been lucky so far in my life that no one very close to me has had this problem, yet, although my husband's grandfather is obviously starting down this path. The last time we saw him, he overheard us telling someone else where we lived. He then proceeded to ask us if we knew ourselves, because for a moment he had lost track of who we were. Very heartbreaking.

One other experience I had was quite odd. My then-husband and I had just purchased a new house. Our first meeting with the next door neighbor he kept asking us if we'd bought the car. We were utterly confused, until other things in the conversation made us realize he wasn't quite all there, and it eventually became clear he was trying to ask us if we bought the house. I don't know if this sort of substituting the wrong word is common; it isn't what they show in movies.