I remember going through this with my first childhood cat when I was 24 and she was 19. I was very glad that there was almost always someone in the house with her during that time. She was such a loving cat.

On the other end of the scale, Kyoko (who is four) has been circling my room for the last 15 minutes, meowing loudly at invisible bugs. ...In her case, I'm not sure it will be possible to become any more senile than she already is :P She is my most foolish, but most adorable cat.