>Dementia/alzheimers/etc is one of the scariest things i can imagine. I'm not sure i would want to live if i had the later stages of that, or if you can even call that living.

ok but it is not a 100% case that the mind of a 90 year old is the mind of an Alzheimer's patient. Michael Caine is 88 and I think he is doing relatively well mentally.