My father’s mother and my husband’s maternal grandmother both passed away last year.  They suffered from dementia and Alzheimer’s, respectively.  It was just as painful for me to watch my grandmother waste away into a shadow of her former self as it was to have the same conversations with my husband’s grandmother knowing she would never know me for more than minutes at a time.  I got that same sadness to a lesser degree while reading Sir Terry Pratchett’s latest Discworld book.