text: Alzheimer's Disease is a FORM of dementia. There are other types.  It's a physical deterioration of the brain--the neurons are in "tangles" and covered with "plaque" (those are the scientific words) which is a geometrical progression downhill--as more neurons die and become tangles, the surrounding neurons can't communicate with any other ones, and they die too.\nIt is not DIRECTLY fatal like cancer is.  What happens is, as the person's brain deteriorates, that person forgets how to do more and more essential functions. Eventually AD patients forget how to eat and starve or choke or aspirate their food into their lungs (causing infection and death), or they forget to breathe and just die.  In the earlier stages a person can die through carelessness--forgetting to look both ways when crossing the street and getting hit by a car, or leaving a pan on the stove and burning down the house.\nIt's an awful terrible disease. My dad has it.