Researchers have discovered changes that take place in the
brains of people who have Alzheimer's disease. These brain
changes may cause the memory loss and decline in other mental
abilities that occur with Alzheimer's disease. It's not fully
understood why these brain changes occur in some people but not
in others. Alzheimer's disease gets worse over time, but the
course of the disease varies from person to person. Some people
may still be able to function relatively well until late in the
course of the disease. Others may lose the ability to do
everyday activities very early on. - The disease tends to get
worse gradually. It usually starts with mild memory loss. It
progresses to severe mental and functional problems and eventual
death. - Symptoms sometimes are described as occurring in early,
middle, and late phases. It's hard to predict how long each
phase will last. - The average amount of time a person lives
after developing symptoms of Alzheimer's disease is 8 to 10
years. A person with severe dementia b