What is Alzheimer's disease?

Have started reading on Alzheimer's disease. Mum-in-law seemed to be suffering from this disease.

Some facts I just learned:-
1. It is a type of dementia. Brain cells start dying
2. Patient lost ability to solve problem and grasp concept
3. It is harder to form new memory
4. Patient lost control over mood
5. Patient starts to lose precious memory
6. Affect its bodily function
7. It is a slow fatal disease affecting the brain;takes about 8 to 10 years.