What is Alzheimer's?
Dr. Alois Alzheimer first identified the disease in 1906. He described the two hallmarks of the disease: "plaques", which are numerous tiny, dense deposits scattered throughout the brain that become toxic to brain cells at excessive levels, and "tangles", which interfere with vital processes, eventually choking off the living cells. When brain cells degenerate and die, the brain markedly shrinks in some regions.
The image below shows that a person with Alzheimer's disease has less brain tissue (right) than a person who does not have the disease (left). This shrinkage will continue over time, affecting how the brain functions.