Recent research suggests that a brain affected by Alzheimer's disease looks very different from one undergoing normal aging. While all brains shrink in volume as we get older, Alzheimer's brains lose even more volume than healthy brains. Understanding these differences could lead to better ways to diagnose the disease earlier, even before symptoms appear.By the time Alzheimer's is well-established, there are distinct differences between an affected brain and one that is aging normally, say experts. But increasingly, they believe it's important to identify those who are in the early stages of disease, so they might benefit from lifestyle interventions, such as keeping their brains active, that might slow down the progression of Alzheimer's.