A study of older adults in China offers a closer look at the dominolike sequence of brain changes that lead to Alzheimer's. Scientists don't know exactly how Alzheimer's forms but it quietly ravages the brain long before symptoms appear. Compared with people who remained healthy, researchers spotted differences in a sticky protein named amyloid 18 years before Alzheimer's patients were diagnosed. Other so-called biomarkers appeared every few years afterward. Experts say understanding the timeline of brain changes will help with testing new treatments or preventive therapies. The findings were published Wednesday in the New England Journal of Medicine.
