Until recently, the only way to definitively diagnose Alzheimer's — America's sixth-leading cause of death — was through an autopsy.

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But recently, the U.S. Food and Drug Administration approved Amyvid, a new drug that may help doctors detect signs of the disease in the brain of live patients. The drug allows researchers to use imaging scans to detect amyloid plaque, the brain protein that is thought to be the telltale sign of the disease.

Michael Weiner, M.D., heads up the Alzheimer's Disease Neuroimaging Initiative (ADNI), which is currently conducting the largest clinical research study of Alzheimer's in the United States. With the help of Amyvid, his team's research could help diagnose Alzheimer's years before symptoms are displayed.

Despite more than 1,000 volunteers, including Weiner himself, ADNI is expanding its research by seeking new patients, both those with Alzheimer's and, especially, those with mild cognitive impairment.

Also of interest: 10 easy ways to keep your mind fit.