When Ronald Reagan's physicians first suspected that the former President's memory lapses were caused by Alzheimer's disease, they had no easy way to confirm the diagnosis. To determine whether Reagan, now 83, had the degenerative brain disease that affects perhaps 4 million Americans, the doctors gave him a complex series of physical and psychological exams -- mainly to rule out other possible causes of his symptoms. A year passed before he was told that he was indeed in the early stages of Alzheimer's.
Now a group of researchers claim to have found a much easier method of detecting the disease. In...