Scientists have been looking hard for a way to slow the inevitable march of Alzheimer's disease, which progresses from minor memory impairment to total loss of brain functioning and death. There is currently no cure for the disease and though certain drugs seem to mitigate it, the 4.5 million Americans afflicted are still without much hope of living a normal, unassisted life. A group of researchers from the Mayo Clinic looked at whether or not a drug could slow the progression of Alzheimer's.

What the researchers wanted to know: Could an Alzheimer's drug called donepezil slow the progression from mild cognitive impairment, a harbinger of the disease, to full-blown Alzheimer's?

What they did: The study was carried out at treatment centers around the country with 769 patients split up into three groups. The first group took donepezil everyday, the second took Vitamin E, which has been shown to slow the onset of Alzheimer's, and the third group was given a placebo. All of the subjects tested positive at the beginning for mild cognitive impairment and were given a number of cognitive tests and questionnaires every six months after that for three years to test whether they had progressed to Alzheimer's.

What they found: Overall, 13 percent of the patients in the trial developed Alzheimer's after three years. However, donepezil and, to a smaller extent, Vitamin E both delayed its onset. On average, subjects taking the placebo developed Alzheimer's 484 days after they were first tested for mild cognitive impairment, subjects taking Vitamin E took 540 days to develop the disease, and subjects given donepezil tested positive for Alzheimer's after 661 days.

What it means to you: By the end of the three-year study, the percentage of people who had developed Alzheimer's was the same for all three groups. However, according to the lead researcher, this is the first study to demonstrate a way to delay the onset of the disease and could lead to ways to keep people functioning and healthy longer.

Caveats: The study was presented at the International Conference on Alzheimer's Disease in Philadelphia on July 17-22; it has not yet been reviewed by other experts on Alzheimer's and donepezil is still a long way from being approved for preventive use by the Food and Drug Administration. (But doctors are allowed to prescribe drugs for uses they weren't originally approved for.)

Find out more: The Alzheimer's Association, which sponsored the conference where this study was presented, has a good deal of information about the disease, preventions, and treatments.

Read the article: There's no article to read yet, because these results are from a medical conference. The lead researcher, neurologist Ronald Petersen, works at the Mayo Clinic and will likely publish soon.