Researchers in Japan and Australia say they have made progress in developing blood test that could one day help doctors identify who might get Alzheimer’s disease. The scientists said the test can recognize a protein known as amyloid (涛粉样蛋) beta, which other studies have linked to Alzheimer's. They said it was correct more than 90 percent of the time in a study involving over 370 people. The findings were published in the journal Nature.

Alzheimer's disease is the most common form of demenna（痴呆). Experts believe dementia affects close to 50 million people worldwide. By the year 2050, it is expected to affect more than131 million people. Those numbers come from Alzheimer's Disease International, a non-profit group. Currently, doctors have two ways to identify a buildup of amyloid beta in the brain. One is brain scan or brain imaging; the other is a spinal tap(脊椎抽 液). But both tests are invasive,costly and may only show results when the disease has already started to progress. There is no treatment that can slow the progression of Alzheimer's. Current drugs can only case some of the effects of the disease.

Having a simple, low-cost blood test could make it easier for drug companies to find enough people who are at risk of developing Alzheimer's to test new medicines, said Katsuhiko Yanagisawa. He was one of the leaders of the study. He works at the Japanese National Center for Geriatrics and Gerontology

Alzheimer's disease is thought to start developing years before patients have any signs of memory loss. Experts say an important factor in finding an effective treatment will be the ability to recognize signs of the disease early. "You have got to walk before you run, "said Colin Masters, a co-leader of the study and a professor at the University of Melbourne in Australia. " You have to learn to diagnose the disease directly before you can hope to see the effect of therapeutic intervention. And that’ s where the real value in this test will come. " Masters added.

This passage reports the development of a__________ test to diagnose Alzheimer's disease

One advantage of the present test is that it costs__________ than the previous tests.

All the three tests identify Alzheimer’s disease by detecting a protein named__________.

Can doctors cure or slow down the progression of Alzheimer’s disease today?

Alzheimer's disease may have already started before patients have any signs of memory__________.