boston.com your connection to The Boston Globe

New tests predict Alzheimer's victims

Researchers use blood, brain scans to detect signs

WASHINGTON -- New tests involving blood and brain scans can detect symptoms of Alzheimer's disease, and brief appraisals of real-life functioning can predict who is likely to develop it, researchers said yesterday

The tests will be critical, specialists told a meeting on Alzheimer's disease, because more than 26 million people have the brain-wasting disease and that number will quadruple to 106 million by 2050.

"By 2050, 1 in 85 persons worldwide will have Alzheimer's disease," said Ron Brookmeyer of Johns Hopkins University. He led the study on how many people have the disease.

No drugs can affect Alzheimer's disease significantly, although four have a modest impact if given early on.

The disease is difficult to detect until it has progressed from mild memory loss to clear impairment. Patients eventually lose all ability to care for themselves.

Detecting the disease early can help patients and their families plan better for the future. Early detection can also help researchers develop drugs to treat and perhaps even prevent the disease.

Anders Lonneborg and colleagues of DiaGenic, a biotech company based in Oslo, found a set of 96 genes that look different in the blood of Alzheimer's patients. Their study of more than 100 older people, half from memory clinics and half from senior centers, found Alzheimer's accurately 85 percent of the time.

They identified genes related to the immune system, to inflammation, and to cell division. The company has applied to regulators in the United States and Europe to approve the test, Lonneborg told a meeting of the Alzheimer's Association in Washington.

Christos Davatzikos and colleagues at the University of Pennsylvania used a combination of PET and MRI scans to diagnose Alzheimer's. PET -- positron emission tomography -- scans can be used to measure blood flow in real time, while MRIs -- magnetic resonance imaging -- can clearly show the shape and size of physical structures in the brain.

This method correctly found all 15 cases of mild cognitive impairment -- a first step toward Alzheimer's -- and cleared 15 healthy volunteers. "This abnormal pattern of brain structure and blood flow detected not only mild cognitive impairment but even earlier . . . when they were clinically normal," Davatzikos told the news conference.

Deborah Barnes and colleagues at the University of California, San Francisco, developed a more low-tech approach that might be used by a family doctor.

SEARCH THE ARCHIVES