CHICAGO, Jan. 22 (Xinhua) -- Researchers at Washington University School of Medicine have engaged in a long-term study of adult children of Alzheimer's patients, aiming to define who is likely to develop the disease and when, and to establish a timeline for how quickly the disease will progress.

The study, which began in 2005, already has helped identify some of the molecular and structural changes in the brain that occur in the decades before a person is diagnosed with the neurodegenerative disease.

The Adult Children Study recruits and follows people aged 45 to 74 who have no problems with memory or thinking. Most participants are at elevated risk for developing Alzheimer because one or both of their parents has or had the disorder. Adult children with parents who were never diagnosed with the disease serve as a comparison group.

The study follows both groups over time, measuring participants' memory and thinking skills, as well as taking scans of their brains and measuring levels of key Alzheimer's proteins as the people in the study age.

The study participants regularly come to Washington University's Knight Center to undergo memory and cognition tests.

Once every three years, participants undergo brain scans to determine the size, thickness and connections between different parts of their brains, and to locate clumps of toxic Alzheimer's proteins.

The participants also undergo a spinal tap to measure levels of amyloid beta and tau in their cerebrospinal fluid, as well as levels of other proteins associated with neurologic damage and inflammation.

"If you knew that you were at high risk to develop Alzheimer's dementia in the next few years, you might make some changes to your life," said Tammie Benzinger, an associate professor of radiology who directs the imaging studies in the Knight Center. "You might choose to move to an independent-living environment that also provides nursing care. You might choose to move closer to your children."

Further, people who currently are healthy but at increased risk to develop Alzheimer's disease represent an ideal population to test preventive therapies. It is possible that drugs have failed to demonstrate benefit in the past because they were tested in people who already had an Alzheimer's diagnosis. People with symptoms severe enough for diagnosis already would have sustained profound damage to their brains.

The goal of the study is to catch people on their way to developing Alzheimer and intervene so they never get there.