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Gary Campbell, garycamp@asu.edu
(480) 965-7209
August 9, 2002

Study links gene, brain abnormalities

Decades before clinical symptoms occur, researchers can find decreased levels of brain activity in individuals with increased genetic risk for Alzheimer's disease, according to a new study by a team that includes an ASU associate research professor.

The team, which includes researchers from Good Samaritan Regional Medical Center and the Mayo Clinic Scottsdale, and Gene Alexander, an associate research professor in psychology at ASU, presented its research July 24 at the eighth annual International Conference on Alzheimer's Disease and Related Disorders.

The researchers studied young adults in their 20s and 30s who are carriers of the apolipoprotein E e4 (APOE e4) gene, considered a susceptibility factor for late-onset Alzheimer's, using a brain imaging technique called Positron Emission Tomography (PET). PET shows the brain's use of glucose, considered a fuel for the brain, and can show areas of diminished brain activity.

In the study, 12 individuals with the gene showed no outward cognitive deficits but based on the PET scans had certain areas of decreased brain activity, similar to that of patients with Alzheimer's dementia. A control group of 15 individuals without the gene showed no similar decreases.

"This shows a reduction in brain activity decades before clinical symptoms typically occur," says Alexander, who analyzed data from the scans. "It's important because it gives us a way to evaluate the very early effects of Alzheimer's, many years before the onset of cognitive decline and potentially provides a way to evaluate prevention therapies."

Alexander says the research follows previous work that showed diminished brain activity in cognitively normal older carriers of the APOE e4 gene. The technique also identifies reductions in brain activity in those who have been clinically diagnosed with the debilitating cognitive disorder of Alzheimer's dementia.

Alexander says the research does not show how likely any one individual is to develop Alzheimer's in the future. The APOE e4 gene is found in about 25 percent of the population and is present in many, but not all Alzheimer's patients.

"All of the individuals in this study are cognitively normal," he says. "More research is needed to understand how these early brain changes progress over time and how they relate to cognitive symptoms when Alzheimer's dementia develops."

The study is part of the continuing work by Alexander and his colleagues as part of the Arizona Alzheimer's Research Center, supported by grants from the National Institutes of Health, the Alzheimer's Association and the state of Arizona.

Campbell, with Media Relations & Public Information, can be reached at (480) 965-7209 or (garycamp@asu.edu).