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2014 Grants - Risacher
Visual Dysfunction and Amyloid in Preclinical and Prodromal Alzheimer’s Disease
Shannon L. Risacher, Ph.D.
2014 New Investigator Research Grant
Because Alzheimer's disease is a progressive disorder, researchers are seeking ways to better diagnose the disease at its earliest stages — before clinical symptoms appear. One part of the body, the retina of the eye, may develop changes indicative of “preclinical” Alzheimer's. Such changes include the build-up of a protein fragment called beta-amyloid. Clumping of beta-amyloid in the retina may lead to visual disorders associated with Alzheimer’s. It may also indicate similar clumping in the brain, which is a hallmark of Alzheimer’s disease and thought to promote early changes that lead to dementia-related brain cell damage and death.
In preliminary studies of people with Alzheimer’s disease and other forms of cognitive impairment, Shannon L. Risacher, Ph.D., and colleagues found an association between beta-amyloid deposits and reduced “contrast sensitivity” (or the ability to distinguish between fine elements of light and dark in one’s environment). For their current work, the research team will study individuals with healthy brains and people with early declines in brain function called “subjective cognitive decline” and “mild cognitive impairment.” Both conditions may eventually lead to Alzheimer’s disease. Dr. Risacher and colleagues will determine whether contrast sensitivity problems are directly related to beta-amyloid accumulation in the retina. They will then use brain imaging techniques to assess whether these retinal changes are linked to Alzheimer’s-related changes in the brain —including beta-amyloid clumping, changes in brain cell connections and brain cell loss.
The results of these studies could increase our understanding of how detectable changes in the eye may indicate early changes in the brain and lead to novel, non-invasive tools for early detection of cognitive decline and Alzheimer’s disease.