Early detection of Alzheimer’s may start in the eyes or nose, not in the brain. This conclusion is the result of several new research studies that were reported during the week of July 12-17, 2014 at the Alzheimer’s Association International Conference® 2014 (AAIC® 2014) in Copenhagen.
Researchers at the Harvard Aging Brain Study used the University of Pennsylvania Smell Identification Test (UPSIT) to study the ability of 215 healthy participants with no memory loss to recognize familiar smells. UPSIT consists of 40 scratch-and-sniff panels with different odors.
The study participants were also given standard tests for Alzheimer’s including cognitive evaluations and positron emission tomography (PET) scans. The PET scans measured the presence of deposits of beta-amyloid plaque in the brain.
Beta-amyloid is a protein known to accumulate in the brain in people who have Alzheimer’s. Researchers believe the plaque blocks the transfer of electrical signals between brain cells.
The study showed that patients who scored lower on the odor recognition test also had higher levels of beta-amyloid in the brain. The researcher team intends to follow the patients over an extended time to continue the study.
Researcher Davangere Devanand, MBBS, MD and professor of Psychiatry, and colleagues at Columbia University Medical Center also studied the connection between odor detection and Alzheimer’s.
Between 2004 and 2006 they administered UPSIT to 1037 elderly people living in New York City who did not have dementia at the start of the study. They conducted other tests on the group in three cycles concluding in 2010.
Devanand reported at AAIC® 2014 that for the 757 patients who were followed throughout the study, lower scores on UPSIT were significantly related to a transition to dementia and Alzheimer’s.
"If further large-scale studies reproduce these results, a relatively inexpensive test such as odor identification may be able to identify subjects at increased risk of dementia and Alzheimer's disease at a very early stage, and may be useful in identifying people at increased risk of cognitive decline more broadly," Devanand said.