Multiple studies suggest having a poor sense of smell and sight increases one's risk of developing Alzheimer's disease in just a few years.
Lead author Matthew E. Growdon, along with researchers from the Harvard Medical School and Harvard School of Public Health conducted two studies to find out whether sense of smell and sight can be used to predict Alzheimer's disease. In the first study, researchers found out the ability to recognize odors was closely related to the function of the brain affected by dementia. During the second study, analysts were able to link the amount of beta-amyloid found in the eye to beta-amyloid levels in the brain.
Growdon explained the onset of Alzheimer's kills brain cells, which in turn impairs the person's ability to smell and see.
The studies involved 215 healthy participants who filled out a standard 40-item exam to measure their cognitive abilities. The results of their exams were then compared to the participant's brain structures in their temporal lobes. Researchers observed that those who got poor scores in the exam also had smaller hippocampuses and thinner entorhinal cortexes, which were both indicators of poor sense of smell and sight.
"Our research suggests that there may be a role for smell identification testing in clinically normal, older individuals who are at risk for Alzheimer's disease," Growdon said.
Meanwhile, Davangere Devanand, professor of Psychiatry (in Neurology and in the Sergievsky Center) at Columbia University Medical Center, and his team conducted a similar study involving 757 participants from different ethnicity. Their probe focused on the sense of smell which obtained a similar result with Growdon's study.
"Odor identification deficits were associated with the transition to dementia and Alzheimer's disease, and with cognitive decline in cognitively intact participants, in our community sample. The test was effective in both English and Spanish," Devanand stated.
These studies were presented at the Alzheimer's Association International Conference held in Copenhagen, Denmark.
