For Growdon's study, the researchers tapped 215 people from the Boston area who were between the ages of 64 and 88 and were participating in a research project designed to see whether results of brain scans are related to memory changes that occur in healthy older adults.
Participants received brain scans, genetic testing, blood and spinal fluid tests, and PET scans to detect amyloid plaques in the temporal lobe, an area important for memory. They also took a smell identification test known as the University of Pennsylvania Smell Identification Test (UPSIT) and a comprehensive set of tests to measure thinking skills.
"This research shows that the UPSIT/odor identification testing could theoretically be an affordable and quick screening test that could be followed up by more expensive, involved and accurate tests such as PET scans or cerebral spinal fluid studies," Growdon said.
The second study, led by Dr. Davangere Devanand, a professor of psychiatry and neurology at Columbia University Medical Center in New York City, found that among 757 participants, lower scores on the UPSIT smell test were associated with the transition to dementia and Alzheimer's disease.
Authors of both studies cautioned that their results were simply a snapshot in time, and larger studies that follow people over a longer period of time would be necessary to confirm the findings.
Dr. Kenneth Heilman, a professor in the department of neurology at the University of Florida College of Medicine in Gainesville, cautioned that many conditions can interfere with the sense of smell, including unclear nasal passages, allergies, nasal septum (nose structure) defects, Parkinson's disease, exposure to fumes and toxins, some medi
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