The Smell Identification Test developed by the University of Pittsburg is a noninvasive and inexpensive test for Alzheimer’s disease. The instrument contains 40 items, and it can be self-administrated. The test provides an indication of smell loss and malingering.
The odor identification may be indeed linked to the way the brain and memory function, as the sense of smell, proved to be critical in neurogenesis and has strong associations with memory.
The results of the comparison between the two methods in elderly adults showed that a low score on the test was correlated with a positive amyloid beta status.
“Reduced ability to identify odors has been seen in patients who are later diagnosed with Alzheimer’s disease at autopsy. And decreased odor identification is also seen in those with mild memory symptoms and those who develop Alzheimer’s disease dementia,” said William Kreisl, a researcher at the Columbia University Medical Center in New York City.
The study involved 84 elderly participants from the Questionable Dementia II survey. They had either normal memory or mild cognitive impairment. The persons involved have been subjected to a lumbar puncture or a brain amyloid PET scanning one time during the admission and a second time six months after.
During the follow-up, 67% of the participants showed memory decline.
The respondents that had a low test score were three times more likely to have a memory decline than those with a score over 35.
People who were unable to detect and to identify odor also had a modification in the beta-amyloid status.
However, the scientists warn that the correlation between the Smell Identification Test and the amyloid procedure is not perfect. The odor test cannot be used as a replacement for the brain scan.
It seems that the smell sense works an indicator of cognitive decline, and the test developed by the University of Pittsburg could be used as a preliminary method of diagnosis the appearance of the disease.
The medical experts stress the fact that Alzheimer disease needs to be tested in a much simpler way because the brain scans are costly and not available for everyone it would need it. The researchers point out that finding a biomarker could be very useful in detecting the disease and preparing the treatment as early as possible.
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