A study by Columbia Mailman School of Public Health investigator Dr. Seonjoo Lee, assistant professor of biostatistics, and colleagues reported that an odor identification test may prove useful in predicting cognitive decline and detecting early-stage Alzheimer’s disease. The study was presented by Dr. Lee at the Alzheimer’s Association’s International Conference in Toronto, Canada.
[Photo: Dr. Seonjoo Lee]
The researchers administered the University of Pennsylvania Smell Identification Test (UPSIT) to 397 older adults (average age of 80 years) without dementia from a multiethnic population in northern Manhattan. Each of the participants also had an MRI scan to measure the thickness of the entorhinal cortex — the first area of the brain to be affected by Alzheimer’s disease.
Four years later, 50 participants (13 percent) had developed dementia, and nearly 20 percent had signs of cognitive decline.
The researchers found that low UPSIT scores, but not entorhinal cortical thickness, were significantly associated with dementia and Alzheimer’s disease. Low UPSIT scores indicate decreased ability to correctly identify odors. Low UPSIT scores, but not entorhinal cortical thickness, also predicted cognitive decline, although entorhinal cortical thickness was significantly associated with UPSIT score in those who transitioned to dementia.
“Our research showed that odor identification impairment, and to a lesser degree, entorhinal cortical thickness, were predictors of the transition to dementia,” said Dr. Lee. “These findings support odor identification as an early predictor, and suggest that impairment in odor identification may precede thinning in the entorhinal cortex in the early clinical stage of Alzheimer’s disease.”
The results also suggest that the smell identification test may offer a practical, low-cost alternative to other tests and adds to the growing body of evidence demonstrating the potential value of odor identification testing in the detection of early-stage Alzheimer’s disease, according to the authors.
“Predictive Utility of Entorhinal Cortex Thinning and Odor Identification Test for Transition to Dementia and Cognitive Decline in an Urban Community Population,” was funded by the National Institute on Aging, grants K01AG051348, R01AG034189, R01AG037212, K99/R00AG042483, R01AG041795.