Low Scores on Odor Identification Test May Predict Early-Stage Alzheimer’s Disease

At the 2016 Alzheimer’s Association International Conference yesterday, new evidence was presented suggesting that a low-cost smell identification test may be able to predict cognitive decline and the early onset of dementia in older adults.

Past studies have suggested that decreased ability to identify odors is a predictor of cognitive decline. The current study, led by researchers from the Columbia University Medical Center and New York State Psychiatric Institute, evaluated the usefulness of the 40-item University of Pennsylvania Smell Identification Test (UPSIT) in detecting the transition to dementia and cognitive decline. 

The researchers administered UPSIT to 397 older adults (average age of 80 years) from a multiethnic population in Manhattan, New York, who did not have dementia at the start of the study and were followed for four years. All participants received an MRI scan to measure the thickness of the entorhinal cortex, one of the first regions of the brain known to be affected by Alzheimer’s disease. Composite cognitive domain scores were derived from memory, language, and visual-spatial abilities.  

At the four-year follow-up, 12.6% of the participants had developed dementia, and 19.8% had signs of cognitive decline. Low UPSIT scores—indicative of a decreased ability to identify odors—and entorhinal cortical thinning were significantly associated with the transition to dementia after adjusting for age, education, gender, language of UPSIT administration (English or Spanish), functional status, and intracranial volume. Low UPSIT scores also predicted cognitive decline; entorhinal cortical thinning was not associated with cognitive decline.

“It’s clear that the science around biological measures in the detection of Alzheimer’s continues to gather pace and validation,” said Heather Snyder, Ph.D., director of medical and scientific operations of the Alzheimer’s Association, at a press conference that highlighted the study’s findings. “Using other biomarkers of Alzheimer’s disease to detect the disease at an earlier stage—which have the potential to be lower-cost and non-invasive—could lead to dramatic improvements in early detection and management of the disease.”

For more information, see the Psychiatric News article “Low Physical Activity in Early Adulthood Linked to Worse Midlife Cognition.”