FRIDAY, July 29, 2022 (HealthDay News) — Could the future of dementia screening include testing a person’s sense of smell?

He can, suggests a new study who found a decline in a person’s sense of smell could predict their loss of mental function and warn of structural changes in the brain that are important in Alzheimer’s disease.

“This study provides another clue to how a rapid decline in smell is a very good indicator of what will end up happening structurally in specific regions of the brain,” said co-author Dr. Jayant Pinto, a professor of surgery at the University of Chicago and an ear, nose, and and throat.

That there is a link between smell and dementia is not new information. The plaques and tangles that occur in Alzheimer’s disease often appear in areas of the brain associated with smell and memory before appearing in other parts of the brain, the study authors noted. . Researchers don’t know if this damage causes the sense of smell to decline.

For this study, the investigators sought to determine whether it was possible to identify brain alterations correlated with a loss of smell and mental disorders, or cognitiveoperate over time.

“Our idea was that people whose sense of smell declined rapidly over time would be worse off — and more likely to have brain problems and even Alzheimer’s disease itself — than people who declined slowly or maintained a normal sense of smell,” Rachel said. Pacyna, a fourth-year medical student at the University of Chicago Medical School and lead author of the study.

The research team used data on 515 older adults from Rush University’s Memory and Aging Project (MAP).

Researchers test MAP volunteers each year for their ability to identify certain smells, for mental function and for signs of dementia. Some participants also received an MRI.

The study team found that the rapid decline in smell during a period of normality predicted smaller gray matter volume in areas of the brain related to smell and memory. It also predicted a deterioration in mental functioning and a higher risk of dementia in these older people.

The risk was similar to carrying the APOE-e4 gene, which is already a known genetic risk factor for developing Alzheimer’s disease, the team explained in a university press release.

The researchers also found that the changes were more visible in the primary olfactory regions – regions related to smell – including the amygdala and the entorhinal cortex. This is a major contribution to seahorsecritical site of Alzheimer’s disease.

“We were able to show that the volume and shape of gray matter in the olfactory and memory-associated areas of the brain of people with rapid decline in their sense of smell were smaller than those of people with less severe olfactory decline,” Pinto said.

The study was limited in that participants received only one MRI, so the team could not determine when structural changes in these brains began.

“We have to take our study in the context of all the risk factors we know about Alzheimer’s disease, including effects of diet and exercise“, Pinto said. “The sense of smell and the change in the sense of smell should be an important element in the context of a range of factors that we believe affect the brain in health and aging. .”

Another limitation is that the participants were only white adults. The team’s previous work had shown marked disparities by race.

More than 6 million Americans have Alzheimer’s disease, for which there is no cure. Some medications can temporarily slow symptoms.

The results were published online July 28 in Alzheimer’s and dementia.

The US National Institute on Aging has more information on Alzheimer’s disease.

SOURCE: University of Chicago Medical Center, press release, July 28, 2022