The decreased sense of smell of a person over time can not only predict loss of cognitive function. Its rapid decline – a sudden loss of sense of smell – may be a predictor of structural changes in brain regions that are important for the development of Alzheimer’s disease and dementia in general.
This is the main conclusion of a survey conducted by the University of Medicine of Chicago. It offers “another clue“How a rapid decline in the sense of smell is a “really good” indicator of what is going to happen structurally in specific regions of the brain, summarizes Jayant M. Pinto, one of its authors. Based on a follow-up study of 515 elderly people, it is published in Alzheimer’s and dementia: the journal of the Alzheimer’s Association.
The Memory plays a fundamental role in the human ability to recognize odors and the scientific community has known for a long time the relationship between the sense of smell and dementia, recalls a press release from the University of Chicago collected by the EFE agency.
The ace protein plaques and tangles that characterize the tissue affected by Alzheimer’s disease generally appear in the olfactory areas of the brain and those associated with memory before developing in other parts of this organ. However, it is still unclear whether this damage is the cause of a person’s diminished sense of smell.
Pinto and his team wanted to see if it was possible to identify brain alterations correlated with a person’s loss of sense of smell and cognitive function over time.
“Our idea was that people whose sense of smell declines rapidly over time would be less fit – and more likely to have brain problems and even Alzheimer’s disease – than those whose sense of smell declines rapidly over time. slowly decreased or kept a normal sense of smell“, details Rachel Pacyna.
The team used anonymous patient data from the Memory and Aging Project from Rush University, began in 1997 to study chronic conditions of aging and neurodegenerative diseases, such as Alzheimer’s disease.
Patients undergo annual tests to test your ability to identify certain smells, your cognitive function or signs of dementia. Some also had an MRI.
In their observations, the scientists found that a rapid decline in a person’s sense of smell during a period of normal cognition predicts multiple hallmarks of Alzheimer’s disease, including decrease in gray matter volume in areas of the brain related to smell and memory, lower cognition and increased risk of dementia.
In fact, the risk of losing the sense of smell was similar to that of carry the APOE-e4 genea known genetic risk factor for developing Alzheimer’s disease. The changes were most noticeable in the primary olfactory regions, including the amygdala and entorhinal cortexwhich is an important contribution to the seahorsea critical site for the development of Alzheimer’s disease.
“We were able to show that the volume and shape of gray matter in olfactory and memory-associated areas in people with rapid decline in smell was lower compared to those with less severe olfactory decline,” summarizes Pinto. According to the researcher, this study “must be taken in the context of all known risk factors for Alzheimer’s disease, including the effects of diet and exercise“.
“The sense of smell and its changes should be an important element in the context of a number of factors that we believe affect the brain in health and aging.” For Pacyna, if one could identify people in their 40s, 50s, and 60s who are most at risk earlyyou might have enough information to enroll them in clinical trials and develop better drugs.
However, the scientists admit some limitations of the study, such as the fact that the participants only had an MRI scan, therefore lacking data to determine when structural changes in the brain began or how quickly the brain regions have shrunk.