Poor sense of smell may be a sign of Alzheimer's disease

According to a large-scale study by US scientists, people who have difficulty perceiving common odors, such as onions, lemons, and cinnamon . may be the first sign of Alzheimer's disease. The new finding could help shape olfactory testing methods to determine the risk of Alzheimer's disease - the fourth leading cause of death for the elderly.

Alzheimer's is a neurodegenerative disease that causes dementia in the elderly. This disease gradually destroys memory as well as the ability to think, realize, communicate and daily activities.

In this study, 600 people aged between 54 and 100 were required to distinguish 12 familiar smells: onion, lemon, cinnamon, black pepper, chocolate, rose, banana, pineapple, soap, paint thinner, Gasoline and smoke. When sniffing each of the aforementioned smells, the test participant listened to the questions that were read aloud and then selected one of the four answers to the smell name written on a piece of paper.

Test results show that in the total number of people above, 25% have correctly identified all odors or only one mistake at a time; 50% smell right at least 9 odors; and the remaining 25% only recognize 8 smells or less.

All 600 people were tested for cognitive function 21 times a year for five years, and one-third of them had at least one mild memory and thinking disorder.

The weak sense of smell can be an early sign of Alzheimer's disease (Photo: abc.net.au)

In those who commit at least four errors in odor tests, the risk of cognitive disorders increases by 50% compared to those who commit no more than 1 error. People who distinguish bad smell also have a higher risk of developing Alzheimer's disease from mild defects of cognitive function.

After eliminating the effects of factors such as age, gender, education, history of stroke and smoking, experts found that the test results remained unchanged: those who were less capable of The identification of odors will have a higher risk of cognitive disorders.

According to scientists, microscopic lesions are considered to be the first sign of Alzheimer's disease in the brain region that controls the sense of smell.

Therefore, the team believes that olfactory testing may be an important tool for early detection of this disease, thereby finding ways to slow or stop the development of the disease as well as severe dementia. caused by disease.

Commenting on the study, Robert Franks, a University of Cincinnati brain and odor expert, said: 'This research is significant because it is based on anatomically.'

According to him, other studies have also shown that the ability to smell smells is linked to Alzheimer's disease, but this is the first study of the sense of smell of healthy people for 5 years with many practical tests. to detect signs of dementia.

The lead researcher, Dr. Robert Wilson, of the Rush University in Chicago, argued that he should not be alarmed by the weakening of the olfactory ability. He said: 'Not everyone who distinguishes bad smells has cognitive trouble.'

Claire Murphy, Alzheimer's expert at San Diego State University, also advised elderly people to inform their doctors about losing their ability to recognize odors. Weakness in the sense of smell like that can come from a mass of excess flesh (polyps) in the nose or sinusitis. She said: 'If an elderly person still has a delicate sense of smell, that is a very good sign for cognition.'

This study was conducted with funding from the US National Institute of Aging Research and Illinois State Department of Public Health.

The results of Dr. Wilson and his colleagues were published on July 2, 2007 on Archives of General Psychiatry in the United States.

Quang Thinh