A sudden loss of smell can be a sign of DEMENTIA

A sudden loss of smell has become a symptom of Covid, but scientists warn it could be an early sign of dementia.

Studies have previously linked the gradual loss of smell to memory loss.

But new research suggests that rapid deterioration may be a good indicator.

American scientists followed more than 500 elderly people in the United States for 20 years.

Those who experienced anosmia for several years were almost twice as likely to develop Alzheimer’s disease as those who lost their sense of smell for decades.

Professor Jayant Pinto, a senior researcher at the University of Chicago, said it was “another hint” of a link between smell and dementia.

He suggested doing smell tests like hearing and vision tests for older people to check for disease.

American scientists who followed more than 500 older adults found that those who experienced a sharp decline in their sense of smell were more likely to develop Alzheimer’s disease or dementia than those who lost it gradually.



Dementia is an umbrella term used to describe a range of progressive neurological diseases (those affecting the brain) that affect memory, thinking and behaviour.

There are many types of dementia, of which Alzheimer’s is the most common.

Some people may have a combination of dementia types.

Regardless of the type of diagnosis, each person experiences their mental disability in their own way.

Dementia is a global problem, but it is more common in wealthy countries where people live to a very old age.


More than 900,000 people in the UK today have dementia, according to the Alzheimer’s Society. This should increase to 1.6 million by 2040.

Alzheimer’s disease is the most common form of the disorder, affecting 50 to 75 percent of those diagnosed.

In the United States, the number of people with Alzheimer’s disease reaches 6 million. A similar percentage increase is expected in the coming years.

As a person ages, so does the risk of dementia.

Although diagnosis rates are improving, many people with dementia are still thought to be undiagnosed.


There is currently no cure for dementia.

But new drugs can slow its progression, and the earlier it’s detected, the more effective the treatment.

Source: Alzheimer Society

Although the sense of smell is often considered less important than the senses of sight and hearing, it provides important information to the brain.

Memory plays an important role in recognizing smells, and researchers have long known the link between the smell and cognitive decline.

Research shows that “tangles” of amyloid protein in the brain — a hallmark of dementia — often occur in areas of the brain associated with smell and memory.

However, it is not yet known whether this damage actually causes a person’s sense of smell to decline.

Professor Pinto and his team wanted to investigate whether these changes were linked to the loss of smell and brain function over time.

Rachel Pacina, a researcher at the university, said: “We think that people who experience a rapid decline in their sense of smell will fare worse over time and are more likely to develop brain problems and even Alzheimer’s disease than people who have a gradual decline or maintain a normal sense of smell.’

For 20 years, the researchers monitored 515 people in their seventies who initially had no dementia or cognitive problems.

The volunteers all lived in nursing homes and were tested annually on their ability to identify certain smells and signs of dementia. Also include MRI scans.

Their olfactory decline was measured by their scores on olfactory tests, which were then graphed. The downward trend in the slope is marked as “strong”, “decreasing”, “unchanged” or “improved”.

About 100 of the cohort were diagnosed with dementia or cognitive impairment.

Those who did not have the classic symptoms of Alzheimer’s but experienced a rapid loss of sense of smell were 89 percent more likely to have memory-impairing conditions than those who lost their sense of smell more slowly.

Sudden loss of smell is also associated with an increased risk of shrinking gray matter in the parts of the brain related to smell and memory, compared to those that decline more slowly.

The changes were seen in parts of the brain involved in smell, including the amygdala and the entorhinal cortex.

Their risk was similar to that of those with the APOE-e4 gene, a known genetic risk factor for developing Alzheimer’s.

One in four people have the gene and are three times more likely to develop Alzheimer’s disease than those who do not.

The researchers hope to eventually use the examination to expand on the findings of volunteers, which is considered the gold standard for confirming whether a person has Alzheimer’s disease.

And they want to test using smell tests in clinics for seniors, like eye and hearing tests, to screen for and monitor early signs of dementia. A GOOD

They say smell tests are cheap, easy to use and involve sniffing a series of felt-tip sticks.

Each stick is filled with a different scent that people have to identify from a choice of four.

Ms Pacina said: “If we could identify people in their 40s, 50s and 60s earlier, we would have enough information to put them into clinical trials and develop better drugs.”

The team only identified participants who underwent fifth and MRI scans, which did just one thing — meaning they didn’t have the information to determine when structural brain damage began.

And the majority of volunteers were white, so more research is needed to see if other groups are similarly affected.

Loss or alteration of the sense of smell or taste was one of the three main symptoms of Covid, first identified by health officials when the virus swept the globe last year.

But as the virus mutated and new variants emerged, many infected people stopped reporting changes in their feelings.


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