How a sudden loss of smell can be a sign of DEMENTATION –

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

Studies have previously linked a gradual loss of smell to a disorder of amnesia.

But new research suggests that rapid degradation may be a better indicator.

US researchers followed more than 500 seniors in the United States for nearly 20 years.

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

The study’s senior author, Professor Jayant Pinto of the University of Chicago, said it provides “another clue” to the link between smell and dementia.

He suggested performing common smell tests as hearing and vision checks for older people to screen for the disease.

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

Memory plays a vital role in the ability to recognize odors, and researchers have long known that there is a link between the senses and cognitive decline.

Research has shown that amyloid protein “tangles” in the brain – a clear sign of dementia – often first appear in areas of the brain involved in olfaction and memory.

However, it is not yet known whether this damage actually causes the person to lose their sense of smell.

Professor Pinto and his team wanted to investigate whether this change was associated with a person’s loss of smell and brain function over time.

Lead author Rachel Pacyna, a researcher at the university, said: “Our idea was that people with a rapidly declining sense of smell would be in a worse condition over time and more likely to develop brain problems and even Alzheimer’s — who gradually reduce or maintain a normal sense of smell. compared to humans.

Researchers followed 515 people in their seventies who did not initially have dementia or cognitive problems for 20 years.

All of the volunteers lived in nursing homes and were tested annually for their ability to recognize specific dementia odors and signs. Some have even undergone MRI scans.

The decline in their sense of smell was measured by scent test scores that were then plotted. The downtrend of the slope is labeled as “severe”, “reduced”, “unchanged” or “improved”.

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

Those who did not have classic Alzheimer’s symptoms but experienced a rapid decline in their sense of smell were 89% more likely to develop memory deprivation disorders than those who lost their sense of smell.

Strong olfactory loss was also associated with a higher risk of having less gray matter volume in regions of the brain associated with smell and memory, compared to those with slower decline.

The changes were most pronounced in parts of the brain used for smell, including the amygdala and entorhinal cortex.

Their risk was comparable to those with the APOE-e4 gene, a known genetic risk factor for the development of Alzheimer’s disease.

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

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

They want to test with smell tests in high-end clinics in the same way as eye and hearing tests to detect and detect early signs of dementia. GOOD

They said the scent tests were inexpensive and easy to use, and they picked up a series of stick scents that looked like markers.

Each stick is infused with a different scent that individuals must identify from among four options.

“If we can detect early on people in their 40s, 50s and 60s at highest risk, we could potentially have enough information to enroll them in clinical trials and develop better drugs,” said Ms. Pacyna.

The team noted that only a fifth of the participants had undergone an MRI scan, and those who had only one meant they had no data to determine when structural brain changes began.

And most of the volunteers were white, so more research is needed to find out if other groups were similarly affected.

Loss or change in smell or taste was one of the top three symptoms of Covid, first identified by health leaders when the virus swept the world last year.

But now that the virus has mutated and new variants have emerged, many infected people no longer report changes in their senses.