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NEW YORK: Until March, when everything started to taste like cardboard, Katherine Hansen had such a keen sense of smell that she could recreate almost any restaurant dish at home without the recipe, simply by remembering the aromas and flavors.
Then the coronavirus arrived. One of Hansen’s first symptoms was the loss of smell and then taste. Hansen still can’t taste food and says he can’t even tolerate chewing it. Now he lives mainly on soups and smoothies.
“I’m like someone who loses his eyesight as an adult,” said Hansen, a real estate agent who lives outside of Seattle. “They know what something should look like. I know what I should know, but I can’t get there. “
A diminished sense of smell, called anosmia, has emerged as one of the tell-tale symptoms of COVID-19, the disease caused by the coronavirus. It is the first symptom for some patients and sometimes the only one.
Often accompanied by an inability to taste, anosmia occurs abruptly and dramatically in these patients, almost as if a switch had been flipped.
Most regain their sense of smell and taste after recovery, usually within a few weeks. But in a minority of patients like Hansen, the loss persists and doctors cannot say when or if the senses will return.
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Scientists know little about how the virus causes persistent anosmia or how to cure it. But cases are mounting as COVID-19 spreads across the world, and some experts fear the pandemic could leave large numbers of people with a permanent loss of smell and taste.
The prospect has triggered an urgent fight among researchers to learn more about why patients are losing these essential senses and how to help them.
“A lot of people have been doing olfactory research for decades and it has received little attention,” said Dr. Dolores Malaspina, professor of psychiatry, neuroscience, genetics and genomics at the Icahn School of Medicine at Mount Sinai in New York. “COVID is turning that field upside down.”
SEPARATION AND ISOLATION
Smell is closely linked to both taste and appetite, and anosmia often deprives people of the pleasure of eating. But the sudden absence can also have a profound impact on mood and quality of life.
Studies have linked anosmia to social isolation and anhedonia, the inability to feel pleasure, as well as a strange sense of detachment and isolation.
Memories and emotions are intricately linked to smell, and the olfactory system plays an important, though largely unrecognized, role in emotional well-being, said Dr. Sandeep Robert Datta, associate professor of neurobiology in the School of Medicine of Harvard.
“You think of it as an additional aesthetic sense,” Dr. Datta said. But when someone is denied their sense of smell, it changes the way they perceive the environment and their place in the environment. People’s sense of well-being decreases. It can be really jarring and unnerving. “
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Many patients describe the loss as extremely upsetting, even debilitating, mostly because it is invisible to others.
“Smell is not something we pay much attention to until it disappears,” said Pamela Dalton, who studies the link of smell to cognition and emotion at the Monell Chemical Senses Center in Philadelphia. “Then people notice it and it’s quite distressing. Nothing is the same “.
WEAKEN LINKS
British scientists studied the experiences of 9,000 COVID-19 patients who joined a Facebook support group created by the charity group AbScent between March 24 and September 30.
Many members said that they had not only lost the pleasure of eating, but also of socializing. The loss had weakened their bonds with other people, affecting intimate relationships and leaving them feeling isolated, even cut off from reality.
“I feel alien to myself,” wrote one participant. “It is also a kind of loneliness in the world. As if a part of me is missing, since I can no longer smell or experience the emotions of basic daily life. “
Another said: “I feel puzzled, like I don’t exist. I can’t smell my home and I feel like home. I can’t smell fresh air or grass when I go outside. I can’t smell the rain. “
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Loss of smell is a risk factor for anxiety and depression, and the implications of generalized anosmia are of great concern to mental health experts. Dr. Malaspina and other researchers have found that olfactory dysfunction often precedes social deficits in schizophrenia and social isolation even in healthy individuals.
“From a public health perspective, this is really important,” Dr. Datta said. “If you think about the number of people with COVID worldwide, even if only 10 percent have a more prolonged loss of smell, we are talking about potentially millions of people.”
“THE COVID DIET”
The most immediate effects may be nutritional. People with anosmia can still experience basic tastes: salty, sour, sweet, sour, and umami. But the taste buds are relatively coarse preceptors. Smell adds complexity to taste perception through hundreds of odor receptors that send signals to the brain.
Many people who cannot smell will lose their appetite, putting them at risk for nutritional deficits and unintended weight loss. Kara VanGuilder, who lives in Brookline, Massachusetts, said she has lost 9 kg since March, when her sense of smell disappeared.
“I call it the COVID diet,” said VanGuilder, 26, who works in medical administration. “There’s no point indulging in brownies if I can’t really taste them.”
But while joking about it, he added that the loss has been heartbreaking: “For a few months, almost every day, I cried at the end of the day.”
PRIMARY ALARM SYSTEM
Odors also serve as a primary alarm system that alerts humans to hazards in our environment, such as fires or gas leaks. Decreased sense of smell in old age is one of the reasons that older people are more prone to accidents, such as fires caused by leaving burned food on the stove.
Michele Miller of Bayside, New York, was infected with the coronavirus in March and has not smelled anything since. Recently, her husband and daughter rushed her out of their home, saying the kitchen was filling with gas.
She had no idea. “It’s one thing not to smell and taste, but this is survival,” Miller said.
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Humans constantly scan their environments for odors that indicate potential change and damage, although the process is not always conscious, said Dr. Dalton of the Monell Chemical Senses Center.
Smell alerts the brain to the mundane, like dirty laundry, and the risky, like spoiled food. Without this form of detection, “people get anxious about things,” Dr. Dalton said.
DISTORTED PERCEPTIONS
Worse still, some COVID-19 survivors are plagued by phantom odors that are unpleasant and often noxious, such as the odors of burning plastic, ammonia or feces – a distortion called parosmia.
Eric Reynolds, a 51-year-old probation officer in Santa Maria, California, lost his sense of smell when he contracted COVID-19 in April. Now, he said, he often has bad odors that he knows don’t exist. Diet drinks taste like dirt; Soap and laundry detergent smell like standing water or ammonia.
“I can’t wash the dishes, I’m gagging,” Reynolds said. He is also haunted by the ghostly odors of corn chips and a scent he calls “the smell of old woman perfume.”
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It’s not unusual for patients like him to develop food aversions related to their distorted perceptions, said Dr. Evan R. Reiter, medical director of the Virginia Commonwealth University Taste and Smell Center, who has been tracking the recovery of about 2,000 COVID-19 patients who lost their sense of smell.
One of his patients is on the mend, but “now that he’s coming back, he says all or pretty much everything he eats will taste or smell like gasoline,” Dr. Reiter said.
Smell disturbance can be part of the recovery process, as receptors in the nose struggle to wake up again, sending signals to the brain that fail or are misread, Dr. Reiter said.
After loss of smell, “different populations or subtypes of receptors can be affected to different degrees, so the signals your brain is used to receiving when you eat steak will be distorted and can trick your brain into thinking you’re eating poop. dog or something else, that’s not nice. “
POSSIBLE TREATMENTS
Patients desperate for answers and treatment have tried therapies like smell training – sniffing essential oils or sachets with a variety of scents, such as lavender, eucalyptus, cinnamon, and chocolate, several times a day in an effort to regain their sense of smell.
A recent study of 153 patients in Germany found that training could be moderately helpful in those with lower olfactory function and in those with parosmia.
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Dr. Alfred Iloreta, an otolaryngologist at Mount Sinai Hospital in New York, has started a clinical trial to see if taking fish oil helps restore the sense of smell. The omega-3 fatty acids found in fish oil can protect nerve cells from further damage or help regenerate nerve growth, he suggested.
“If it doesn’t smell or taste, you have a hard time eating anything, and that’s a huge quality of life problem,” Dr. Iloreta said. “My patients and the people I know who have lost their scent are completely devastated.”
Reynolds feels the loss most acutely when he walks to the beach near his home. It no longer smells the ocean or the salty air.
“My mind knows what it smells like,” he said. “And when I get there, it’s not there.”
By Roni Caryn Rabin © The New York Times
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