Wash U researchers hope to train the brain how to smell again
Two years ago, Joe Weissmann lost something many take for granted: his sense of smell.
“I still eat, but I don’t enjoy it near as much, because I can’t taste any food or have any sensation of smell,” said Weissmann, a lifelong St. Louis resident and retired sheet metal worker.
Still, Weissmann hasn’t lost hope. He is now a participant in a Washington University research study designed to understand how the brain changes after a person loses their sense of smell. The goal is to eventually develop a treatment for long-term smell loss.
“Loss of sense of smell and taste is not just a quality-of-life problem,” said Jay Piccirillo, professor of otolaryngology at Washington University School of Medicine and head of the study. “More importantly, it takes away some of that protective effect that smell gives us when there’s gases in the air or dangerous products in the air.”
A recent study reports up to 20 percent of the U.S. population may suffer from decreased sense of smell, but estimates may be inaccurate because so few people seek medical attention. Though viral infection is thought to be one of the most common causes of smell loss, trauma to the nose, neurodegenerative diseases and tumors can also trigger it.
Weissmann lost his sense of smell and taste after having a series of head colds and sinus infections. He went to several specialists, including an allergist and an otolaryngologist, but his sense of smell never returned.
“When you have something for 57 years and then you lose it, it’s a little discouraging,” Weissmann said.
As part of the study, Weissmann and 16 other participants were given a nasal saline rinse for 30 days to reduce inflammation. Researchers then retested each participant to see if their sense of smell had improved.
During his reassessment testing, Weissmann sat blindfolded in a chair while a medical resident presented him with odor-treated pens called Sniffin’ Sticks.
“I tell my brain, 'Now, smell, smell. You gotta pick this out,'” he said, after taking a long sniff and hesitantly identifying the odor as leather.
Participants whose sense of smell does not improve will take part in “smell training,” in which they sniff four concentrated essential oils, including eucalyptus and rose, twice a day for three months. Weissmann is in that group.
Before and after the smell training, researchers at WashU will scan patients’ brains using magnetic resonance imaging (MRI).
“The main question we really want to answer is, 'Can we help them to smell better by getting the brain to learn to smell these essential oils?'” Piccirillo said. “Can we get the brain to set up new pathways, new connectivity to improve patients’ ability to smell?”
The concept of smell training has its roots in neuroplasticity — the ability of the brain to change and develop new connections. Although scientists have long known that the brain changes as we learn, Piccirillo said doctors have only begun to study the practical applications of neuroplasticity in the last 10 to 20 years.
For his part, Weissmann hopes that someday he’ll be able to enjoy the smell and taste of his favorite foods again.
“Anything that would help me get my sense of smell and taste back would be a miracle to me,” Weissmann said. “I didn’t realize just how extremely important and beautiful it was to have it.”
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