Training the brain to smell again

About one in eight Americans over the age of 40 has smell dysfunction.

It can happen at any age from things like injuries or even as a result of a virus like the common cold.

There are no treatment options to restore sense of smell, but some doctors think they can re-train the brain to recover at least some, if not all, of what's lost.

Patrick Leahy has a new appreciation for stopping to smell the flowers.

"Once you lose anything, then you realize, you know, what you've lost," Patrick says.

After a simple viral infection, Patrick lost his sense of smell. Luckily, he found Dr. Jay Piccirillo.

"We think a lot of people have this condition, but they don't seek medical care," Piccirillo explains.

People can lose their sense of smell after an injury or with aging, but for some, it results from a viral infection like the common cold.

"We think the nerve of smell that enters from the brain into the nose has in one way or another been injured by the virus," Piccirillo says.

In an attempt to re-train the brain to smell again, Piccirillo gave patients four essential oils to smell twice a day for 12 weeks.

"Through brain training, through smelling these smells, we're trying to, again, get the brain neurons to come back and to allow them to smell," Piccirillo explains.

To track progress, patients were asked to identify a variety of odors using simple sniff tests.

"Potentially a big payoff for little investment in time and effort, you bet, and doesn't cost a whole lot either," Piccirillo says.

Patrick's sense of smell improved from 30% to 70%.

"They've both come back dramatically, smell and taste," he says.

Patrick is still smelling the oils every day even though the study is over. Piccirillo says patients can easily do this at home.

If you think you have trouble smelling, he says there's no harm in trying it yourself.

The oils used in the study were rose, lemon, eucalyptus and clove, but you can tailor it to what works for you.



REPORT: MB #4584

BACKGROUND: One to two percent of North Americans report problems with their sense of smell. Problems with the sense of smell increase as people get older and they are more common in men than women. In one study, nearly 25 percent of men ages 60–69 had a smell disorder, while about 11 percent of women in that age range reported a problem. Smell disorders have many causes, with some more obvious than others. Most people who develop a smell disorder have experienced a recent illness or injury. Common causes of smell disorders are aging, sinus and other upper respiratory infections, smoking, growths in the nasal cavities, head injury, hormonal disturbances, dental problems, exposure to certain chemicals, such as insecticides and solvents, numerous medications, including some common antibiotics and antihistamines, radiation for treatment of head and neck cancers, and conditions that affect the nervous system, such as Parkinson's disease or Alzheimer's disease. (Source:

TREATMENT: In cases where the loss of smell results from sinus disease, oral and topical steroids often provide relief. Sometimes surgery is required to reduce the obstruction of odors to the sensory nerve cells. Sinus disease usually requires long-term management, and fluctuations in the ability to smell are common. In contrast to chronic sinus inflammation, success in treating people with loss of smell resulting from head injury, upper respiratory infection, or aging is poor. The natural ability of the olfactory system to repair itself allows for some patients to regain the sense of smell after a respiratory infection-related loss or head injury. This recovery can take over a year and can be so gradual that people have difficulty recognizing the change. (Source:

NEW RESEARCH: Jay Piccirillo, MD, an Otolaryngologist from Washington University of St. Louis is studying smell training. He explained, "We're looking at whether or not something called olfactory training, which is smelling certain odors, essential oils, on a regular daily basis can help retrain the brain to learn about those smells again. People who have lost their sense of smell following a cold or a virus are enrolled in the trial and asked to smell four different essential oils every day. We're looking to see if the brain can retrain itself."

(Source: Jay Piccirillo, MD)