Research suggests link between loss of smell from COVID and cognitive decline

If a COVID-19 infection took away your sense of smell, you're not alone.

Research shows more than 27 million people have experienced COVID-related smell or taste loss.

"We don't really understand why that happens," said Dr. Justin Turner, an associate professor of otolaryngology-head and neck surgery at Vanderbilt University Medical Center. "We believe it's due to some sort of inflammatory response of the smell nerve that occurs in these patients."

Now, new findings presented at the Alzheimer's Association international conference suggest there may be a link between loss of smell during COVID and cognitive decline.

Researchers followed 766 adults ages 55 to 95 after their COVID-19 infection. They found two-thirds of those infected had some type of cognitive impairment at the end of that year. In half of the participants, the impairment was severe.

In earlier findings, unrelated to COVID, researchers found that a decline in sense of smell can predict loss of cognitive function and be a warning sign of structural changes in areas of the brain important in Alzheimer's and dementia.

While more research is needed to confirm the relationship between loss of smell and brain health, doctors say the good news is most people with COVID do recover.

"It appears that the majority of patients get their smell function back within a couple of weeks," Turner said.

Turner says while there are no sure ways to bring smell back, systemic corticosteroids given early may help. Doctors are also using a method called olfactory retraining where patients smell different scents to retrain their nerves as a possible solution for smell recovery.