Can COVID-19 Cause Brain Fog?

5 min read  |  November 17, 2020  | 

As if lingering physical effects from COVID-19 were not worrisome enough, elderly adults who have survived are reporting issues with “brain fog.”

Though not a medical term, neurologists say it accurately labels the confusion and lack of concentration experienced by patients after a severe bout with the virus.

“It’s a lay term to capture and describe the lack of mental clarity, problems with focusing, even problems with memory,” says James E. Galvin, M.D., M.P.H., director of the Comprehensive Center for Brain Health. “That’s what people report, like trying to get around in a fog.”

There are yet no numbers about how many or what percentage of coronavirus cases result in brain fog.

One French survey of 120 patients revealed 34% had memory loss, and 27% had concentration problems months later. Another survey, this one of almost 4,000 members of Survivor Corps, a group of people who have connected to discuss post-COVID life, showed that more than half had problems concentrating or focusing. (This turned out to be the fourth most common symptom out of the 101 long-term and short-term conditions reported.) At least a third also reported memory problems, dizziness, or confusion.

Dr. Galvin has not seen post-COVID 19 patients in his practice but has heard and read about the phenomena. “Anecdotally, it seems to be happening across the board but mostly in the more serious cases and more among older patients.”

Overall viral recuperation in seniors tends to be hampered by existing medical ailments and age-related weakness.

Cognitive recovery has proven to be no exception.

Published reports tell of patients who have forgotten events in their immediate past, gotten lost in familiar neighborhoods, or have been unable to perform daily tasks they once were able to do without assistance.

In general, the elderly are at a higher risk of contracting COVID-19 and suffering more severe symptoms once they have it. According to the Centers for Disease Control and Prevention, eight out of 10 coronavirus deaths reported in the U.S. have been patients 65 and older.

However, most seniors will survive COVID-19. Even for the most at-risk age group — people 85 and older — more than 70% of confirmed cases recover. Unfortunately, this demographic is the most likely to have a drawn-out convalescence. In addition to confusion and forgetfulness, their post-COVID-19 months may be marked by continuing issues with breathing, stamina, and muscle weakness.

Some of this is to be expected.

“Older people have many more co-morbidities which can make any illness a lot worse,” Dr. Galvin explains. For instance, an elderly patient may already have the beginning of undiagnosed dementia, which may be exacerbated by time in the hospital. Older patients also tend to have more heart disease and diabetes, all of which can contribute to cognitive impairment.

“Even if you were healthy before, this can act as an unmasking of a sort,” Dr. Galvin says. “We know that dementia can be developing long before the symptoms are noted.”

ICU physicians also have reported more cases of delirium – a state of severe confusion – among their senior COVID patients, a rate of up to 70 or 80%. ICU delirium is actually common in other diseases, too, with about 2 out of 3 ICU patients experiencing the condition. It’s likely caused by less oxygen to the brain, medications such as sedatives or narcotics, isolation from family and friends, even chemical changes in the brain itself.

Among the elderly, an incidence of delirium in the hospital can have devastating long-term effects, with acute confusion, agitation, or lethargy persisting for weeks, even months. Delirium has also been associated with an increased risk of losing independence.

Physicians are not yet sure what may cause this cognitive impairment in older COVID-19 survivors, but there are theories.

“This could be a consequence of the virus itself,” Dr. Galvin says, “of our body fighting off the virus.”

When our immune system goes into battle, it releases cytokines, small proteins that coordinate the body’s response to the interloper. Cytokine storms, or the body going into attack overdrive, has been long considered the cause of many coronavirus-related deaths. Can it also be blamed for the brain fog?

Or is it the blood clots caused by the virus? Or inflammation in blood vessels leading to the brain? Or perhaps the medications themselves? “Right now, we’re working in the dark,” Dr. Galvin adds. “We just don’t know. We’ve not experienced COVID-19 before and can only look at what’s happened with other viruses.”

This doesn’t mean we’re helpless. People can still fend off the virus by following CDC guidelines of mask-wearing and physically distancing, he says. He also recommends developing good brain habits: exercising, keeping mentally active, and staying socially engaged.

“We have the power to do everything to preserve our cognitive abilities as much as we can, brain fog or not.”

Ana Veciana-Suarez, Guest Columnist

Ana Veciana author

Ana is a regular contributor to the University of Miami Health System. She is a renowned journalist and author who has worked at The Miami Herald, The Miami News, and The Palm Beach Post. Visit her website at or follow @AnaVeciana on Twitter.

Tags: covid-19 in Miami, Dr. James Galvin, neurology

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