Can COVID-19 Cause Brain Fog?

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We’ve all heard about the common symptoms of COVID-19, including cough, shortness of breath, headache, fatigue and fever. But after the COVID-19 symptoms go away, research shows that 20-30 percent of people may experience brain fog — a lingering problem that can affect the ability to perform everyday tasks.

What is brain fog?

Brain fog refers to problems with thinking, memory and concentration, but for many patients, it can be challenging to describe.

“Patients often say they just don’t feel right,” says Talya Fleming, M.D., medical director, Post-COVID Rehabilitation Program at JFK Johnson Rehabilitation Institute. “We use the term ‘fog’ because patients feel that something is over them that is making things not as crisp or distinct as they were before.”

“I have heard patients say they have trouble with memory, are easily distracted, have trouble following a conversation, and have difficulty concentrating and attending to everyday tasks,” explains Kristie R. Soriano, MS, CCC/SLP, manager of Outpatient Speech Programs at JFK Johnson Rehabilitation Institute.

Symptoms of brain fog may also appear as:

• Walking into a room and forgetting why you are there
• Losing your train of thought
• Difficulty thinking of the right words
• Difficulty remembering what you just read
• Taking longer to complete tasks
• Forgetting recipes or steps when cooking
• Leaving lights or appliances on unintentionally
• Forgetting what you were doing after becoming distracted

“These symptoms often emerge after patients get through the medical emergency and go back to work,” comments Soriano. “In many cases, patients are having trouble functioning on the job or managing day-to-day responsibilities, which can negatively impact their quality of life.”

What causes brain fog after COVID-19?

According to Dr. Fleming, the medical community is still researching potential causes of brain fog after COVID-19. Researchers have identified several possible causes, including:

• Lack of oxygen caused by lung damage
• Inflammation affecting brain cells
• An autoimmune disorder that is causing the immune system to attack healthy cells in the body
• Lack of blood flow caused by swelling of the small blood vessels in the brain
• Invasion of infectious cells into the brain

“We know that different people have a wide range of long-term complications after COVID-19 infection, and a combination of factors may cause brain fog,” says Dr. Fleming.

How long does post-COVID brain fog last?

For some patients, post-COVID brain fog goes away in about three months. But for others, it can last much longer.

“We are seeing patients who were diagnosed with COVID-19 in March 2020 that are still experiencing brain fog,” shares Soriano. “Although these patients report improvement in their symptoms, they still aren’t back to baseline.”

Patients who experience brain fog after COVID-19 should also be prepared for a “waxing and waning” course of recovery.

“Some days, patients may feel great — but two or three days later, they may not feel so great,” notes Soriano. “It’s important for patients not to get discouraged because recovery isn’t a straight course, and building up cognition can take time.”

Is help available for post-COVID brain fog?

A treatment plan for post-COVID brain fog may employ various strategies to help patients manage day-to-day life, including:

• Using a calendar, note-taking, or “to-do” lists to assist with memory
• Using word associations to help with finding the right words
• Minimizing distractions to improve attention
• Building up cognitive endurance to reduce cognitive fatigue and improve concentration

“Over time, as the patient recovers, they will need to rely on these strategies less and less,” says Soriano.

Dr. Fleming also says that the damage to the brain caused by COVID is more diffuse than with stroke or other types of brain injury, so it requires specialized treatment.

For example, increasing physical activity can have many beneficial effects, such as oxygenating and clearing toxins from the body. However, after COVID-19, some patients can experience a condition called post-exertional malaise, which results in a huge drop in energy levels after activity.

“We are all learning more about the long-term effects of COVID-19 as time passes. Oftentimes, patients who come to see us have already been to a primary care physician and other specialists who didn’t know how to help,” says Dr. Fleming. “We validate their concerns and develop a customized treatment program using strategies that we know work with other patients recovering from brain injury.”

“If you or a loved one is experiencing brain fog after COVID, or even if you aren’t sure, don’t just sit and wait for things to improve — get checked out,” said Soriano.

Next Steps & Resources

• If you're experiencing brain fog due to long COVID, get help at the Hackensack Meridian Health COVID Recovery Center.

The material provided through HealthU is intended to be used as general information only and should not replace the advice of your physician. Always consult your physician for individual care.