Scientists research reasons for brain fog caused by COVID-19

by Sudeepthi Ravipati (’24) | March 21, 2022

Art by Nicole Schubert (’22)

When COVID-19 took the world by storm, the virus significantly changed the world of medicine. While treatable for many, its impacts are extremely dangerous for others. According to a Fair Health report, an estimated 25 percent of COVID-19 patients develop long-term symptoms. Some of the most commonly experienced symptoms are a loss of taste and smell. However, one of the most puzzling effects is long-term brain damage.

The term “brain fog” has often been used to characterize the symptoms people with this damage are facing. “They manifest as problems remembering recent events, coming up with names or words, staying focused, and issues with holding onto and manipulating information, as well as slowed processing speed,” says senior study author Joanna Hellmuth, MD, MHS, of the UCSF Memory and Aging Center.

A study published in March 2022 suggests that even those who experience mild symptoms of COVID-19 can suffer brain damage. Researchers in this study examined brain scans of 785 participants in the UK Biobank research project. Approximately four hundred people from the group caught the virus, and their brain scans were then compared to the scans of participants who did not contract the virus. 

Researchers found that people who were infected appeared to have less gray matter in their brain, particularly in the areas responsible for cognitive processes and memory. The shocking part is that the scale of this damage equates to around one year of normal aging, according to Gwenaëlle Douaud, the lead author of the study.

A team from the University of California, San Francisco found that those who experienced cognitive decline after COVID-19 also showed signs of damage in their cerebrospinal fluid, a liquid that surrounds the brain and spinal cord. 

Both of these studies suggest that brain fog is potentially associated with microscopic inflammatory processes happening within the brain. “With COVID-19, there’s an activation of the immune system that persists for months, which can affect neural connections in the brain,” says Dr. Zabner, an infectious disease specialist and co-director of Cedars-Sinai’s COVID-19 Recovery Program. “The stress of navigating COVID-19—constantly being in ‘fight mode’—can affect brain function, too.”

Additionally, people experiencing brain fog commonly had pre-existing conditions that could have contributed to their neurological symptoms. Research performed by the UK Biobank corroborated that the neurological impacts could have been associated with pre-existing brain vulnerability. In the UCSF study, patients with brain fog also had 2.5 cognitive risk factors, including conditions like diabetes and irregular blood pressure.

Many people have adjusted to a “new normal” because of COVID-19. However, for others, life has been severely altered. The progress scientists have made researching brain fog is notable, but the process of finding solutions or therapy for patients is ongoing. Brain fog is a frustrating symptom for many people with COVID-19, but scientists are optimistic that they can uncover more about its causes in the near future.

Categories: Science

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