Numerous studies have shown that neurological fallout from COVID-19 can linger long after the initial infection has cleared. Some neurological and psychiatric symptoms, like brain fog and dementia, can persist for as long as two years. Why this occurs isn’t yet known.

Some experts believe immune system cells in the brain and spinal cord, called microglia, are to blame for Long COVID neurological impacts. They believe these cells become activated by the SARS-CoV-2 virus and cause inflammation that leads to a disruptive environment for brain health. Other experts believe Long COVID brain effects stem from autoimmune issues.

What the researchers did

A research team based at São Paulo, University of Campinas sought to better understand how COVID-19 impacts the brain.

• 254 people (177 women, median age 41) with mild COVID-19 were evaluated for depression and anxiety about three months after COVID testing.
• Participants were divided into two groups:
  • Asymptomatic (152 people)
  • Symptomatic, with anxiety and depression (102 people)

Brain structure and function were assessed via MRI scanning.

• Grey matter was examined in the two groups versus 148 healthy controls.
• Resting-state connectivity of a dozen large brain networks was examined in 84 asymptomatic and 70 symptomatic participants versus 90 controls.

What they found

Regarding differences in brain structure:

• The symptomatic group showed decreased grey matter in two regions, whereas no change was observed in the asymptomatic group.

Concerning differences in brain function:

• The symptomatic group showed a pattern of hyperconnectivity—a common response to disruption of neural networks—on both sides of the brain in all 12 networks, whereas just five networks showed hyperconnectivity in the asymptomatic group.

What it means

The study adds to growing evidence that the makeup and function of the brain are impacted by the SARS-CoV-2 virus. Compared to asymptomatic people, those with Long COVID anxiety and depression showed brain changes suggestive of cognitive dysfunction. 

Said Clarissa Yasuda, M.D., Ph.D., of her team’s findings, “Our results suggest a severe pattern of changes in how the brain communicates as well as its structure, mainly in people with anxiety and depression with long COVID syndrome, which affects so many people. Our findings are concerning, as even people with a mild case of COVID-19 are showing changes in their brains months later.”

“This abstract, along with all the other evidence,” added Ziyad Al-Aly, M.D., who heads research and development at the Veterans Affairs St. Louis Healthcare System and wasn’t involved with the study, “is a compelling reason to double our effort to further understand Long COVID and its various sequelae or consequences.”

*George, J. (2023, February 20). Brain Structure, Widespread Connectivity Changes Seen With Long COVID. MedPage Today. https://www.medpagetoday.com/meetingcoverage/aan/103186