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While the world is learning to live with COVID-19, scientists still have many unanswered questions about how the infection affects the body and brain—not just when people are sick, but over the long term as well.
In a study presented at the annual meeting of the Radiological Society of North America, researchers report on changes to the brain among people who have recovered from COVID-19.
The scientists conducted MRI scans of the brains of 46 people who had had COVID-19 within the past six meses, and compared them to the scans of 30 people who had never been infected. They found that most of the people who had recovered from COVID-19 had changes in the circulation of tiny blood vessels in the frontal lobe and brain stem areas, which are involved in higher order cognitive skills such as language expression and voluntary movements. Compared to the control group, this group showed reduced circulation in these microvessels. Exactly how that might translate to daily activities isn’t clear yet; the researchers did not follow up with detailed analyses of cognitive function in the two groups. But Bharat Biswal, professor of biomedical engineering at New Jersey Institute of Technology and a co-investigator of the research, says the team is exploring how these changes might affect other functions. Some of the participants, for example, had high blood pressure or other chronic conditions that might also play a role in how their brains were affected by COVID-19, and the scientists are looking into whether the people with such underlying health conditions showed different levels of brain changes compared to those without these conditions.
The study builds on previous work Biswal and his colleagues conducted, which documented structural changes in the brain that distinguished people who had been hospitalized and recovered from COVID-19 from those who had not been infected. That study found changes in the limbic system and hippocampus of the brain, which oversees emotional and behavioral activities, as well as memory.
Taken together, says Biswal, the results “provide an initial idea of where to look and what parameters to look at” for scientists studying the effects of Long COVID. He and his team are hoping to track the volunteers in the study for longer to better document how lasting the changes are.
“COVID-19 has multi-dimensional effects on the body,” he says, including in the brain. And while the scientists haven’t yet investigated people who have been reinfected, multiple bouts with COVID-19 may also cause cumulative changes on various systems in the body. Biswal says he “worries a little bit” about how reinfections “might show up in the brain and other organs. There are still more studies to be done to understand how COVID-19 affects the brain and body.”