Researchers identify COVID-19-associated brain damage months after infection

Contracting the COVID-19 virus may result in damage to brain tissue and cognitive decline, according to new study released on Monday.

Researchers from the University of Oxford looked into brain changes in 785 participants, who each received two brain scans, in the long-term UK Biobank study. Among the participants, 401 contracted the coronavirus between the two scans, giving researchers an opportunity to see changes between the first and second scans.

Researchers observed a reduction in grey matter thickness in both the orbitofrontal cortex, the part of the brain believed to be associated with decisionmaking, as well as the parahippocampal gyrus, which plays a part in the brain’s emotional and behavioral responses.

The participants in this study were aged between 51 and 81.

Greater markers of tissue damage were also observed in the primary olfactory cortex, which is a part of the brain that receives information from smells. A common symptom of COVID-19 is a loss of taste or smell that can last long after a person has recovered from their infection.

The participants who contracted the virus were observed to have experienced a larger reduction in global brain size and were also found to have a greater average cognitive decline. Participants who tested positive for COVID-19 were found to take longer to complete a cognitive test, indicating a worsening of executive function.

“It is brain damage, but it is possible that it is reversible,” Gwenaëlle Douaud, lead author of the study and an associate professor at the Nuffield Department of Clinical Neurosciences at Oxford, told NBC News. “But it is still relatively scary because it was in mildly infected people.”

The study also noted that these results were representative of an average and that not all patients who contract COVID-19 will display brain abnormalities. The study also had some limitations, including the lack of information on how severe the individual cases of COVID-19 were, though researchers accounted for which cases resulted in hospitalization.

There were also few nonwhite participants in the study, according to researchers, and they were unable to identify specific strains of COVID-19 among the participants.

“Whether these abnormal changes are the hallmark of the spread of the pathogenic effects, or of the virus itself in the brain, and whether these may prefigure a future vulnerability of the limbic system in particular, including memory, for these participants, remains to be investigated,” read the study.