Study finds that Covid-19 can make the brain “shrink”

UK scientists have noticed that Covid-19 can shrink the brains of infected patients. The reduction mainly affects the regions involved in odor processing and the memory of individuals. It is not yet known whether this complication can be partially or completely reversed in the future.

Published in a scientific journal nature, the manuscript – the original text of a study that has not been reviewed by other scholars – was developed by researchers at the University of Oxford, UK. According to the authors, changes in brain structure can affect people who have experienced milder or more severe cases of COVID-19.

“Although the injury is mild at 96%, [a maioria] of the participants [do estudo]We observed the greatest loss of gray matter volume and the greatest tissue damage in affected participants, on average, 4.5 months after injury,” explains Gwenell Dowd, an Oxford professor and one of the study authors, in a statement.

Additionally, Daoud commented that the study also determined that patients had a decline in mental abilities to perform complex tasks. “This mental decline was partly related to these brain disorders. All of these negative effects were more pronounced at older ages,” the neuroscientist adds.

Understanding the study

In the British study, the team of researchers analyzed the data of 785 volunteers, aged between 51 and 81, regardless of whether or not they had contracted Covid-19. However, all participants had previously had some brain imaging tests – more precisely, magnetic resonance imaging (MRI) of the brain – and test results were available from the UK Biobank.

Of the total registered in the survey, 401 individuals contracted the coronavirus sometime between March 2020 and April 2021. In addition, 15 of those infected (4%) were hospitalized as a result of the infection. A further 384 participants did not receive a COVID-19 diagnosis during the study period.

At the end of the follow-up study, all volunteers underwent a second brain scan, in which the team of scientists was able to determine whether changes had occurred in the brains of the affected subjects and the control group, compared to the result of a scan that had been performed, on average, three years earlier.

In the analysis phase, participants were matched by age, gender, and risk factors for COVID-19 infection – such as smoking or diabetes.

Reducing the size of the brain after infection with the Covid virus

When the researchers compared the changes in the brain between the control group and those of infected patients, it was possible to notice a decrease in volume in different parts of the central nervous system organ, especially in the cerebral cortex (the gray area) of those who were touched by the virus.

In addition, people who contracted Covid-19 had a greater decrease in total brain volume than the control group. Tissue damage associated with the primary olfactory cortex could also be observed. This is the structure that receives sensory information from the smell-detecting neurons in the nose.

On average, the affected group had a 0.2% to 2% greater loss than the control group over the study period. To illustrate this decrease, people over the age of 60 lose about 0.2% to 0.3% of gray matter in areas related to memory each year. This way the changes are more important than, say, the aging process.

Now, the team needs to understand the implications of the discovery on the health of individuals, which still cannot be assumed. “Whether these effects will persist in the long term remains to be investigated in further follow-up,” the study authors explain.

source: natureAnd the Oxford university And the Live Science