A new study in the UK has revealed that the Covid-19 virus can cause the brain to shrink, albeit partially.
Comparing brain MRIs (magnetic resonance imaging) taken before and after Covid, scientists observed that the brain shrank by 0.2 percent to 2 percent in total.
Even in mild cases, gray matter decreased in parts of the brain related to smell and memory.
Gray matter is also a key structure for functions such as memory and decision making.
The research of Oxford, one of the leading universities in England, was published in the scientific journal Nature.
The researchers analyzed the scan images of 500 thousand people whose health was followed by the UK Biobank project, which carries out genetic studies in the UK, in the last 15 years.
Thus, they could take into account the scans taken before the Covid pandemic, as well as taking into account how the virus affects health in the long term.
Brain may struggle with complex mental functions
For research;
- With brain scans of 401 participants, 96 percent of whom had mild Covid-19, an average of 4.5 months after contracting the disease,
- Scans of 384 participants who have never been diagnosed with Covid were examined
According to the research;
- In those who contract the virus, the overall size of the brain shrinks by 0.2 percent to 2 percent.
- There was a decrease in gray matter in parts of the brain related to smell and memory.
- It has been noted that in those who survived Covid, the mind had difficulty in performing complex tasks.
Brain can ‘heal itself’
Researchers do not have data on whether these changes in the brain are permanent.
On the other hand, they are of the opinion that the brain has the potential to heal.
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The lead author of the research report is Prof. “For research, we focused largely on mild infections, and it was surprising to see how much their brains had changed compared to those who were not infected,” said Gwenaelle Douaud.
Pointing out that the brain has a flexible structure, that is, it can heal itself, Prof. “There’s a good chance that the harmful effects of the infection will diminish over time,” Douaud added.
The reduction in gray matter was most evident in the part of the brain where the olfactory function takes place.
It has not been proven that the virus directly targets this region.
Cell death may also occur as a result of less use of this part by those who experience loss of smell due to Covid.
The MRI images taken for the research were taken during the period when the original Covid virus and the Alpha variant of the virus were dominant, and loss of smell and taste were the main symptoms.
In the new variant of the virus, Omicron, there is a notable decrease in these symptoms.
Professor of Neurology at University College London. Werring notes that other health factors may play a role in these changes in the brain.
“It is not clear how mild changes in cognitive functions affect the daily functions of the brain,” said Werring, emphasizing that these changes are not seen in every person infected with the virus.