Brain shrinkage: Even mild cases of corona can leave a mark on the brain, such as a decrease in gray matter

In a new study of brain imaging of the same people before and after a corona illness, it was found that participants who had even a mild corona showed an average decrease in the size of the entire brain.

By: Sarah Hallwell, Research Fellow, Faculty of Health Sciences, Curtin University and Perron Institute for Neurological and Translational Sciences, Curtin University, UK

Researchers are constantly gaining important insights into the effects of the corona virus on the body and brain. Two years after the start of the pandemic, these findings raise concerns about the long-term effects the coronavirus could have on biological processes such as aging.

As a cognitive neuroscientist, I have focused my research in the past on understanding how normal brain changes associated with aging affect people's ability to think and move—especially in middle age and beyond.

But when evidence arrived showing that the corona virus can affect the body and brain for months after infection, my research team shifted some of its focus to better understand how the disease might affect the natural process of aging. The motive was largely new and convincing research from the UK on the effects of the corona virus on the human brain.

In a large study published in the journal Nature on March 7, 2022, a team of UK researchers studied brain changes in people aged 51 to 81 who experienced corona. This research provides important new insights into the effect of the corona virus on the human brain.

For the study, the researchers relied on a database called UK Biobank, which contains brain imaging data from more than 45,000 people in the UK since 2014. This means there was baseline data and brain imaging for all of these people from before the pandemic.

The research team compared people who had experienced corona with participants who had not, and rigorously matched the groups by age, gender, the date of the baseline examination and the location of the study, as well as common disease risk factors, such as health variables and socioeconomic status.

The team found significant differences in the gray matter - or the nerve cells that process information in the brain - between those who were infected with Corona and those who were not. Specifically, the thickness of gray matter tissue in areas of the brain called the frontal lobe and the temporal lobe was reduced in the corona group, unlike the typical patterns seen in people who were not infected with corona.

In the general population, it is normal for there to be some change in the volume or thickness of the gray matter over time as people age. But the changes were more extensive than usual in people infected with Corona.

It is interesting to note that when the researchers separated the people whose illness was severe and required hospitalization, the results were the same as for those who experienced a milder corona. That is, people infected with corona showed a loss of brain volume even when the severity of the disease did not require hospitalization.

The researchers also examined changes in the performance of cognitive tasks and found that those infected with Corona were slower in processing information than those who were not infected. There was a correlation between this processing ability and the volume in an area of ​​the brain called the cerebellum, which indicated a connection between the volume of brain tissue and cognitive performance in those who were sick with Corona.

This research yielded particularly great value and important insights because of the large size of the samples before and after the disease in the same people, and also because of the strict matching between the people who got and didn't get corona.

For the article in THE CONVERSATION

More of the topic in Hayadan:

• Researchers from Tel Aviv University have developed a serological test to detect corona antibodies and will use it to test IDF soldiers
• The closure caused a structural change in the areas of stress and anxiety in the brain
• A huge international study strengthens the connection between corona and stroke in young people who have fallen ill
• Long, Long Covid: the lack of sense of taste and smell continues in many cases long after recovery from Corona