Even a mild course of Covid-19 can trigger abnormalities in the brain and shrink the entire organ. Researchers from the University of Oxford found this out.
A corona infection can apparently damage the human brain even in mild cases. This is the conclusion of researchers at Oxford University in a study published in the journal Nature. The researchers used brain scans and cognitive tests to study the brain changes in people infected with Sars-CoV-2.
After a corona infection, the thickness of the gray matter in brain regions that control memories and emotions, among other things, decreased. Parts of the central nervous system are called gray matter. The researchers also documented damage in brain areas linked to the sense of smell.
In addition, the entire organ shrank more in infected subjects than in non-infected subjects. It’s normal for people to lose a small amount of gray matter in memory-related areas of the brain each year as they age – 0.2 to 0.3 percent, according to study lead author Gwenaëlle Douaud, associate professor of neuroscience at Oxford University. told CNN. In those infected, the researchers found that the brain size had shrunk by an additional 0.2 to two percent compared to the control group. In addition, a stronger cognitive decline was observed in the infected subjects. Those suffering from Sars-CoV-2 suffered, among other things, from impaired concentration and attention. The worst performers in this study were those who had lost the most brain tissue.
The basis were 785 brain scans
The study was based on the brain changes measured in 785 participants between the ages of 51 and 81 using two brain scans. The data of these patients comes from the “UK Biobank”, a medical database. Including 401 cases that tested positive for Sars-CoV-2 between the first and second scan. The control group consisted of 384 people and none had contracted the coronavirus.
There was an average of four and a half months between the diagnosis of the Covid 19 infection and the second scan. Because images of the brains before the infection were also available, it is unlikely that risk factors that existed before the infection were misinterpreted as the effects of Covid-19, the study says. The researchers also point out that the above-mentioned abnormalities in the brains were also observed when the 15 people with severe courses who were treated in the hospital were excluded from the study.
It is unclear whether changes in the brain are permanent
With this study, the scientists were not yet able to clarify why exactly these changes occurred in the brain of those infected with Covid-19. “Because the abnormal changes we’re seeing in the brains of infected participants may be related in part to the loss of their sense of smell, it’s possible that recovery will result in these brain abnormalities becoming less pronounced over time. Likewise, it’s likely that the harmful effects of the virus decrease over time after infection. The best way to find out would be to rescan these participants in a year or two,” Gwenaëlle Douaud told CNN. Whether this brain damage is permanent could not be determined in the study, so further investigations are needed.
It is also unclear which virus variant the subjects were suffering from. It is likely that most people were infected with the alpha variant because this was prevalent in Great Britain during the study period. But they can also have been infected with beta or gamma. The researchers consider an infection with the Delta variant to be unlikely. It also remains unclear to what extent the vaccination has a protective effect, because there is no information on the vaccination status or whether brain scans from younger people would show similar abnormalities as in the examined age group between 51 and 81 years.
,
Source: Stern
