The brains of coronary heart disease were altered – even after mild courses
Several studies have shown covid-19 can cause other changes in the brain – including in areas that affect the sense of smell. At least for those who have become seriously ill.
But how does the covid-19 brain actually work for those who have had a mild illness?
According to a new study, which has been published in Nature, it seems that it is itself the changes in the brain. The study shows that the brain becomes a little smaller – first and foremost in areas that are linked to the sense of smell.
– It is a very solid study, the best in the field, and therefore it is published in Nature, one of the leading journals. So I am very impressed, says Michael Eriksen Benros, professor of immunopsychiatry and head of research at the Psychiatric Center Copenhagen and the University of Copenhagen.
It is also the first study to scan both before and after infection with covid-19.
– And that is the main strength of this study: that they have compared the scans both before and after the infection, as well as with a control group, says Benros.
Daniel Kondziella, chief physician and clinical associate professor at the Department of Brain and Nerve Diseases at Rigshospitalet in Denmark, agrees that studying is interesting.
– It is an important study which shows that covid-19 has effects on the brain which can be seen at group level – but not necessarily at individual level. And this applies to special areas in the brain that have to do with processing the sense of smell, he says.
The sense of smell affects
The researchers performed brain scans from a total of 785 participants. The brains of the participants were scanned in two rounds.
- 401 of the participants were infected with corona between the two brain scans.
- 384 have not had corona.
The purpose of studies was to investigate how centers in the brain involved in the perception of odors reacted after coronary heart disease.
– When they look at brain scans on those who have had covid-19, they can see influences in areas related to the sense of smell. That’s the most important thing, says Michael Benros.
But what is the reason for the changes?
According to Benros, this suggests that loss of sense of smell may affect brain regions, but which has also been shown previously after loss of sense of smell which was not related to covid-19.
But it can also be the immune system’s reaction to the infection that can affect the brain.
It can also be a direct effect of SARS-CoV-2 virus on brain in some cases.
We are talking about very small changes
However, it is talk of small to moderate changes that was addressed by Michael Benros.
In the areas researching change, it was a 0.7 percent reduction of the area on average, and for the areas where it was the biggest change, it was 2 percent.
– This is equivalent to the areas of the brain being studied found changes, get 3.5 years of increased aging, he says:
– These are relatively small to moderate changes that they can just show because it is such a large study, but it is relevant because so many have been infected.
Three important reservations
It is precisely the fact that we are talking about such small changes that is worth making, says Daniel Kondziella.
– These changes are very subtle. It’s not something you could see in individual patients, but just in large groups, he says.
Nor has it been proven that it is the virus that has caused the changes directly.
“It is likely that the SARS-COV-2 virus affects odor genes and that this has indirect effects on the brain,” he said.
The study shows that these changes exist relatively shortly after covid-19.
– It is uncertain how long the changes will last. It is entirely possible that the changes are temporary, says Daniel Kondziella.
More research provides more answers
Michael Benros agrees. The participants who received covid-19 have, on average, been scanned for the second time 4.5 months after they became infected.
– But right now this study is the best we have. Later, larger studies are likely to follow up over time.
We also do not know if these changes have an impact on the individual, says Daniel Kondziella.
– We know that covid-19 can lead to concentration problems and the like, but it is absolutely not certain that these changes are the cause, says Kondziella.
Small changes, but an important study
Still, it is “a hugely important study,” says Michael Benros.
The question is whether the changes will normalize when you get back the sense of smell. Will the affected areas of the brain then become larger? And is it related to continued problems with the sense of smell?
“It’s not at all certain, these are permanent changes, and previous studies of people affected by the sense of smell that were not related to covid-19 have shown an increase in the affected brain areas after training the sense of smell,” says Benros.
Source:
Neurology: Examination of brain changes after COVID-19Nature (2022), DOI 10.1038 / s41586-022-04569-5
© Videnskab.dk. Translated by Lars Nygaard for forskning.no. Read the original case on videnskab.dk here.
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