Researchers from Heidelberg suspect that the cause of cognitive problems is a result of an infection in the hippocampus
Problems with memory and concentration, listlessness, fatigue and “fog in the head” are among the not so uncommon complaints that can persist or only occur following an acute infection with the coronavirus. In the case of Long Covid, they are even among the most frequently mentioned symptoms. It is still unclear what exactly causes such cognitive impairments, especially since they are not only observed following severe Covid-19 and in risk groups, but also in younger people and following relatively mild infections.
Researchers from the Faculty of Applied Psychology at the private SRH Hochschule Heidelberg have now found a possible explanation for these cognitive problems in their study “CogniCovid 19” and have shown for the first time which mechanism might be behind it. They assume that their results, which are soon to be published in a specialist journal, might pave the way for therapy.
For their study, the group led by Patric Meyer and Ann-Kathrin Zaiser, who teach neurocognitive psychology at the SRH Hochschule Heidelberg, examined around 1,500 people between July 2021 and July 2022, why symptoms such as impaired concentration developed following a corona infection , memory problems or fog in the head – and how exactly these manifest themselves. The result: The Heidelberg researchers suspect the cause of the cognitive impairments following a corona infection in the hippocampus. It is a part of the limbic system in the brain where new nerve cells are formed and where emotion processing, learning and memory formation take place.
The researchers assume that a part of the hippocampus called the dentate gyrus in particular plays a key role in cognitive problems following a corona infection. Among other things, the dentate gyrus produces different patterns of activity in response to events that are very similar, but not identical. This process is called pattern separation – and it helps you know, for example, where you parked your car or bike and not look for it where it was the day before.
Not only learning and memory are associated with the hippocampus, but also the regulation of stress and emotions – which is often changed following a corona infection, but also in mental illnesses such as depression. It is fitting that a team from Essen University Medicine found out last year that previous psychiatric illnesses such as depression or an anxiety disorder can significantly increase the risk of long Covid.
The team from the SRH Hochschule Heidelberg put forward the hypothesis “that the infection is subject to a similar mechanism to other stress-related diseases, namely an inflammatory process,” as Patric Meyer says. The reason for this: The virus can get into the blood and also reach the brain. There, according to the scientist, an overactive immune reaction can trigger inflammation, which in turn ensures that fewer nerve cells are formed in the hippocampus: “Our data indicate that precisely this reduced formation of new nerve cells plays a key role in the development of cognitive and affective impairments following a corona infection,” says Ann-Kathrin Zaiser. Young people are just as affected as older people.
However, the researcher already has an idea of how the problem might be tackled: “If we stimulate the process of neurogenesis once more, for example with certain medications, moderate exercise, cognitive tasks or a healthy diet, those affected can very likely improve their cognitive performance once more .”
