More specifically, a cognitive decline like the one that occurs between the ages of 50 and 70, which is also equivalent to ten IQ points * A similar phenomenon was known even before the epidemic, in patients after hospitalization in intensive care for other diseases as well, and the researchers want to investigate this mechanism
By Adam Hampshire' Professor of Restorative Neuroscience, Imperial College London and David Menon, Professor, Head of Anaesthesiology, University of Cambridge. Translation: Avi Blizovsky
Severe illness with Corona causes aging at a rate similar to that between the ages of 50 and 70, and is equivalent to losing more than ten IQ points. This is according to a study we conducted.
The effects are still detectable more than six months after the acute illness, and they pass, at best, gradually.
There is growing evidence that the coronavirus can cause lasting cognitive and mental health problems, with recovered patients reporting symptoms including fatigue, "brain fog", word recognition problems, sleep disturbances, anxiety and even post-traumatic stress disorder (PTSD) months after infection.
Another UK study found that one in seven people who took part in it reported symptoms that included cognitive difficulties 12 weeks after testing positive for COVID. A recent brain imaging study found that even mild or moderate illness can cause the brain to shrink. Only 15 of the 401 people who participated in the study were hospitalized.
Citizen science
Incidental findings from a major citizen science project (the Great British Intelligence Test) have shown that even mild cases can lead to persistent cognitive symptoms. However, these problems seem to increase with the severity of the disease. Indeed, it has been independently shown that between one-third and three-quarters of hospitalized patients report cognitive symptoms three to six months later.
The magnitude of these problems, and the mechanisms responsible for them, are still unclear. Even before the pandemic, it was known that a third of people who have a period of illness that requires hospitalization in intensive care suffer from objective cognitive deficits six months after hospitalization.
It is believed that the phenomenon is a result of the inflammatory response that the body produces to fight a serious illness, therefore the cognitive deficits seen in COVID can certainly be due to a similar phenomenon. However, there is evidence that Sars-cov-2, the virus that causes corona, can infect brain cells, so we cannot rule out a direct viral infection of the brain.
Other factors, such as hypoxia (low oxygen levels in the blood), may also play a role. It was also unclear whether the widespread problems in psychological health reported after COVID were part of the same problem as that which occurs after other diseases or represented a different phenomenon.
Forty-six patients
To characterize the type and magnitude of these cognitive impairments, and to better understand their relationship to acute disease severity and psychological health problems at later time points, we analyzed data from 46 recovered COVID patients. All received anti-coronavirus treatment in the ward or intensive care unit at Addenbrooke's Hospital in Cambridge, England.
Participants underwent detailed computerized cognitive testing an average of six months after their acute illness using the Cognitron platform. This assessment platform was designed to accurately measure various aspects of mental aspects such as memory, attention and drawing conclusions, and was used in the aforementioned citizen science study.
We also measured levels of anxiety, depression and PTSD. The data of the study participants was compared to a control group of people with the same sex, age and other demographic factors who were not hospitalized due to Corona.
The response of the Corona survivors was slow and less accurate compared to the control groups. These deficits faded slowly but were still detectable up to ten months after hospitalization. There was also a difference in the intensity of symptoms between those who were hospitalized in serious condition and needed a ventilator, but those who suffered from significant symptoms also suffered from these symptoms.
By comparing the patients we examined to the medical file data of 66,008 patients, we were able to estimate that the size of the cognitive loss is similar on average to that caused in the twenty years of aging between the ages of 50 and 70 or to the loss of ten IQ points.
The survivors scored particularly poorly in tasks such as "verbal analogical thinking" (completing analogies such as laces are to shoes as buttons are to...). They also showed slower processing speeds, similar to previous observations that showed a decrease in glucose consumption in key areas of the brain responsible for attention, complex problem solving and short-term memory.
While those recovering from severe coronavirus can show a wide spectrum of symptoms of poor mental health – depression, anxiety, post-traumatic stress, low motivation, fatigue, low mood and sleep disturbances – these were not associated with the objective cognitive deficits known from other diseases, suggesting different mechanisms .
What are the reasons?
Direct viral infection is a possible cause, but unlikely to be the main cause. Instead, it is likely to be a combination of contributing factors, including poor oxygen supply to the brain, blockage of large or small blood vessels due to clotting, and microscopic bleeding.
However, the new evidence suggests that the most important factor may be damage caused by the body's inflammatory response and the immune system. Anecdotal evidence from doctors in the field supports this conclusion that some neurological problems have become less common since the widespread use of steroids and other drugs that suppress the inflammatory response.
Regardless of the mechanism, our findings have significant implications for public health. About 40,000 people have been treated in intensive care because of corona in England alone, and many others have been hospitalized. It is possible that many others did not receive hospital treatment despite the serious illness due to the pressure on health services during the peak waves of the corona epidemic. This means that there are many people who still experience cognitive problems many months after they have recovered. We urgently need to look at what can be done to help these people. Research is now underway to address this problem.
However, if the picture we see in corona patients is indeed a replication of problems seen in other serious diseases, this provides an opportunity to understand the mechanisms responsible and investigate treatments.
to the article on The Conversation website
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One response
Are these people who were vaccinated and got sick, or those who were not vaccinated at all?
Is there any analysis regarding the extent of the vaccine's contribution to the prevention of cognitive impairment, even in the case of a serious illness (without hospitalization)?