The severe cognitive impact of COVID-19 is equivalent to 20 years of aging, according to the study

We all know that COVID-19 can cause persistent fatigue and brain fog. But one of the most rigorous examinations to date of the long-term cognitive impacts of severe infection has just yielded quite disturbing results.

In a study comparing 46 patients with severe COVID-19 with 460 matching controls, the researchers found that the mental impacts of severe COVID-19 six months later could be the equivalent of 20 years of age, from 50 to 70 years, or lose 10 IQ points. .

Specific mental changes were also different from those observed in early dementia or general aging.

“Cognitive impairment is common in a wide range of neurological disorders, including dementia and even routine aging, but the patterns we saw – COVID-19’s ‘cognitive fingerprint’ – were different from all of these.” , says neuroscientist David Menon of the University of Cambridge in the UK, who was the lead author of the study.

The new paper is not intended to alarm many of us who have already had COVID, but rather to investigate more closely the severity of cognitive changes after severe cases of infection so that we can begin to understand how to mitigate them.

“Tens of thousands of people have undergone intensive care with COVID-19 in England alone and many more will have been very ill but not hospitalized,” says lead researcher and cognitive scientist Adam Hampshire of Imperial College. of London.

“This means that there are a large number of people who still have cognition problems many months later. We need to look urgently at what can be done to help these people.”

The experiment involved 46 people who had gone to Addenbrooke Hospital in Cambridge as a result of COVID-19 between March and July 2020. Sixteen of them received mechanical ventilation during their stay.

An average of six months after their infection, the researchers monitored them using a test tool called Cognitron to see how they were in areas such as memory, attention, reasoning, as well as anxiety, depression, and anxiety. post-traumatic stress disorder.

The researchers had no test results before these people became ill with COVID for comparison. Instead, they did the next best and compared their results with an equal control group of 460 people.

These results were then mapped to see how far they deviated from the expected scores for their age and demographics, based on 66,008 members of the general public.

The results showed that those who had survived severe COVID were less accurate and had slower response times than the general public.

The magnitude of cognitive loss was similar to the effects of aging between the ages of 50 and 70, and equivalent to losing 10 IQ points.

Accuracy in verbal analogy tasks, where people are asked to find similarities between words, was further affected. This reflects anecdotal reports suggesting that people after the infection are struggling to find the right word and have the feeling that their brain is in slow motion.

Interestingly, although patients reported different levels of fatigue and depression, the severity of the initial infection, rather than the current mental health of the survivor, could better predict the cognitive outcome, the team found.

“These results indicate that, although both fatigue and mental health are chronic chronicles [consequences] of COVID-19, its severity is likely to be somewhat independent of the observed cognitive deficits, “the researchers write in their article.

The good news is that after the follow-up, there were some signs of recovery, but at best it was gradual.

“We followed some patients for up to ten months after their acute infection, so we could see a very slow improvement,” Menon says.

“While this was not statistically significant, it is at least going in the right direction, but it is very possible that some of these individuals will never fully recover.”

This study only looked at the most extreme of hospitalized patients, but there are many other studies that show that even “mild” cases can cause similar cognitive impacts.

What is not yet fully understood is why and how the SARS-CoV-2 virus causes this cognitive decline.

Previous research has shown that during severe COVID-19, the brain decreases glucose consumption in the frontoparietal network, which is involved in attention, problem solving, and working memory. It is also known that the virus can directly affect the brain.

But researchers suggest that the likely culprit is not direct infection, but a combination of factors: including reduced oxygen or blood supply to the brain; vessel coagulation; and microscopic hemorrhages.

There is also growing evidence that the body’s own immune and inflammatory response can have a significant impact on the brain.

“Future work will focus on mapping these cognitive deficits to the underlying neuronal pathologies and inflammatory biomarkers, and longitudinal follow-up of recovery to the chronic phase,” the researchers write.

Until then, take comfort in the fact that if you’re still feeling slow and foggy months after recovering from COVID-19, you’re probably not alone.

The research has been published in eClinical Medicine.

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