Our latest study showed that severe COVID leads to cognitive impairment between the ages of 50 and 70 and is equivalent to a loss of ten IQ points. The effects are more pronounced after more than six months of severe illness, and recovery is, at best, gradual.
Evidence is growing that COVID can cause long-term cognitive and mental health problems, with patients recovering from fatigue, brain fog, memory problems, sleep disturbances, anxiety, and even post-traumatic stress disorder months after infection. PTSD).
A study in the UK found that one in seven people surveyed said they had symptoms of cognitive impairment 12 weeks after a positive COVID test. A recent study of brain imaging showed that mild COVID can also cause brain shrinkage. Of the 401 people surveyed, only 15 were hospitalized.
Coincidences from a major civic science project (UK intelligence test) have also shown that mild cases can lead to persistent cognitive symptoms. However, these problems increase with the severity of the disease. In fact, three-quarters of hospitalized patients showed self-reported cognitive symptoms after three to six months.
The magnitude and responsibilities of these problems remain unclear. Even before the pandemic, it was known that one-third of people with an episode of illness requiring admission to the ICU showed an objective cognitive deficit six months after admission.
This is thought to be the result of an inflammatory reaction associated with a critical illness, and the cognitive deficit observed in COVID may be a similar phenomenon. However, there is evidence that the virus that causes SARS-CoV-2, COVID, can infect brain cells. We cannot rule out a direct viral infection of the brain.
Other factors, such as hypoxia (lack of oxygen in the blood), may also play a role. It is also unclear whether the widespread psychological health problems reported after COVID were part of the same problem as objective cognitive deficits or meant another phenomenon.
To characterize the type and magnitude of these cognitive impairments and to better understand their relationship to the severity of the acute phase of the disease and subsequent psychological health problems, we analyzed data from 46 previous COVID patients. All of them were treated at the ward for COVID at Addenbrook Hospital in Cambridge, England, or at the hospital at ICU.
Participants underwent detailed computerized cognitive tests six months after the Cognitron platform. This assessment platform was developed to accurately measure various aspects of mental abilities such as memory, attention, and reasoning, and was used in the study of civic science mentioned above.
We also measured levels of anxiety, depression and PTSD. The data of the study participants were compared with the corresponding authorities – homosexuality, age and other demographic factors, but not hospitalized with COVID.
COVID survivors reacted more vaguely and more slowly than matching controls. These deficiencies gradually resolve and persist for up to ten months after hospitalization. The effects depend on the severity of the disease and the markers of inflammation. They were stronger for those who required mechanical ventilation, but also more serious for those who did not.
By comparing patients with 66,008 members of the community, we were able to determine that the magnitude of cognitive impairment was similar in those aged 20 to 50 to 70 years. This is equivalent to losing ten IQ points.
Survivors received poor grades, especially in tasks such as “verbal analog thinking” (completion of analogies such as strap on, what steps are needed for shoes …). They also showed slower processing speeds, which is consistent with previous post-COVID observations of reduced cerebral glucose consumption in key areas of the brain responsible for attention, complex problem solving, and working memory.
People recovering from severe COVID may have a wide range of symptoms of poor mental health – depression, anxiety, post-traumatic stress, low motivation, fatigue, low mood, and sleep disturbances – suggest different mechanisms that are not related to objective cognitive deficits.
What are the reasons?
There may be a direct viral infection, but it may not be the root cause. Instead, a combination of these factors, including a lack of oxygen or blood to the brain, blockage of large or small blood vessels due to blood clotting, and microscopic bleeding can be the cause.
However, the evidence suggests that the most important mechanism may be damage to the body’s inflammatory response and the immune system. Anecdotal evidence from frontline neurologists supports the conclusion that some problems have become less common since the widespread use of corticosteroids and other anti-inflammatory drugs.
Regardless of the mechanism, our findings have significant implications for public health. In the UK alone, about 40,000 people have received intensive care with COVID and many more have been hospitalized. As the pandemic wave intensifies, the health care system is in a state of flux, and many other people may not be treated in the hospital despite their serious illness. This means that after a few months there are still many people who have problems with cognition. We urgently need to consider what can be done to help these people. Research is now underway to address this issue.
However, there is something about the silver cap. If, as we suspect, the image we see in COVID really repeats a broader problem observed in other types of severe disease, it will allow us to understand the responsible mechanisms and explore treatment options.
This article was republished in The Conversation magazine under a Creative Commons license. Read the original article.