They called it "mind fog" and it could affect one in 20 patients recovered from Covid, even for weeks or months after infection. Symptoms range from lack of attention and concentration to impaired short-term memory. What we know
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Covid-19 identified by the authors (photo: elenaleonova via Getty Images) Research on the aftermath of the coronavirus and on the symptoms and disorders that persist for weeks or months after healing - the so-called long Covid - they are now accumulating. Today at the attention of various research groups there is a new problem, defined by the media in recent days as brain fog or mental fog, which would affect some patients who have had even mild Covid-19. According to a large sample of data, it would concern 1 in 20 people, not necessarily of advanced age, but often also young. Confusion, lack of concentration, attention and memory difficulties are some of the symptoms that persist for weeks. The problem has emerged very recently and there are still no large and structured studies, but already some research groups in various parts of the world have collected some evidence. Here's what we know.
Memory and concentration
We know that Covid-19 can affect the brain in a very serious way, even with stroke and encephalitis. But the infection can also cause other, milder neurological manifestations, such as headache and loss of smell and taste, which can persist. But psychological and cognitive symptoms can also arise. There are testimonials from recovered patients who don't remember the content of conversations they just had or what happened in the last few days, documents an article in the New York Times. "It's a bit like I have dementia," says a 53-year-old patient in the text of the article in the NYT. Then there are those who feel confusion, those who cannot concentrate, those who cannot find the words. These are disturbing disorders but it must be emphasized that the problem is probably transitory and that not only the Sars-Cov-2 coronavirus infection can cause temporary cognitive problems of this kind.
Mental fog, from where does the estimate come from
A survey conducted by Massachusetts General Hospital, Harvard Medical School, and King's College London analyzed data, collected via an app, of nearly 4 million people. The results show that nearly one in 20 people continue to have symptoms that fall within the definition
of long Covid, including "mental fog", 8 weeks after infection.
Others studies on mind fog
A Chinese research by Zhejiang University School of Medicine, conducted on 29 patients and recently published in the Journal of Psychiatric Research, demonstrates the presence of a persistent alteration in sustained attention, or the ability to maintain vigilance and paying attention to important information while performing a task and throughout its duration. The sample is small and not representative of the entire population. A French study by the University of Paris, which analyzed data from 120 patients hospitalized and then cured, found that for months after recovery, 34% continued to have memory problems and 27% concentration. Also in this case the sample is small and we are dealing with hospitalized patients, therefore with severe forms. Then there is a Canadian survey - not yet published but in the process of being published - on 3,390 former patients (Survivor Corps, survivors of Covid) which indicates, according to what was reported by Natalie Lambert, coordinator of the study at the Indiana University School of Medicine, that more than half of the participants have difficulty concentrating or focusing.
The causes, still unknown
The causes of mental fog are not yet known. Reporting your symptoms to your doctor, even when it comes to cognitive impairments, can be very important in increasing and spreading knowledge about the problem. Many symptoms - including temporary loss of smell and dermatological manifestations - were officially associated with the coronavirus initially thanks to patient reports. One of the hypotheses underlying cognitive clouding is a persistent activation of the immune system, even after infection. The inflammatory molecules our body produces could act as toxins, including for the brain, as Serena Spudich, head of the Department of Neurological Infections and Global Neurology at Yale School of Medicine, explained in the New York Times.
The long Covid: from tiredness to mental fatigue
Cognitive symptoms are only one possible face of the long Covid. Recall that it is estimated that one third of patients (especially the most severe) will have chronic lung damage, but the negative effects can affect various organs and body tissues, including the brain, cardiovascular system, liver, kidneys and not only . Then there are those who experience persistent fatigue (post-viral fatigue syndrome), muscle pain and weakness and breathlessness.
