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Does Covid Affect The Brain

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How does coronavirus affect the brain?

For instance, a recent US study that analysed brain tissue from eight patients who died from COVID-19 found no traces of the virus in the samples.

But the research did find more signs of inflammation in the brain tissue of COVID-19 patients than the control group, suggesting that inflammatory responses triggered by the virus in other parts of the body can kickstart inflammation in the brain.

Tissa Wijeratne, a neurologist at the University of Melbourne, has also found inflammatory markers linked with the immune response in the blood of patients who experience neurological issues months after they were first infected with the virus.

The virus doesn’t have to go to the brain to make an impact, said Professor Wijeratne, who is currently investigating the long-term neurological effects of COVID-19.

My hypothesis is that this is largely driven by a maladaptive, persistent low-grade immune reaction.

Supplied: Tissa Wijeratne

And while it’s too early to know for sure, there’s a strong possibility that inflammation could be one of the main culprits behind lingering neurological symptoms, said the George Institute’s Professor Anderson.

We know that severe viral infections can cause inflammation in the brain, he said.

For instance, the stress of having the infection itself could also have an effect on the brain and cognition, particularly for those who have been in hospital, said Professor Hannan.

Signs Covid Is In Your Brain

    With more than 18 months of the pandemic in the rearview mirror, researchers have been steadily gathering new and important insights into the effects of COVID-19 on the body and brain. These findings are raising concerns about the long-term impacts that the coronavirus might have on biological processes such as aging.

    As a cognitive neuroscientist, my past research has focused on understanding how normal brain changes related to aging affect people’s ability to think and move particularly in middle age and beyond. But as more evidence came in showing that COVID-19 could affect the body and brain for months or longer following infection, my research team became interested in exploring how it might also impact the natural process of aging. Read on to find out moreand to ensure your health and the health of others, don’t miss these Sure Signs You May Have Already Had COVID.

    Peering In At The Brain’s Response To Covid

    In August 2021, a preliminary but large-scale study investigating brain changes in people who had experienced COVID-19 drew a great deal of attention within the neuroscience community.

    In that study, researchers relied on an existing database called the UK Biobank, which contains brain imaging data from over 45,000 people in the UK going back to 2014. This means crucially that there was baseline data and brain imaging of all of those people from before the pandemic.

    The research team analyzed the brain imaging data and then brought back those who had been diagnosed with COVID-19 for additional brain scans. They compared people who had experienced COVID-19 to participants who had not, carefully matching the groups based on age, sex, baseline test date and study location, as well as common risk factors for disease, such as health variables and socioeconomic status.

    The team found marked differences in gray matter which is made up of the cell bodies of neurons that process information in the brain between those who had been infected with COVID-19 and those who had not.

    Specifically, the thickness of the gray matter tissue in brain regions known as the frontal and temporal lobes was reduced in the COVID-19 group, differing from the typical patterns seen in the group that hadn’t experienced COVID-19.

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    Infecting Neurons With Devastating Consequences

    Other researchers have focused on how the new coronavirus infects neurons and damages brain tissue.

    For example, a team led by Akiko Iwasaki, the Waldemar Von Zedtwitz Professor of Immunobiology and Molecular, Cellular, and Developmental Biology at the Yale School of Medicine, in New Haven, CT, used lab-grown, miniature 3D organ reproductions to analyze how SARS-CoV-2 invades the brain.

    The study, which appears in the Journal of Experimental Medicine, showed that the new coronavirus was able to infect neurons in these lab-grown organoids and replicate itself by boosting the metabolism of infected cells. Simultaneously, healthy, uninfected neurons in the vicinity died as their oxygen supply was cut off.

    The researchers also determined that blocking the ACE2 receptors prevented the virus from infecting the human brain organoids.

    The scientists also analyzed the effects of SARS-CoV-2 on the brains of mice genetically modified to produce human ACE2 receptors. Here, the virus altered the brains vasculature, or blood vessels. This could, in turn, cut off the brains oxygen supply.

    Furthermore, the mice with an infection that had spread to the brain had much more severe illness than those with an infection limited to the lungs.

    New Research Shines Light On How Covid

    How does COVID

      getty

      Its no secret that Covid-19 infections can have an effect on the neurological system. From the early days of the pandemic, reports of brain fog, memory issues and confusion showed that the virus impacts much more than the lungs. But what do we really know about how Covid-19 can damage the brain? Research presented at the Alzheimers Association International Conference on July 29 sheds some light on how Covid-19 impacts brain function.

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      Warning Signs Covid Is Ruining Your Brain

        By now, we know that COVID-19 isn’t just a simple respiratory diseaseit affects a wide range of body systems. In particular, doctors are learning more and more about its potentially devastating effect on the brain: In one study conducted at Northwestern University, one-third of hospitalized COVID patients showed signs of altered mental function, including confusion and delirium. Those patients stayed in the hospital three times longer, and only 32 percent of them were able to resume normal daily activities after being discharged. Experts think this may be triggered by the virus’s tendency to cause inflammation and impair blood circulation. These are some of the scary neurological symptoms associated with COVID. Read on, and to ensure your health and the health of others, don’t miss theseSure Signs You’ve Already Had Coronavirus.

        Once It Infects The Brain It Can Affect Anything

        Another study supports the idea that COVID-19s attack on the brain is what makes the disease very severe.

        A team of researchers, including senior study author Mukesh Kumar, a virologist specializing in emerging infectious diseases and assistant professor at Georgia State University, in Atlanta, infected the nasal passages of mice with the new coronavirus. This caused severe illness in the rodents, even after the infection had cleared from their lungs.

        The scientists then analyzed levels of the virus in several organs, comparing the intervention group of mice with a control group, which had received a dose of saline solution instead of the virus.

        The results published in the journal Viruses revealed that viral levels in the lungs peaked around day 3 after the infection, but levels in the brain persisted on days 5 and 6, coinciding with the symptoms being most severe and debilitating. The scientists also found that the brain contained 1,000 times higher levels of the virus than other parts of the body.

        This may explain, the senior researcher says, why some people seem to recover after a few days and have improved lung function, only to then relapse and have more severe symptoms, some of which can prove lethal.

        The brain is one of the regions where viruses like to hide, he continues, because unlike the lungs, the brain is not as equipped, from an immunological perspective, to clear viruses.

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        What Did The Researchers Do

        The study analyzed health information from 3,744 people who had been hospitalized with COVID-19. Participants were identified through the Global Consortium Study of Neurologic Dysfunction in COVID-19 and the European Academy of Neurologys Neuro-COVID Registry .

        The researchers looked at the participants hospitalization records for many possible neurological effects, including self-reported symptoms such as headache and loss of taste or smell and symptoms observed by hospital staff, such as fainting, coma, seizure, encephalopathy , meningitis, and aphasia .

        What Is Brain Fog

        The Science Behind How the Coronavirus Affects the Brain | WSJ

        Brain fog refers to problems with thinking, memory and concentration, but for many patients, it can be challenging to describe.

        Patients often say they just dont feel right, says Talya Fleming, M.D., medical director, Post-COVID Rehabilitation Program at JFK Johnson Rehabilitation Institute. We use the term fog because patients feel that something is over them that is making things not as crisp or distinct as they were before.

        I have heard patients say they have trouble with memory, are easily distracted, have trouble following a conversation, and have difficulty concentrating and attending to everyday tasks, explains Kristie R. Soriano, MS, CCC/SLP, manager of Outpatient Speech Programs at JFK Johnson Rehabilitation Institute.

        Symptoms of brain fog may also appear as:

        • Walking into a room and forgetting why you are there
        • Losing your train of thought
        • Difficulty thinking of the right words
        • Difficulty remembering what you just read
        • Taking longer to complete tasks
        • Forgetting recipes or steps when cooking
        • Leaving lights or appliances on unintentionally
        • Forgetting what you were doing after becoming distracted

        These symptoms often emerge after patients get through the medical emergency and go back to work, comments Soriano. In many cases, patients are having trouble functioning on the job or managing day-to-day responsibilities, which can negatively impact their quality of life.

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        Trial Studying Technique To Clear Brain Fog After Covid

        A new clinical trial at UAB aims to improve cognitive function in patients with “brain fog” and other lingering cognitive symptoms after they have recovered from COVID-19.Even after their bodies have cleared the virus that causes COVID-19, many patients experience long-term effects. One of the most troubling is a change in cognitive function commonly called brain fog that is marked by memory problems and a struggle to think clearly. A new clinical trial at UAB is testing a proven rehabilitation method to remedy that.

        A report on 120 patients in France, , found that more than a third had memory loss and 27% had cognitive difficulties months after recovering from COVID-19. In another study, a hospital network in Chicago reported that, among 509 patients, nearly a third experienced altered mental function of these, 68% were unable to handle routine daily activities such as cooking or paying bills.

        What is it like to live in the fog?

        One physician described it as akin to the fuzzy-headed feeling the day after a sleepless night. A researcher in the United Kingdom, discussing an initial report on more than 84,000 people, said in severe cases it is as if the brain had aged 10 years, almost overnight. Patients talking to the New York Times said it is debilitating, it feels as though I am under anesthesia and everything in my brain was white static. Several described how the brain fog has made it difficult or impossible for them to return to work.

        Clots Strokes And Rashes Is Covid

        To understand other, less obvious mechanisms, though, scientists needed brain tissue from patients with COVID-19 who died. And early in the pandemicthey couldn’t get that tissue, says Dr. Avindra Nath of the National Institute of Neurological Disorders and Stroke.

        “Because it was such an infectious organism, people were not conducting autopsies at most places,” Nath says. They simply lacked the protective gear that would allow them to remove a brain safely.

        That’s changing, though, says Nath, who was part of a team that studied brain tissue from 19 COVID-19 patients.

        The team saw widespread evidence of inflammation and damage, they reported Dec. 30 in TheNew England Journal of Medicine.

        They also found a possible explanation for the damage.

        “What we found was that the very small blood vessels in the brain were leaking,” Nath says. “And it wasn’t evenly you would find a small blood vessel here and a small blood vessel there.”

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        Breaking Into The Brain

        SARS-CoV-2 can have severe effects: a preprint posted last month compared images of peoples brains from before and after they had COVID-19, and found loss of grey matter in several areas of the cerebral cortex.

        Early in the pandemic, researchers speculated that the virus might cause damage by somehow entering the brain and infecting neurons, the cells responsible for transmitting and processing information. But studies have since indicated that the virus has difficulty getting past the brains defence system the bloodbrain barrier and that it doesnt necessarily attack neurons in any significant way.

        One way in which SARS-CoV-2 might be accessing the brain, experts say, is by passing through the olfactory mucosa, the lining of the nasal cavity, which borders the brain. The virus is often found in the nasal cavity one reason that health-care workers test for COVID-19 by swabbing the nose.

        Even so, theres not a tonne of virus in the brain, says Spudich, who co-authored a review of autopsies and other evidence that was published online in April.

        But that doesnt mean it is not infecting any brain cells at all.

        Astrocytes are star-shaped cells in the central nervous system that perform many functions, including providing nutrients to neurons.Credit: David Robertson, ICR/SPL

        How Does Covid Damage The Brain

        COVID

        These nasal sensory cells connect to an area of the brain known as the limbic system, which is involved in emotion, learning and memory.

        In a UK-based study released as a pre-print online in June, researchers compared brain images taken of people before and after exposure to COVID. They showed parts of the limbic system had decreased in size compared to people not infected. This could signal a future vulnerability to brain diseases and may play a role in the emergence of long-COVID symptoms.

        COVID could also indirectly affect the brain. The virus can damage blood vessels and cause either bleeding or blockages resulting in the disruption of blood, oxygen, or nutrient supply to the brain, particularly to areas responsible for problem solving.

        The virus also activates the immune system, and in some people, this triggers the production of toxic molecules which can reduce brain function.

        Although research on this is still emerging, the effects of COVID on nerves that control gut function should also be considered. This may impact digestion and the health and composition of gut bacteria, which are known to influence the function of the brain.

        The virus could also compromise the function of the pituitary gland. The pituitary gland, often known as the master gland, regulates hormone production. This includes cortisol, which governs our response to stress. When cortisol is deficient, this may contribute to long-term fatigue.

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        What Did They Learn

        Neurological effects were extremely common, appearing in about 80% of patients who had been hospitalized with COVID-19. The most common symptoms reported by patients were headache, which affected 37% of participants, and loss of taste or smell, which affected 26%. The most common neurological problems observed in patients by hospital staff were acute encephalopathy , coma , and stroke .

        Patients whose neurological symptoms were observed by hospital staff were more likely to die in the hospital than people with self-reported neurological symptoms likely because symptoms reported by hospital staff occur in more severe cases of COVID-19. The researchers also found that people with preexisting neurological conditions such as chronic migraines, brain or nerve diseases, or dementia were more likely to have neurological symptoms of COVID-19 than other people were.

        Adopt Or Maintain Good Health Habits

        Its always essential to control blood pressure, diabetes, and any other underlying health issues you may have, advises Dr. Danoun. Avoid smoking and alcohol, eat a healthy diet, get enough rest. If you do contract COVID-19, all of these things will create a nourishing environment for your body to recover.

        Prioritizing sleep is of particular importance, as too little shuteye may weaken your defenses against a virus. As you await your chance to receive the COVID-19 vaccine, its helpful to know that sleep can also optimize your immune systems response to a vaccine, in part because its a great stress reducer and stress can hamper the bodys immune response. One study found that the flu vaccine appears to be more effective responses are quicker, more robust, and longer lasting in people who get a sufficient duration of sleep for the two nights prior to receiving the shot, and other studies have made similar findings in response to other vaccines.

        Finally, speak to your health care provider about which vitamin supplementation is important for you, Dr. Kuruvilla suggests. Some studies, though certainly not all, have shown that low vitamin D levels can leave you more vulnerable to COVID-19 and result in more severe disease.

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        Effect On The Brain Explains Loss Of Smell

        Dr. de Erausquin recently published a paper along with colleagues, including senior author Dr. Sudha Seshadri, a professor of neurology at the same institution and director of the universitys Glenn Biggs Institute for Alzheimers and Neurodegenerative Diseases.

        The basic idea of our study is that some of the respiratory viruses have affinity for nervous system cells, Prof. Seshadri explains. She adds, Olfactory cells are very susceptible to viral invasion and are particularly targeted by SARS-CoV-2, and thats why one of the prominent symptoms of COVID-19 is loss of smell.

        Olfactory cells are concentrated in the nose. Through them, the virus reaches the olfactory bulb in the brain, which is located near the hippocampus, a brain area involved in short-term memory.

        The trail of the virus, when it invades the brain, leads almost straight to the hippocampus, explains Dr. de Erausquin. That is believed to be one of the sources of the cognitive impairment observed in COVID-19 patients. We suspect it may also be part of the reason why there will be an accelerated cognitive decline over time in susceptible individuals.

        In their paper, the scientists refer to existing evidence that makes them particularly wary of SARS-CoV-2s impact on the brain. For example, researchers have found that:

        Other research adds to the concerns expressed by Dr. de Erausquin, Dr. Seshadri, and their colleagues specifically regarding the risk of delirium and coma.

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