Covid Discovers New Research That Can Cause Changes In The Brain

Covid-19 can cause more gray matter loss and tissue damage in the brain than it naturally occurs in people who are not infected with the virus. New research find.

Published in Nature on Monday, the study is believed to be the first study involving people who had brain scans both before and months after being infected with Covid. Neurological experts who were not involved in the study said it was worthwhile and unique, but the impact of the change is unclear and people may not necessarily have permanent damage. A function that warns that it does not suggest that changes can have serious effects on thoughts, memories, etc.

This study of people aged 51-81 years showed contractions and tissue damage, primarily in areas of the brain related to the sense of smell. Some of those areas are also involved in other brain functions, the researchers said.

“For me, this is pretty compelling evidence that something changes in the brains of this entire group of people with Covid,” said Serena Spditch, Head of Neuroinfection and Global Neurology at Yale School of Medicine. The doctor said. study.

But she warned: We don’t want to scare the general public. “Oh, this is evidence that everyone is damaging the brain and unable to function.”

The survey was attended by 785 participants from UK Biobank, a repository of approximately 500,000 medical and other data in the United Kingdom. Each participant underwent two brain scans approximately every three years and some basic cognitive tests. During the two scans, 401 participants tested positive for coronavirus and were all infected between March 2020 and April 2021.

The other 384 participants formed a control group because they were not infected with the coronavirus and had similar characteristics to those infected in areas such as age, gender, medical history, and socioeconomic status. Did.

With normal aging, people lose a small portion of their gray matter each year. For example, in memory-related areas, the typical annual loss is between 0.2% and 0.3%, the researchers said.

However, Covid patients in this study who received a second brain scan on average four and a half months after infection lost more than uninfected participants, 0.2% to 2% in different brain regions over three years. Experienced additional gray matter loss. Between scans. They also lost more overall brain volume and showed more tissue damage in certain areas.

Dr. Spditch, who studied the neurological effects of Covid, said: “You wouldn’t have expected that much change,” she added.

This effect is particularly significant because this study primarily targeted people who were mildly affected by the initial Covid infection and did not become ill enough to require hospitalization, such as the majority of Covid patients in the general population. Notable.

Gwenaëlle Douaud, the lead author of the study and a professor of clinical neuroscience at Oxford University, said the study had too few inpatients to provide definitive data, but the results were in their brains. He said it suggests atrophy. It was worse than a mild patient.

People who had Covid also showed greater decline than uninfected people in cognitive tests related to attention and efficiency in performing complex tasks. However, outside experts and Dr. Douaud said the cognitive test was rudimentary, so a study of whether the gray matter loss and tissue damage experienced by Covid patients affected cognitive skills. Very limited.

Dr. Benedict Michael, an associate professor of neuroinfectious diseases at the University of Liverpool, said: It was a neuropsychiatric effect of Covid and was not involved in the study. “We don’t know what that really means for the patient’s quality of life or function.”

For example, some of the largest gray matter losses were in the orbitofrontal cortex, parahippocampal gyrus, and other areas related to the sense of smell, but these areas are also involved in memory and other functions. However, Dr. Douaud said that Covid patients performed worse than participants who were not infected with memory tests, but added that the memory tests they received were concise and basic.

The main cognitive assessments in which Covid patients showed a deficit Trail making test, Dot to dots type exercises that use letters and numbers alternately. Covid patients took a long time to complete the task. This may indicate weaknesses in focus, processing speed, and other skills.

Dr. Douaud said this diminished capacity correlates with the loss of gray matter in certain areas of the cerebellum of the brain. However, the study does not prove the cause and effect, Dr. Spditch said. The cerebellum is primarily associated with balance, coordination, and movement, and was “not the first brain structure you think of” to explain changes in ability. Trail making test.

One of the key limitations of this study was that researchers did not have information about people’s symptoms, such as whether they lost their sense of smell. Researchers also couldn’t determine if Covid had long-term patients, so it’s unclear if the findings are related to their long-term condition.

The difference between infected and uninfected increased with age. For example, in the Trail Making Test, both groups in their 50s and early 60s performed the same, but the gap widened significantly thereafter. “I don’t know if it’s a quick recovery for young people or if it wasn’t affected in the first place,” said Dr. Duo. “It could be either or both.”

Dr. Michael warned that the findings cannot be extrapolated to many young people experiencing post-covid brain fog and other cognitive problems. “I don’t know if it’s a temporary change that improves with recovery,” he said, because gray matter and tissue damage were measured at only one point in time after infection.

External experts and study authors said the range of brain regions in which Covid patients experience more gray matter loss raises interesting questions.

“There is no part of the brain that does one thing,” said Dr. Douaud. “Some parts of the infected participants’ brains have additional loss of gray matter that is not related to the sense of smell, and those related to the sense of smell are also involved in other brain functions.”

The cause of the brain changes is unknown.The author mentioned a theory that included: Inflammation, evidence found in other studiesAnd “sensory deprivation” from the disturbance of the sense of smell.

Another “important question,” said Dr. Avindra Nath, head of the Nervous System Infections section of the National Institute of Neurological Disorders and Stroke, who was not involved in the study, said that brain changes tended to be more prone to Covid patients. Said whether it could be possible to have dementia and other deficits in the future.

Researchers did not find the same brain changes in patients with non-Covid pneumonia, but Dr. Nath recommended studying patients with other coronaviruses or flu.

Dr. Spditch said the greatest value of this study could indicate that “something happened in the brains of these people,” and “people say it’s very vague and difficult to measure.” I think I feel it. “

Other scientists can now build on these discoveries, she and others said.

“This is an important study and they did a good job,” Dr. Michael added. Patience. “