From forgetfulness to difficulties concentrating, many people who have long COVID experience “brain fog.” Now researchers say the symptom could be down to the blood-brain barrier becoming leaky.
The barrier controls which substances or materials enter and exit the brain.
“It’s all about regulating a balance of material in blood compared to brain,” said Matthew Campbell, co-author of the research at Trinity College Dublin.
Photo: AP
“If that is off balance then it can drive changes in neural function and if this happens in brain regions that allow for memory consolidation/storage then it can wreak havoc.”
Writing in the journal Nature Neuroscience, Campbell and colleagues report how they analyzed serum and plasma samples from 76 patients who were hospitalized with COVID in March or April 2020, as well 25 people before the pandemic.
Among other findings, the team discovered that samples from the 14 COVID patients who self-reported brain fog contained higher levels of a protein called S100β than those from COVID patients without this symptom, or people who had not had COVID.
This protein is produced by cells within the brain, and is not normally found in the blood, suggesting these patients had a breakdown of the blood-brain barrier.
The researchers then recruited 10 people who had recovered from COVID and 22 people with long COVID — 11 of whom reported having brain fog. None had, at that point, received a COVID vaccine, or been hospitalized for COVID.
These participants underwent an MRI scan in which a dye was administered intravenously.
The results reveal long COVID patients with brain fog did indeed show signs of a leaky blood-brain barrier, but not those without this symptom, or who had recovered.
Campbell added that it was possible people with a tighter blood-brain barrier might be better protected from brain fog should they develop long COVID, explaining why the symptom did not arise in all patients.
Further work in a subgroup of participants revealed long COVID patients with brain fog also showed signs of increased levels of proteins involved in clotting.
Campbell said the results were not a surprise as disruptions to proteins involved in clotting could go hand in hand with disruption to cells that lined blood vessels. “The whole concept that a lot of these neurological conditions, including brain fog, could be treated by simply regulating the integrity of the blood-brain barrier is really exciting,” he said.
While the study focuses on long COVID patients, Campbell said the results might have relevance to people with brain fog relating to other conditions — such as ME — although extensive work would be needed to confirm that.
Paul Harrison from the University of Oxford, an author of earlier work suggesting blood clots in the brain may be one cause of brain fog in people with long COVID, said the new study was important.
“It shows that abnormalities in the lining of blood vessels in the brain occur in people with post-COVID brain fog, and adds to the evidence that abnormal blood clotting also contributes,” he said.
But he added that the results came from patients who had COVID in the first wave, meaning it was plausible but unclear whether the same mechanisms occurred in others, such as those with later variants of the virus, or who were vaccinated.
Harrison said: “Likely, a range of processes explain brain fog and other features of post-COVID syndrome.”
Claire Steves of King’s College London said the small number of participants involved meant it was possible that findings of differences between groups were due to chance, while brain fog was not clearly defined and was self-reported by participants.
“Therefore it is difficult to be sure how applicable these results are to the millions of people who have experienced this phenomenon,” she said.
If you are a Western and especially a white foreign resident of Taiwan, you’ve undoubtedly had the experience of Taiwanese assuming you to be an English teacher. There are cultural and economic reasons for this, but one of the greatest determinants is the narrow range of work permit categories that exist for Taiwan’s foreign residents, which has in turn created an unofficial caste system for foreigners. Until recently, laowai (老外) — the Mandarin term for “foreigners,” which also implies citizenship in a rich, Western country and distinguishable from brown-skinned, southeast Asian migrant laborers, or wailao (外勞) — could only ever
Sept. 23 to Sept. 29 The construction of the Babao Irrigation Canal (八堡圳) was not going well. Large-scale irrigation structures were almost unheard of in Taiwan in 1709, but Shih Shih-pang (施世榜) was determined to divert water from the Jhuoshuei River (濁水溪) to the Changhua plain, where he owned land, to promote wet rice cultivation. According to legend, a mysterious old man only known as Mr. Lin (林先生) appeared and taught Shih how to use woven conical baskets filled with rocks called shigou (石笱) to control water diversion, as well as other techniques such as surveying terrain by observing shadows during
In recent weeks news outlets have been reporting on rising rents. Last year they hit a 27 year high. It seems only a matter of time before they become a serious political issue. Fortunately, there is a whole political party that is laser focused on this issue, the Taiwan Statebuilding Party (TSP). They could have had a seat or two in the legislature, or at least, be large enough to attract media attention to the rent issue from time to time. Unfortunately, in the last election, Taiwan People’s Party (TPP) Chairman Ko Wen-je (柯文哲) acted as a vote sink for
This is a film about two “fools,” according to the official synopsis. But admirable ones. In his late thirties, A-jen quits his high-paying tech job and buys a plot of land in the countryside, hoping to use municipal trash to revitalize the soil that has been contaminated by decades of pesticide and chemical fertilizer use. Brother An-ho, in his 60s, on the other hand, began using organic methods to revive the dead soil on his land 30 years ago despite the ridicule of his peers, methodically picking each pest off his produce by hand without killing them out of respect