Analysing cerebrospinal fluid in people with post Covid conditions like brain fog may provide insights into how SARS-CoV-2 impacts the brain, suggests a study.Some patients who develop new cognitive symptoms such as brain fog even after a mild bout of Covid-19 tend to have abnormalities in their cerebrospinal fluid similar to those found in people with other infectious diseases.A team of researchers from University of California and Weill Cornell Medicine, conducted a small study, where they analysed the cerebrospinal fluid of 17 of participants.All participants had Covid but had not required hospitalisation.They found that 10 of 13 participants with cognitive symptoms had anomalies in their cerebrospinal fluid. But all four of the cerebrospinal samples from participants with no post-Covid cognitive symptoms were normal.
Participants with these symptoms presented with executive functioning issues, said senior author Joanna Hellmuth, from the UCSF Memory and Ageing Centre."They manifest as problems remembering recent events, coming up with names or words, staying focused, and issues with holding onto and manipulating information, as well as slowed processing speed," she said.The research was published in the Annals of Clinical and Translational Neurology.Examinations of the cerebrospinal fluid revealed elevated levels of protein, suggesting inflammation, and the presence of unexpected antibodies found in an activated immune system.Some were found in the blood and cerebrospinal fluid, implying a systemic inflammatory response, or were unique to the cerebrospinal fluid, suggesting brain inflammation.While the targets of these antibodies are unknown, it is possible that these could be "turncoat" antibodies that attack the body itself.
"It's possible that the immune system, stimulated by the virus, may be functioning in an unintended pathological way," said Hellmuth."This would be the case even though the individuals did not have the virus in their bodies," she said.The researchers also found that the participants with cognitive symptoms had an average of 2.5 cognitive risk-factors, compared with an average of less than one risk factor for participants without the symptoms.These risk-factors included diabetes and hypertension, which can increase the risk of stroke, mild cognitive impairment and vascular dementia; and a history of Attention deficit hyperactivity disorder, which may make the brain more vulnerable to executive functioning issues. Other risk factors included anxiety, depression, a history ofA heavy alcohol or repeated stimulant use, and learning disabilities.