Brain fog from mild COVID linked to lingering inflammation
An after-effect of COVID-19 (COVID), brain fog has been reported in over 65% of patients at a post COVID clinic in New York – suspected due to brain inflammation, as well as the presence of unexpected antibodies found in an activated immune system. Researchers from the University of California, San Francisco (UCSF), further confirm this abnormality in a new study on cerebrospinal fluid (CSF) biomarkers in long COVID patients experiencing brain fog.
In a small cohort of subjects ten months past a mild case of COVID-19, thirteen had complained of persistent signs of brain fog, while the remaining four served as controls with no post-COVID cognitive problems.
Digging deeper, the researchers found that 77% (10 out of 13) of those experiencing persistent brain fog showed a number of CSF abnormalities, including elevated levels of proteins indicating the presence of neuroinflammation and unusual volumes of immune antibodies.
“It’s possible that the immune system, stimulated by the virus, may be functioning in an unintended pathological way,” said Dr. Joanna Hellmuth, of the UCSF Memory and Aging Center. “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.”
Interestingly, nearly half of those who reported persistent cognitive problems following a COVID infection indicated a delayed onset of their cognitive symptoms. This reported brain fog did not arise until a month after the first COVID symptom in about 43% of subjects while 29% reported their cognitive problems did not appear until two months after initial symptoms.
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 ADHD (attention-deficit hyperactivity disorder), which may make the brain more vulnerable to executive functioning issues.
Other risk factors included anxiety, depression, a history of heavy alcohol or repeated stimulant use, and learning disabilities.
Nevertheless, it is plausible to assume infection with SARS-CoV-2 can lead to lingering cognitive problems, Dr. Hellmuth said. These long COVID symptoms can be seen in patients experiencing a mild initial illness, “If people tell us they have new thinking and memory issues, I think we should believe them rather than require that they meet certain severity criteria.”
Read: Gene determines the risk of developing severe COVID-19
