Authored by Megan Redshaw via The Epoch Times
A new study found that COVID-19 infection can cause cognitive deficits that persist for over a year and lower IQ scores in severe cases. Those with persistent symptoms that resolved had small cognitive deficits similar to those with a shorter illness duration.
In a large-scale observational study published on Feb. 29 in the New England Journal of Medicine (NEJM), researchers invited 800,000 people with varying levels of COVID-19 exposure and duration to take an online cognitive assessment and follow-up survey. Cognitive difficulties have been implicated in numerous syndromes following COVID-19, including long COVID, suggesting infection may have lasting effects on the mental processes of the brain.
The study’s authors hypothesized there would be measurable cognitive deficits after COVID-19 that would scale with the severity and duration of the illness. They also speculated that objective impairments in executive and memory function, especially poor memory and brain fog, would be observable in those with persistent symptoms.
Using an assessment tool for cognitive function, researchers estimated global cognitive scores among participants with a history of previous SARS-CoV-2 infection who had symptoms for at least 12 weeks—whether resolved or not—and among a control group of uninfected participants. While cognitive and memory deficits were small for people with mild infection who recovered from COVID-19 quickly, impairments were more pronounced in those with severe disease. Greater Impairment With More Severe Disease
Of 112,964 participants who completed the survey, those who recovered from COVID-19 with symptoms that resolved in less than four weeks or by 12 weeks post-infection had similar small deficits in global cognition compared with those who had never had COVID-19.
Participants who had mild COVID-19 with resolved symptoms experienced a 3-point drop in IQ compared to uninfected participants. Those with unresolved persistent symptoms had a 6-point loss in IQ, and those with COVID-19 admitted to the intensive care unit experienced a 9-point loss in IQ. Reinfection with SARS-CoV-2 caused an additional loss in IQ of nearly 2 points compared to those who were not reinfected. An IQ, or intelligence quotient, is a number used to represent the relative intelligence of an individual.
According to the study, memory, reasoning, and executive function tasks were the strongest indicators of impaired cognitive function, and these scores correlated with brain fog symptoms reported by participants. More significant deficits were seen in those with unresolved persistent symptoms and those infected with earlier variants of the SARS-CoV-2 virus compared with those who never had COVID-19. Additionally, study participants who were hospitalized had greater deficits in cognitive function compared to those who were not hospitalized. B