A new study is quantifying the harms of long COVID, showing that people with lingering symptoms of it can have cognitive deficits equal to losing intelligence quotient, or IQ, points.
Researchers published a report on Feb. 29 in the New England Journal of Medicine detailing their findings. The team evaluated data from 112,964 adults in England who took an online test of their cognitive function. The test wasn’t an IQ test; instead it measured eight tasks similar to IQ measures.
People who recovered from COVID-19 and saw symptoms resolve in less than four weeks or at least 12 weeks had test scores equal to three fewer IQ points compared to those who were uninfected. (About 41% of the people never had COVID-19 in the cohort.) People with long COVID (when symptoms persist after 12 weeks) had a six-point drop in cognitive scores. People who needed hospital care for COVID-19 had cognitive deficits similar to losing nine IQ points.
Memory, reasoning and executive function were linked to the highest deficits in cognitive ability, the study found. The authors said that performance on those tasks differed according to illness duration and hospitalization. Scores on those specific functions were also weakly linked with people who had unresolved and resolved symptoms but had recent poor memory or brain fog. The scores weren’t linked in those free from COVID-19.
“Participants with resolved persistent symptoms after COVID-19 had objectively measured cognitive function similar to that in participants with shorter-duration symptoms, although short-duration COVID-19 was still associated with small cognitive deficits after recovery,” the authors wrote.One issue the authors found that aligned with other research is that people who had the original SARS-CoV-2 strain and the Alpha strain of the virus were worse off compared to people who were infected by the Delta and Omicron variants. Previous research has found that those with more severe infections were more likely to have long-term problems.
