July 30, 2021 – COVID-19 infection may have a significant negative impact on intelligence, according to a new large-scale study from the United Kingdom, with results consistent with reports of “brain fog” in long-distance COVID-19. 19 patients.
Researchers analyzed data from 81,337 people who took the UK IQ test in 2020. Of those, about 13,000 reported that they were infected with COVID-19, and 275 of them completed the test before and after infection.
Those who had previously been infected with the coronavirus found that completing tasks related to reasoning, problem solving and spatial planning became more difficult, the authors said. Researchers controlled for age, education and overall mood.
“These results are consistent with reports of long-term COVID, in which ‘brain fog,’ inattention and difficulty finding the right word are common,” the authors write. “Recovery from COVID-19 infection may be associated with particularly pronounced problems in higher cognitive or ‘executive’ functioning.”
Working memory breadth and emotional processing did not appear to be affected.
The severity of cognitive decline appeared to be related to the severity of the infection. Those who used ventilators while ill showed the most significant effects, the researchers said. On average, they experienced a 7-point drop in IQ.
“The size of the observed deficit was not insignificant,” the authors write. But they say brain imaging is needed before definitive conclusions can be drawn.
“Caution is warranted when inferring the neurobiological or psychological basis of the observed deficits without brain imaging data, although the assessment tasks used here have been shown to map to different networks within the human brain in terms of normal functional activity and connectivity, such as well as structural network damage,” they write.
The researchers speculate that high fever and respiratory problems may be responsible for the cognitive decline. But for most people in the study, these symptoms had long since disappeared – only 4.8 percent reported lingering symptoms, the authors noted.
The study provides insight into one part of the post-COVID picture – a condition that the CDC already tracks closely. According to the agency, long-distance COVID-19 may include a range of lingering symptoms for months after infection, including shortness of breath, headache, joint or muscle pain, dizziness and difficulty thinking or concentrating, also known as “foggy sections of the brain.”