Patients who recover from severe COVID-19 may have lasting cognitive impairment equivalent to 20 years of aging — or the loss of 10 IQ points, a small new study finds.
Study participants included 46 COVID-19 survivors who had received in-hospital care, either on the ward or in an intensive care unit. At an average of six months after recovery, each was given rigorous, detailed computerized cognitive tests.
Overall, participants had slower response times and less accurate responses than a large matched control group from the general population, according to the researchers. Deficits were strongest among those who required mechanical ventilation during their hospital stay, they said.
The cognitive effects of acute COVID-19 illness remain detectable for more than six months, the researchers reported. Signs of improvement were seen in some patients examined at 10 months, but these were not yet statistically significant.
Recovery is at best gradual, said Professor David Menon of the University of Cambridge.
“Cognitive impairment is common to a wide range of neurological disorders, including dementia, and even routine aging,” Menon said. “But the patterns we saw — the cognitive fingerprint of COVID-19 — were distinct from all of these.”
Impaired cognition after severe COVDI-19 is likely the result of a number of factors related to the illness, the researchers noted. These include inadequate oxygen or blood supply to the brain, blockage of blood vessels due to clotting and microscopic bleeds. Damage caused by the body’s inflammatory responses may also be a culprit, they added.
Full findings were published in The Lancet.