The cognitive impairment caused by severe COVID-19 is equivalent to 20 years of aging or the loss of 10 IQ points, according to a small study led by researchers at the University of Cambridge and Imperial College London.
The findings, published April 28 in eClinicalMedicine, are based on an analysis of 46 COVID-19 patients who received critical care at Addenbrooke's Hospital in Cambridge, England, between March 2020 and July 2020. Sixteen of those patients required mechanical ventilation.
Patients underwent comprehensive cognitive assessments that involved measures of memory, attention and reasoning, as well as anxiety, depression and post-traumatic stress disorder. Researchers compared data from their assessments to matched controls.
Overall, severe COVID-19 survivors were less accurate and had slower response times, researchers found. The cognitive effects were strongest among patients who required mechanical ventilation. The research team also found the effects were still detectable six months after acute illness.
They estimated the magnitude of cognitive impairment is similar to the loss experienced between ages 50 and 70 — comparable to 20 years of aging.
"Tens of thousands of people have been through intensive care with COVID-19 in England alone, and many more will have been very sick but not admitted to hospital," said Adam Hampshire, study author and professor in the department of brain sciences at Imperial College London. "This means there are a large number of people out there still experiencing problems with cognition many months later. We urgently need to look at what can be done to help these people."