By Michael Le Page, et al.
People hospitalised with covid-19 may lose 10 IQ points, equivalent to the natural cognitive decline that occurs between 50 and 70 years old
Covid-19 can cause lasting cognitive and mental health issues, including brain fog, fatigue and even post-traumatic stress disorder. To better understand the scale of the problem, researchers at the University of Cambridge analysed 46 people who were hospitalised due to the infection between March and July 2020.
The participants underwent cognitive tests on average six months after their initial illness.
These results were compared against those of more than 66,000 people from the general population.
Those hospitalised with covid-19 scored worse on verbal analogical reasoning tests, which assess an individual’s ability to recognise relationships between ideas and think methodically.
They also recorded slower processing speeds. Previous studies suggest glucose is less efficiently used by the part of the brain responsible for attention, complex problem-solving and working memory after covid-19.
Scores and reaction speeds improved over time, however, any recovery was gradual at best, according to the researchers.
This cognitive impairment probably has multiple causes, including inadequate blood supply to the brain, blood vessel blockage and microscopic bleeds caused by SARS-CoV-2 virus, as well as damage triggered by an overactive immune system, they added.
“Around 40,000 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,” Adam Hampshire at Imperial College London said in a statement.
“This means there is a large number of people out there still experiencing problems with cognition many months later.”