A group of researchers with King’s College London studied the impact of COVID-19 on brain function through a series of cognitive tests on people who had COVID-19 and recovered quickly or had COVID-19 and are still dealing with symptoms years later.
The study, published in the journal eClinicalMedicine within The Lancet on July 21, recruited more than 8,000 participants through a phone app, COVID Symptom Study Biobank, run by the National Health Service in the United Kingdom.
Study participants enrolled in March 2020 and were encouraged to join before they had any symptoms of COVID-19.
Over the course of a year, some participants never contracted COVID-19, some caught the coronavirus but only had symptoms for a few days, and others became sick and remained sick for more than 12 weeks, meeting the qualification of “long COVID,” the study said.
In 2021, the study participants went through the first round of cognitive testing, then went through another round of tests the next year, according to the study.
“In both rounds of assessment, participants undertook 12 cognitive tasks assessing different cognitive domains, including working memory, attention, reasoning and motor control,” the study said.
From those tests, the researchers looked at the accuracy of the answers, the participants’ reaction time for answering and completing the tests, and their variation in reaction time between different types of tests, the study said.
When they compared the results of the tests between COVID-19 patients who recovered quickly versus those who had long COVID, they found a staggering difference.
Long COVID patients who were still experiencing symptoms showed mental deficits equivalent to “an increase in age of approximately 10 years,” the study said.
The patients also exhibited signs of psychological distress that couldn’t be explained by fatigue or receiving less schooling, according to the study.
“Our findings suggest that, for people who were living with long-term symptoms after having COVID-19, the effects of the corona virus on mental processes such as the ability to recall words and shapes are still detectable at an average of almost two years since their initial infection,” study author Nathan Cheetham told EuroNews.
The study also noted that participants who showed cognitive decline in the first round of testing did not show any recovery when they were tested again nine months later.
According to data from the Kaiser Family Foundation (KFF), 28 percent of Americans who were infected with COVID-19 reported having lingering symptoms that eventually went away or still persist as of January this year.
Of those who report still having COVID-19 symptoms even years after becoming infected, 79 percent reported having limits on their day-to-day activities, KFF reported.
The study suggests this may, in part, be because of changes in their brain function.
Cheetham told EuroNews the study highlights the need to monitor the brain function of those dealing with long COVID “to see how their cognitive symptoms continue to develop and provide support towards recovery.”