King’s College London researchers investigated how COVID-19 impacted cognitive function in individuals through two rounds of online testing. The tests, one in 2021 and the next in 2022, had tasks that measured participants’ memory, attention, reasoning, processing speed, and motor control. Over 3,000 individuals shared their data for this study.

“We used sensitive tests to measure speed and accuracy across a range of brain challenges. This study shows that some individuals have measurable changes in these tests after COVID-19 going on for nearly two years. The fact remains that two years on from their first infection, some people don’t feel fully recovered and their lives continue to be impacted by the long-term effects of the coronavirus. We need more work to understand why this is the case and what can be done to help.” – Professor Claire Steves, of King’s College London’s Department of Ageing and Health

The test scores that COVID-19 influenced the most were for those who said they’d experienced symptoms related to the virus for 12+ weeks. Experts remark that COVID-19 had a negative effect on test accuracy comparable to a 10-year increase in age in these participants, with no notable improvements between both online testing sessions. The researchers then split the participants into groups based on how recovered from the virus they’d felt. Turns out, those who felt fully recovered after experiencing the infection performed similarly to those who never had COVID-19 at all. Participants who experienced ongoing symptoms, on the other hand, performed worse on task accuracy on average.

Dr Nathan Cheetham, lead author, concludes: “Our findings suggest that, for people who were living with long-term symptoms after having COVID-19, the effects of the coronavirus 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… This study shows the need to monitor those people whose brain function is most affected by COVID-19, to see how their cognitive symptoms continue to develop and provide support towards recovery.”

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Journal Reference:

  1. Nathan J. Cheetham, Rose Penfold, Valentina Giunchiglia, Vicky Bowyer, Carole H. Sudre, Liane S. Canas, Jie Deng, Benjamin Murray, Eric Kerfoot, Michela Antonelli, Khaled Rjoob, Erika Molteni, Marc F. Österdahl, Nicholas R. Harvey, William R. Trender, Michael H. Malim, Katie J. Doores, Peter J. Hellyer, Marc Modat, Alexander Hammers, Sebastien Ourselin, Emma L. Duncan, Adam Hampshire, Claire J. Steves. The effects of COVID-19 on cognitive performance in a community-based cohort: a COVID symptom study biobank prospective cohort study. eClinicalMedicine, 2023; 102086 DOI: 10.1016/j.eclinm.2023.102086
  2. King’s College London. “Some people’s brain function still affected by Long COVID years after infection.” ScienceDaily. ScienceDaily, 21 July 2023. <>.