Study participants with longer-lasting COVID symptoms showed the most substantial decline in cognitive function.

“Long COVID,” or persistent symptoms after an initial COVID-19 infection, can lead to cognitive difficulties such as memory loss and brain fog. Now, a study finds that these symptoms are comparable to brain aging by ten years.

The researchers tested the mental speed and accuracy of participants with and without COVID-19 and found that the cognitive decline was most severe for those who experienced COVID symptoms for more than 12 weeks, according to a study published in The Lancet’s journal eClinicalMedicine [1].

“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,” Claire Steves, a co-author of the study who researches aging and mental health at King’s College London, says in a statement [2].

In the early days of the COVID-19 pandemic, scientists raced to understand symptoms such as depression, major fatigue, brain fog and even dementia. In 2020, another team of researchers examined the brains of people who had died from COVID-19 and found the blood vessels had been severely damaged [3].

The new study tested memory, processing speed, attention, motor control and other skills of more than 3,000 participants to better understand long COVID’s effects on the brain. A little over half of the participants had previously tested positive for COVID-19, and all were recruited through the COVID Symptom Study Biobank smartphone app.

In their paper, researchers found the cognitive impairment associated with long COVID in 2021 comparable to mild or moderate psychological distress or ten years of aging. During the second round of testing, which took place in 2022, no significant improvements were observed. The cognitive decline of some participants lasted nearly two years after infection.

Is there a positive takeaway? A person’s cognitive function seemed to recover once COVID symptoms disappeared regardless of whether they had persisted for three months or one week.

About 15 percent of US adults have experienced long COVID, according to the Household Pulse Survey by the National Center for Health Statistics [4].

More research is needed into how long COVID victims can be aided in their recovery process, especially those who have lived with the symptoms for years [5].

[1] https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(23)00263-8/fulltext
[2] https://www.kcl.ac.uk/people/claire-steves
[3] https://www.nih.gov/news-events/news-releases/nih-study-uncovers-blood-vessel-damage-inflammation-covid-19-patients-brains-no-infection
[4] https://www.cdc.gov/nchs/covid19/pulse/long-covid.htm
[5] https://www.medscape.co.uk/viewarticle/long-covid-brain-fog-comparable-ageing-10-years-2023a1000gqt