Cognitive Problems Persist in Patients with Long Covid

By Pat Anson, PNN Editor

About 70% of people with long covid have concentration and memory problems several months after their initial infection with Covid-19, according to new research at the University of Cambridge. The severity of the symptoms appears to be linked to the level of fatigue and headache people experienced during their initial illness.

Long covid is a poorly understood disorder characterized by body pain, fatigue, cognitive impairment and difficulty sleeping. About a third of people infected with coronavirus develop symptoms that can last for many months.   

In their study of 181 long covid patients, published in the journal Frontiers in Aging Neuroscience, researchers found that 78% reported difficulty concentrating, 69% had brain fog, 68% experienced forgetfulness, and 60% had trouble finding the right word to use in speech. They also performed poorly in cognitive tests, with significantly lower ability to remember words and pictures.

“This is important evidence that when people say they’re having cognitive difficulties post-COVID, these are not necessarily the result of anxiety or depression. The effects are measurable - something concerning is happening,” said co-author Muzaffer Kaser, PhD, a psychiatrist and researcher at the University of Cambridge. “Memory difficulties can significantly affect people’s daily lives, including the ability to do their jobs properly.”

The findings are further evidence that Covid-19 will have a lasting impact around the world, long after the pandemic subsides. Cambridge researchers say their study supports other findings that suggest society will face a “long tail” of workforce illness due to long covid.

“Long covid has received very little attention politically or medically. It urgently needs to be taken more seriously, and cognitive issues are an important part of this. When politicians talk about ‘Living with COVID’ – that is, unmitigated infection, this is something they ignore. The impact on the working population could be huge,” said senior author Lucy Cheke, PhD, a psychologist and lecturer at Cambridge.

To help understand the cause of the cognitive problems, Cheke and her colleagues investigated other symptoms that might be linked. They found that people who experienced fatigue and neurological symptoms, such as dizziness and headache, during their initial illness were more likely to have cognitive issues later on.

Participants were assigned to carry out multiple tasks to assess their decision-making and memory. These included remembering words on a list, and remembering which two images appeared together. The results revealed a consistent pattern of memory problems in people with long covid -- problems that were more pronounced in those whose initial neurological symptoms were more severe.

“People think that long covid is ‘just’ fatigue or a cough, but cognitive issues are the second most common symptom - and our data suggest this is because there is a significant impact on the ability to remember. There is growing evidence that COVID-19 impacts the brain, and our findings reflect that,” said Cheke.

Study participants were recruited between October 2020 and March 2021, when the Alpha variant and the original form of SARS-CoV-2 were still the dominant forms of the virus.

Very few of the patients had symptoms severe enough to be admitted to a hospital. But even among those who were not hospitalized, researchers found that people with severe initial symptoms were more likely to develop long covid than those with mild symptoms. They also found that people over 30 were more likely to have severe ongoing symptoms than younger ones.

“Infection with the virus that causes COVID-19 can lead to inflammation in the body, and this inflammation can affect behaviour and cognitive performance in ways we still don’t fully understand, but we think are related to an early excessive immune response,” said Kaser.

As is often the case with chronic illness, half of the patients with long covid reported difficulty getting medical providers to take their symptoms seriously, perhaps because cognitive symptoms do not get the same attention as respiratory problems.

The Cambridge study currently has no data on long covid associated with the Delta or Omicron variants of coronavirus, although new patients are being recruited to fill that void. The researchers say more studies are needed to understand the complex effects of Covid on the brain, cognition and mental health.

One way to reduce your risk of long covid is to get vaccinated. A UK study last year found that people who received the Moderna, Pfizer or AstraZeneca vaccines had significantly lower risk of an infection that turns into long covid.