Two new studies are reporting on an ongoing long COVID research project investigating the persistent effects of COVID-19 on cognition in the months after acute disease. The University of Cambridge-led research found many long COVID patients are experiencing significant and measurable memory or concentration impairments even after mild illness.

"Long COVID has received very little attention politically or medically," said Lucy Cheke, senior author on the new studies. "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 new findings come from an ongoing project called The COVID and Cognition Study (COVCOG). The study recruited nearly 200 COVID-19 patients across late 2020/early 2021 and around the same amount of demographically matched uninfected controls. The goal was to "map the terrain" of cognition in post-acute COVID-19.

Around two-thirds of the COVID-19 cohort experienced symptoms of long COVID, defined as a symptom lasting longer than 12 weeks beyond initial date of diagnosis. Among those experiencing long COVID the new research found 78 percent had difficulty concentrating, 69 percent suffered brain fog, 68 percent reported forgetfulness and around 40 percent displayed a condition known as semantic disfluency (saying or typing the wrong word).

The study also found those subjects with long COVID experienced significant disruptions to their daily lives. More than half the long COVID cohort were unable to work for extended periods of time and one-third lost their job due to their illness.

Perhaps most strikingly, the research found half the long COVID cohort reported problems getting doctors to take their persistent symptoms seriously. Muzaffer Kaser, a researcher working on the COVCOG project, says these findings affirm something real and measurable is happening to these patients.

"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," said Kaser. "The effects are measurable – something concerning is happening. Memory difficulties can significantly affect people’s daily lives, including the ability to do their jobs properly."

As with prior long COVID studies, the new findings indicate the severity of a patient’s initial infection can help predict the likelihood of long COVID symptoms. Few subjects in the study were so acutely ill they needed to be hospitalized, however, those reporting more severe acute disease were more likely to report persistent cognitive problems.

Plus, those with the broadest symptoms during their acute disease were most likely to experience lingering cognitive problems. In other words, those experiencing combinations of neurological, gastrointestinal and cardiopulmonary symptoms early on were at greater risk of cognitive problems several months down the line.

The new research concludes there are "objective cognitive differences" between those who have and haven’t been infected with COVID-19. But it is still unclear exactly what is specifically causing these persistent cognitive symptoms. The researchers hypothesize lingering systemic inflammation as a plausible causal mechanism but suggest more targeted research will need to investigate this proposal.

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

The COVCOG study is ongoing, but Kaser said these new findings should help both patients and doctors better understand and identify cases of long COVID. He also pointed to a number of long COVID clinics now opening up across the UK to help patients manage this new chronic condition.

"It’s important that people seek help if they’re concerned about any persistent symptoms after COVID infection," said Kaser. "COVID can affect multiple systems and further assessment is available in long COVID clinics across the UK, following a GP referral."

The two new studies were published in the journal Frontiers in Aging Neuroscience (1, 2).

Source: University of Cambridge