COVID may impact your cognitive abilities a year or more after infection, study finds

A new study hints that COVID-19 can impact cognitive performances up to more than a year after having contracted the virus. - Copyright Canva

By Oceane Duboust

Published on 01/03/2024 - 12:58

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A new study found that COVID-19 is linked to persistent cognitive deficits, emphasising the need for ongoing research.

A new study suggests that COVID-19 can impact cognitive function a year or more after people have contracted the virus.

The study enrolled more than 140,000 participants and assessed the cognitive and memory abilities of individuals who had recovered from COVID-19 compared to those who had not been infected.

Study participants were tasked with completing an online cognitive evaluation using a platform called Cognitron. The tasks were designed to identify nuanced changes to cognition such as memory, reasoning, attention, and impulsivity.

“The potential long-term effects of COVID-19 on cognitive function have been a concern for the public, healthcare professionals, and policymakers, but until now it has been difficult to objectively measure them in a large population sample,” Adam Hampshire, a professor at Imperial College London and one of the study’s authors said in a statement.

“By using our online platform to measure multiple aspects of cognition and memory at large scale, we were able to detect small but measurable deficits in cognitive task performance. We also found that people were likely affected in different ways depending on factors such as illness duration, virus variant and hospitalisation,” he added.

The findings were published in the New England Journal of Medicine.

Memory is among the cognitive capacities impacted

The study detected small but persistent deficits in cognitive and memory tasks among those who had recovered from COVID-19 compared to those who had not been infected.

The cognitive deficit was roughly equivalent to 3 points on the IQ (intelligence quotient) scale.

Notably, individuals who experienced persistent symptoms or “long COVID” had more cognitive problems representing a loss of around 6 IQ points. Those hospitalised in intensive care had cognitive deficits of around 9 IQ points.

The study showed that COVID-19 appeared to impact memory in particular, such as recalling images of objects observed a few minutes earlier.

This suggests that the difficulties were linked to forming new memories.

Small deficits were also observed in tasks assessing executive and reasoning abilities, such as spatial planning and verbal reasoning.

The findings also suggest that cognitive effects were less pronounced in those infected with COVID-19 during the period when Omicron emerged as the main variant.

“It is reassuring that people with persistent symptoms after COVID-19, that had resolved, may expect to experience some improvement in their cognitive functions to similar levels as those who experienced short illness,” said Paul Elliott, a professor at Imperial College London and senior author of the study.

He underlined the importance of continued monitoring of “the long-term clinical and cognitive consequences”.

“Cognitive deficits in people who had COVID-19 is an important public health problem. But the magnitude of cognitive problems experienced by patients remained largely unknown,” said Maxime Taquet from the University of Oxford who did not take part in the study.

“By using an innovative cognitive test which has also been completed by people who did not have COVID-19, this important and well-conducted study provides the first accurate quantification of the scale of cognitive deficits in people who had COVID-19,” he added.

Long COVID still being researched

Research is still ongoing to understand the long-term consequences that can follow a COVID-19 infection.

The condition called “long COVID” encompasses a wide range of symptoms that persist for weeks or even months after the initial coronavirus infection.

These symptoms can vary greatly between individuals, but fatigue, shortness of breath, and difficulty concentrating are commonly reported.

One of the most common and debilitating symptoms of long COVID is brain fog, characterised by difficulty concentrating, remembering, and processing information.

The research conducted by Imperial College London is part of one of the world’s largest and longest-running COVID studies: REACT for Real-Time Assessment of Community Transmission.

It was launched in April 2020 and monitors the data of 2.7 million adults in England “to understand more about the natural history of COVID-19,” the disease outcomes, as well as the effectiveness of vaccination.

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