The COVID-19 pandemic has left indelible marks on various aspects of daily life; perhaps you yourself have detected after overcoming an infection that you have had memory loss or have felt more clumsy when performing some tasks. Has the coronavirus infection affected our cognitive and memory abilities? Several investigations have investigated these questions, and a recent study published on February 29 in the New England Journal of Medicine and led by researchers at Imperial College London sheds light on this question, offering evidence of small but lasting impacts on cognitive and memory task performance in people who had recovered from COVID-19 compared to those who had not had COVID. -19.
Conducted in a large community sample, the REACT Long COVID study enrolled more than 140,000 participants to assess their cognitive functions using an online assessment platform. The findings suggest mild deficits in cognitive and memory tasks, even a year or more after infection, with more marked effects in those who were hospitalized, had long-lasting symptoms, or were infected with earlier variants of the virus.
Participants in the study were asked to take an innovative online cognitive assessment on the Cognitron platform, comprising tasks that can detect subtle changes in different aspects of their brain function, such as memory, reasoning, executive function, attention and impulsivity. The large scale of the study and the sensitivity of the computerized tests allowed us to examine in great detail the factors explaining post-COVID cognitive deficits while controlling for population variables such as age, demographics, and pre-existing medical conditions.
The study revealed small deficits that were still detectable a year or more after infection, even in people who had a short duration of illness. They were larger for people who had symptoms lasting 12 weeks or longer (consistent with long COVID), those who had been in the hospital for their illness, or those who were infected with an early variant of the SARS-CoV-2 virus. .
However, people who had longer-lasting symptoms that had resolved by the time they took the cognitive assessment showed small deficits that were similar in size to people who had a shorter illness duration.
Cognitive deficits were greater in people who were hospitalized, had long-lasting ongoing symptoms, or were infected with earlier variants of the virus.
The results showed that COVID-19 was associated with deficits in multiple areas of cognition, especially memory, such as the ability to remember images of objects seen a few minutes earlier. Researchers believe this may be due to problems forming new memories rather than accelerated forgetting.
People also showed small deficits on some tasks that test executive and reasoning skills, such as those requiring spatial planning or verbal reasoning.
Professor Adam Hampshire from the Department of Brain Sciences at Imperial College London, co-author of the study, highlights the importance of these results: “The long-term effects of COVID-19 on cognitive function have worried the public, healthcare professionals and health and political leaders. “Our study provides objective measures of these effects in a large population sample.” The expert points out that “We also found that people were probably affected in different ways depending on factors such as duration of illness, virus variant, and hospitalization.”
Despite the challenges COVID-19 poses to cognition, the study offers a glimmer of hope. Individuals with persistent symptoms that eventually resolved showed improvements in their cognitive functions, approaching the levels of those with short-term illnesses. Professor Paul Elliott, lead author of this work and director of the REACT programme, from the School of Public Health Sciences at Imperial College London, said: “It is reassuring that people with persistent symptoms after COVID-19, who have resolved , can expect to experience some improvement in their cognitive functions to levels similar to those who experienced a brief illness.”
Furthermore, the cognitive impact of the coronavirus appears to have diminished since the early stages of the pandemic, particularly among those infected during the predominance of the Omicron variant. The study highlights the need to continue monitoring the clinical and cognitive consequences of the COVID-19 pandemic, given the large number of people affected, highlighting the need for support and rehabilitation strategies for those affected. This study therefore represents a crucial step towards understanding and managing the cognitive consequences of COVID-19, highlighting both the resilience and vulnerability of our cognitive system in the face of this global disease.
