Study Reveals Long Covid’s Impact on Cognitive Abilities
A groundbreaking study conducted in the summer of 2022 has shed light on the long-term effects of Covid-19 on cognitive and memory abilities. The research, which involved over 140,000 participants, suggests that individuals experiencing long Covid may suffer from measurable memory and cognitive deficits equivalent to a difference of about six IQ points. These deficits can persist for a year or more after infection, highlighting the profound impact of the virus on the brain.
The study, led by Prof Adam Hampshire, a cognitive neuroscientist at Imperial College London, aimed to understand the phenomenon commonly referred to as “brain fog.” While brain fog has been extensively reported as a symptom of long Covid, its objective impact had remained unclear. However, this study’s findings demonstrate that brain fog is indeed associated with quantifiable cognitive deficits, making it a significant discovery in the field.
In the United Kingdom alone, it was estimated that around 2 million people were experiencing self-reported long Covid symptoms. The study’s participants were recruited from the React cohort, one of the world’s largest and most comprehensive Covid surveillance studies. The online cognitive tests administered to the participants assessed various aspects of brain function, including memory, attention, reasoning, and executive function.
The analysis revealed that even individuals who had recovered from Covid-19 and no longer exhibited symptoms still displayed detectable cognitive deficits a year or more after infection. The difference in test scores between those who had been infected and those who had not was equivalent to approximately three IQ points. While this change may not be noticeable on an individual level, some individuals may experience more pronounced effects.
However, the study found that those with unresolved symptoms lasting more than 12 weeks had a larger deficit, equivalent to six IQ points. This finding raises concerns about the ability of these individuals to work and function normally. Dr Maxime Taquet, a psychiatrist and researcher at the University of Oxford, emphasized the worrisome impact of these deficits, particularly considering the scale of the pandemic and the number of people affected.
On a more positive note, individuals who had longer-lasting symptoms that eventually resolved showed comparable deficits to those who had experienced mild, short-duration illness. This suggests that cognitive functions may improve over time for those with persistent symptoms after Covid-19.
The study also revealed that individuals with unresolved symptoms lasting 12 weeks or more, consistent with long Covid, and those who had been hospitalized for their illness exhibited more noticeable deficits across a broader range of cognitive functions. Additionally, the differences were more significant for those infected with early variants of the virus. However, it remains unclear whether this is due to the introduction of vaccines and better treatment as the pandemic unfolded.
The findings of this study have been published in the prestigious New England Journal of Medicine, providing valuable insights into the long-term effects of Covid-19 on cognitive abilities. The research highlights the need for further investigation into the impact of the virus on the brain and underscores the importance of addressing the cognitive deficits experienced by individuals with long Covid. By understanding these effects, healthcare professionals can develop targeted interventions to support those affected and mitigate the long-term consequences of the virus on cognitive function.
