Long Covid: Impacts on Memory and Cognitive Abilities
Researchers have found that individuals experiencing long Covid may face measurable memory and cognitive deficits, equivalent to a difference of regarding six IQ points. A study conducted on more than 140,000 people in the summer of 2022 suggests that the effects of Covid-19 on cognitive and memory abilities can last for a year or more following infection. The study also reveals that individuals with unresolved symptoms lasting over 12 weeks exhibit more significant deficits in tasks involving memory, reasoning, and executive function. This highlights the quantifiable impact of what is commonly referred to as “brain fog.”
The cognitive neuroscientist Prof Adam Hampshire, from Imperial College London, and the first author of the study, explains that brain fog has been a well-reported symptom, but its objective measurement has been unclear until now. Hampshire states, “What our study shows is that brain fog can correlate with objectively measurable deficits. That is quite an important finding.”
Long Covid is a phenomenon affecting a substantial number of people. In the UK alone, an estimated 2 million individuals reported symptoms of long Covid, according to the Office for National Statistics. Furthermore, a previous analysis by Imperial College London found that tens of thousands of people in England experienced symptoms persisting for a year or more following infection.
The study recruited participants from the React cohort, one of the world’s largest and most comprehensive Covid surveillance studies. Between August and September 2022, over 140,000 individuals underwent online cognitive tests to evaluate memory, attention, reasoning, and other aspects of brain function. Of the cohort, 3.5% reported symptoms persisting beyond 12 weeks, with a significant portion still experiencing symptoms at the time of assessment.
The analysis uncovered small, yet detectable, deficits in individuals who had been infected with Covid-19 but no longer displayed symptoms. These deficits were equivalent to approximately three IQ points. While this magnitude of change may not be noticeable to an individual, some participants did exhibit more pronounced effects. Notably, those with unresolved symptoms lasting more than 12 weeks showcased a larger deficit, equivalent to six IQ points.
Dr Maxime Taquet, a psychiatrist and researcher from the University of Oxford, expresses concern over the impact of these deficits on individuals’ ability to work and function. He states, “Even if cognitive deficits following Covid-19 are of small magnitude on average, a substantial minority of people have more significant deficits which are likely to affect their ability to work and function. Given the scale of the pandemic and the number of people affected, this is particularly worrisome.”
However, there is some encouraging news. The study found that individuals with longer-lasting symptoms that had resolved experienced comparable deficits to those who had only encountered mild, short-duration illness. This suggests that cognitive functions may improve to similar levels as individuals who experienced a shorter illness.
The analysis also identified more substantial deficits among those with unresolved symptoms lasting 12 weeks or more and those who had been hospitalized for their illness. These deficits extended to a wider range of cognitive functions. Variants of the virus, particularly the early ones, were also linked to bigger differences in test scores. However, it remains uncertain whether this is due to the introduction of vaccines and improved treatments as the pandemic progressed.
The study’s findings, published in the New England Journal of Medicine, shed light on the enduring impacts of Covid-19 on cognitive abilities and memory. Understanding these long-term effects will be crucial in providing support and care to those experiencing long Covid.
Analyzing the Implications
The study’s revelations on the cognitive and memory deficits resulting from long Covid have significant implications for individuals, society, and healthcare systems globally. As the pandemic continues, it becomes increasingly important to address the long-term consequences of Covid-19 on mental and cognitive well-being.
The potential long-term impacts on individuals’ ability to work and function highlight the necessity for comprehensive support and rehabilitation. Employers and policymakers must take these findings into account
