And innovative experiment carried out in the United Kingdom has revealed that infection by SARS-CoV-2the coronavirus that causes COVID-19, produces persistent effects on cognition and memory. Participants who had a mild infection showed evidence of persistent cognitive and memory changes at least a year after contracting COVID, compared with uninfected control group members. The results were published last Saturday in the journal “eClinicalMedicine”from the prestigious group “The Lancet”.
The most novel aspect of this study (Changes in memory and cognition during the SARS-CoV-2 human challenge study), carried out between March 2021 and July 2022, is that the wild-type SARS-CoV-2 coronavirus – the one that started the pandemic in Wuhan, China – was inoculated volunteers. Were 34 young people (18–30 years; mean age: 23 years), healthy, seronegative subjects (no antibodies from previous infection or vaccination) under controlled conditions. Eighteen participants became infected, while 16 did not develop the infection. The viral load disappeared in all infected subjects after approximately thirty days. None were hospitalized.
The volunteers completed Daily physiological measurements and computer-based cognitive tasks during quarantine and follow-up at 30, 90, 180, 270 and 360 days. None of the volunteers – neither the 18 infected nor the 16 uninfected – reported any subjective cognitive symptoms; that is, they did not perceive any decline in their cognitive abilities. However, the tests they underwent did reveal a deficit in their cognitive abilities.
Among other problems, tests showed, after 6 months, that those infected presented Decreased working memory, reaction time, sustained attention, and cognitive flexibility (ability to switch between tasks). The cognitive abilities of the 18 infected remained below those shown by the non-infected throughout the year in which they were monitored, and did not show any improvement over time. This is significant deficits in memory and executive capacity: object manipulation, reaction times, problem solving and spatial planning.
“Future research should examine the biological mechanisms that mediate this relationship, determine how they differ from those seen in other respiratory infections, and explore whether targeted interventions can normalize these executive and memory processes,” they wrote. Adam Hampshire and Gregory Scott, researchers from the Department of Brain Sciences at Imperial College London.
The fact that memory accuracy was reduced is interesting, the authors added, since this process has been closely associated with brain function in the medial temporal lobe of this organ, where signs of accelerated contraction were observed after mild COVID in a study published in the journal “Nature” in 2022.
COVID vaccination is associated with a lower risk of persistent cognitive problems after infection.
Results in 6 months
-Working memory: 9 percent decrease in infected compared to uninfected.
-Reaction time: slower in infected, 7% increase in time taken.
-Cognitive flexibility: 8% decrease in ability to switch between tasks.
-Sustained attention: 5% reduction in accuracy in the infected group.
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