Reasoning and Problem-Solving Hit Worst
Of the 81,337 people who completed the full extended questionnaire, 12,689 reported catching COVID-19. Among this group, 3,559 had respiratory symptoms but were able to stay at home, 192 were admitted to hospital, and 44 were put on ventilators. This large and socioeconomically diverse population provided a great deal of information about themselves which allowed for researchers to analyze many variables that affect cognitive health. After controlling for all these factors, the researchers found that those who contracted the virus cognitively under-performed those who didn't. Some abilities were not affected. These included emotional discrimination (recognition of faces that were expressing the same emotion) and working memory (remembering where a sequence of squares appears on the screen). However, executive tasks that required skills in reasoning (such as deciding if relationships between words were similar) and problem solving (working out how many moves it would take to go from one arrangement to another) showed the greatest deficit.Severity of Respiratory Symptoms is Key
In addition, the researchers found that the more severe the respiratory symptoms, the worse the cognitive performance. Those hospitalized and put on a mechanical ventilator saw cognitive deficits that were much the same as the average cognitive decline seen in ten years of aging; a decline that's equivalent to a seven-point loss in IQ. To make sure these deficits really were linked to the virus, the research team separated out those with a confirmed positive test from those who simply reported that they caught the infection. They also checked that people didn't have pre-existing conditions or on-going symptoms of COVID-19, or that the more severely affected were less cognitively able before they were ill. Even after taking all these additional factors into account, the findings still held up. However, because of the way the study was designed it’s not possible to say for sure whether COVID-19 causes cognitive decline, only that it's linked to it.Neurological Problems Occur During Pandemics
Dr. Adam Hampshire, first author on the study, said, “Our study adds to an increasing body of research that is looking at different aspects of how COVID-19 might be impacting the brain and brain function. “This research is all converging to indicate that there are some important effects of COVID-19 on the brain that need further investigation. "Going forward it would be valuable to bring together brain imaging and cognitive tests with other information on mental health and everyday function, ideally in studies that track people's trajectories for months or even years. To really know what the long-term effects are for people will require people to be followed up over time.” The findings of this study should not come as a surprise. Research has linked other viruses, such as the flu, to neurological damage. A review by researchers from Canada in 2012 noted that “influenza-associated neurological complications have become increasingly recognized [and] a surge in the incidence of severe [neurological] diseases in young and otherwise healthy adults is noted during pandemics.”- https://www.psypost.org/2021/07/large-study-finds-covid-19-is-linked-to-a-substantial-drop-in- intelligence-61577
- https://www.kcl.ac.uk/news/problems-in-thinking-and-attention-linked-to-covid-19-infection
- https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00324-2/fulltext
- https://link.springer.com/article/10.1007/s12028-012-9796-8
