According to a preliminary study, COVID-19 may cause the brains of some people to age by about 10 years compared to those who did not have the disease.
Over 84,000 people in the UK who reported recovering from a suspected or confirmed case of COVID-19 completed a questionnaire measuring their thinking abilities. The paper was submitted to the preprint server medRxiv, which means that it did not undergo the rigorous peer review process required for publication in a scientific journal, so the results should be interpreted with caution.
The participants underwent tests to measure their problem-solving ability, spatial memory, attention and processing of emotions.
Respondents indicated whether they had or suspected they had COVID-19. They were asked how long their symptoms lasted, as well as the severity of the disease and whether they had any underlying medical conditions. Their results were compared with those of the healthy participants who served as a control group.
Participants who stated that they had COVID-19 scored worse on cognitive tests than the control group.
The association was particularly strong in people with severe COVID-19, but was also found in people with a mild form of the disease. A mild case of COVID-19 was defined in the study as someone who had no breathing problems.
The team revealed “particularly pronounced problems” with the so-called higher cognition. The problems were related to the attention and thinking of the participants, especially verbal thinking, study co-author Adam Hampshire from the Brain Science Department at Imperial College London told Tekk.tv.
Patients aged 20 to 70 years who were hospitalized and connected to a ventilator to support their breathing dropped their thinking skills to the level of a person 10 years older on average.
Hampshire told Tekk.tv that the only significant predictors of cognitive problems were the severity of the patient’s breathing symptoms and a positive test. No other variables, such as whether a person has a pre-existing condition, were responsible for the problems observed by the team, he said.
The team said that their data indicated that “there are chronic cognitive consequences of COVID-19,” and that their work is amid growing evidence from separate studies that COVID-19 patients may experience neurological problems due to complications such as stroke, immune system overreactions and inflammation.
“These results should serve to clarify the need for more detailed research that examines the basis of cognitive deficits in people who have survived infection with SARS-COV-2 [coronavirus],” the authors wrote.
Experts who were not involved in the study said the results do not prove that COVID-19 causes thought disorders.
Joanna Wardlaw, Professor of Applied Neuroimaging at the University of Edinburgh, UK, said in a statement that the study was limited because the team had no information about the cognitive function of participants before taking COVID-19. The problems they uncovered may also be short-term in nature, she said.
Derek Hill, Professor of Medical Imaging Sciences at UCL in the UK, said in a statement that the study was “a fascinating but inconclusive research result”. He said the information may not be reliable because the researchers relied on participants reporting their own symptoms, and said only a “tiny fraction” had a positive coronavirus test.
Hill also said that the team had not studied how COVID-19 affects the brain biologically, for example through scans. “It is known that the cognitive decline in Alzheimer’s disease is associated with brain shrinkage, which is detected by MRI scans,” Hill said.
David Strain, senior clinical lecturer at the University of Exeter, UK, said in a statement that the finding that the brains of some people with COVID-19 at around 10 years of age are “much worse” compared to those without the disease than what is seen in other people who have recovered from other viruses.
The team is still recruiting people for its study, which can be completed by clicking here. The results are limited, as only 361 of the 84,000 participants tested positive for the virus. Hampshire said the number reflected the proportion of the British population,