COVID-19: New data on cognitive impacts found by Western U

A new Western University-led study has shed more light on the impacts of COVID-19, suggesting patients may experience short- and long-term cognitive impairments following infection, which can be similar to those caused by sleep deprivation.

Published on Sept. 6 in the journal Cell Reports Medicine, the study performed in collaboration with the University of Cambridge, Sunnybrook Health Sciences Centre, and the University of Ottawa, was conducted online between June 2020 and February 2021. It looked at the overall Cognitive performance of 478 adult volunteers about three months after they had a confirmed COVID-19 diagnosis.

The study found that post-COVID patients had significant deficits in reasoning, thinking speed, and verbal abilities. Notably, no losses in memory function, commonly referred to as brain fog, were found.

“The pattern of cognitive impairment in these COVID-19 patients resembles that of healthy study participants who are sleep deprived,” Adrian Owen, study co-author and Western University professor, said in a Tuesday news release.

Owen previously conducted a large-scale study in 2017 on the impacts of sleep deprivation, which found that participants’ reasoning and verbal abilities were most impacted by limited sleep.

The cognitive impacts noticed in participants weren’t limited to those with extreme cases, but rather the severity of the impairments was “directly related to the severity of the original infection.”

“The worse the COVID-19 symptoms were for the patient, the worse the cognitive impairments were, as well,” Conon Wild, study co-author, said in the release, noting that significant impairments were also seen in people with mild infections.

The degree of cognitive impairment was also discovered to be unrelated to the interval between COVID-19 infection and the assessment, indicating that impairments may be long-lasting, the study found.

According to Wild, the deficits were not less severe for those who were up to three months post-infection, which shows that these effects might not go away in the short-term.

Participants in the study also displayed significantly higher levels of depression and anxiety, with 30 per cent matching the clinical criteria for either one or both conditions.

But, this wasn’t related to the severity of their infection or the resulting cognitive impairments, but likely “the result of living through the pandemic itself,” Richard Swartz, study co-author, said in the release.

The University of Waterloo researchers found in May that data showed nearly a quarter of Canadians reported high levels of anxiety – numbers largely unchanged since 2020.

Their survey found that 23 per cent of Canadians are facing high anxiety, while 15 per cent are experiencing high depression, and that patients suffering from long COVID are at higher risk.