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Photograph of a person completing his cognitive assessment and taking medications given by his caregiver as he recovers from COVID-19 months after infection.
The prevalence of psychological symptoms was investigated with detailed cognitive assessments of individuals who had been previously hospitalized for COVID-19.

Long-term Cognitive Impairment from Severe COVID-19

COVID-19-associated cognitive deficits similar to 20 years of aging

Photo portrait of Zahraa Chorghay
Zahraa Chorghay, PhD
Photo portrait of Zahraa Chorghay

Zahraa Chorghay, PhD, specialized in neuroscience during her undergraduate (University of Toronto) and doctoral studies (McGill University). She continues to explore her passion for neuroscience and for making science accessible and inclusive.

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Published:May 09, 2022
|1 min read
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Long-term effects of severe COVID-19 include persistent cognitive impairment. According to a study published in eClinicalMedicine, the magnitude of cognitive deficits experienced by individuals was correlated with the severity of acute illness recorded during their COVID-19-related hospitalization.

After SARS-CoV-2 infection, many people have reported psychological symptoms of fatigue, “brain fog,” and sleep disturbances. The prevalence of these symptoms is higher in severe cases, and is thought to be linked to a neuroinflammatory response persisting months post-infection. Instead of relying upon self-reporting, the recent study examines cognitive deficits following severe COVID-19 using a more objective, detailed, and computerized cognitive assessment.

Researchers performed cognitive assessments of 46 people who received critical care for COVID-19 at Addenbrooke’s Hospital, UK, between March 10 and July 31, 2020. Compared to 460 matched controls who did not have COVID-19, patients consistently showed reduced accuracy and slowed processing time across cognitive tasks. The cognitive underperformance was similar in magnitude to 20 years of cognitive aging, calculated as age-related decline in performance on cognitive tasks by people from the control dataset who were 70–79 years old minus those who were 50–59 years old. 

The observed cognitive deficits were uncorrelated to features such as mood, anxiety, fatigue, or post traumatic stress order (PTSD) at the time of cognitive assessment. However, the deficits were significantly correlated with the severity of acute illness recorded during their hospital stay. Individuals who had needed mechanical ventilation for COVID-19 significantly underperformed in the cognitive assessments. While some of these deficits may improve with time, this recovery is likely to be slow and dependent on complex factors requiring further research.