COVID-19 infection may result in objectively measurable cognitive deficits that can persist for a year or longer.
https://www.imperial.ac.uk/news/251734/covid-19-have-small-lasting-effects-cognition/
The NEJM study titled "Cognition and Memory after Covid-19 in a Large Community Sample" assessed over 112,000 participants using online cognitive tests between July 2021 and August 2022.
Researchers analyzed performance in memory, reasoning, and executive function across different groups: those who had COVID-19 with varying symptom durations and those who never had COVID-19.
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