Cognition and memory after Covid-19 in a large community sample (29 February 2024)

Summary

Poor memory and difficulty thinking or concentrating (commonly referred to as “brain fog”) have been implicated in syndromes occurring after Covid-19 — a situation that has led to suggestions that Covid-19 may have lasting cognitive consequences. However, objective data on cognitive performance are largely lacking, and how long such deficits may persist and which cognitive functions are most vulnerable are unclear.

In this observational study, Hampshire et al. invited 800,000 adults in a study in England to complete an online assessment of cognitive function. The authors estimated a global cognitive score across eight tasks. They hypothesised that participants with persistent symptoms (lasting ≥12 weeks) after infection onset would have objectively measurable global cognitive deficits and that impairments in executive functioning and memory would be observed in such participants, especially in those who reported recent poor memory or difficulty thinking or concentrating (“brain fog”).

They found that participants with resolved persistent symptoms after Covid-19 had objectively measured cognitive function similar to that in participants with shorter-duration symptoms, although short-duration Covid-19 was still associated with small cognitive deficits after recovery. Longer-term persistence of cognitive deficits and any clinical implications remain uncertain.