New Study Links COVID-19 Infection to Subtle Cognitive Changes in Healthy Adults

A new study from Imperial College London’s COVID-19 human challenge trial has identified small but measurable changes in memory and cognitive performance among healthy participants infected with SARS-CoV-2. The findings, published in eClinical Medicine, show that these subtle changes persisted for up to a year, although all scores remained within the normal range, and no participants reported long-term cognitive symptoms like brain fog.

Subtle Cognitive Shifts in Controlled Conditions

The trial involved 36 young, healthy volunteers, 18 of whom became infected with the virus. Using the Cognitron platform to measure brain function in areas like memory, planning, attention, and problem-solving, participants were tested before infection, during quarantine, and over the following year.

The results revealed small declines in cognitive performance, particularly in memory and executive function tasks, among infected participants. These differences were not reported by the participants themselves, indicating that the changes were detectable only through sensitive testing.

“Our work highlights how respiratory infections can affect specific aspects of brain function,” said Professor Adam Hampshire from Imperial’s Department of Brain Sciences, now at King’s College London. “These effects are evident even under controlled conditions, suggesting infections like COVID-19 can subtly alter cognition.”

Limitations and Research Potential

While the observed changes were statistically significant, the differences were small, and none of the infected volunteers reported lingering cognitive symptoms. The study cautions that its small sample size, primarily consisting of white males, limits the generalizability of the findings.

The researchers emphasize that future studies could explore how respiratory infections, including RSV and influenza, compare to COVID-19 in affecting brain function. “Understanding these biological disruptions at a finer level may help us develop treatments to reduce these effects before they impact people’s lives,” explained Professor Christopher Chiu, co-author and lead of the COVID-19 human challenge study.

Lasting Cognitive Impacts of COVID-19

The study adds to a growing body of evidence that COVID-19 can have lasting effects on brain function, even in mild cases. Earlier research from Imperial College involving over 140,000 participants found similar cognitive impairments up to a year after infection.

“By using pre-infection baselines and monitoring participants closely, we detected subtle shifts that traditional studies may miss,” said Hampshire. “This detailed approach offers a new way to understand how infections alter cognitive pathways.”

The study was funded by the UK Vaccine Taskforce and supported by the NIHR Imperial Biomedical Research Centre.

Reference:
Trender, W., Hellyer, P. J., Killingley, B., et al. (2024). Changes in memory and cognition during the SARS-CoV-2 human challenge study. eClinicalMedicine. DOI: 10.1016/j.eclinm.2024.102842