An analysis of brain scans from people once infected with COVID-19 suggested a consistent pattern in loss of grey matter over time, researchers say.
Researchers affiliated with the University of Oxford posted findings ahead of peer review this week to medRxiv, drawing on data from the U.K. Biobank. They compared brain scans taken pre-pandemic to scans taken about three years later among 394 coronavirus patients and 388 matched controls. A further analysis included 15 hospitalized patients compared with 379 people who hadn’t been hospitalized.
“Our findings thus consistently relate to loss of grey matter in limbic cortical areas directly linked to the primary olfactory and gustatory system,” or areas in the brain related to the perception of smell and taste, authors wrote.The initial set of scans taken before the pandemic strengthens the findings, study authors say, because they help differentiate the effects of COVID-19 disease from patients’ preexisting health conditions.
Researchers said the three areas revealing a “significant loss” in thickness and volume of grey matter among COVID-19 patients was the “parahippocampal gyrus, the lateral orbitofrontal cortex, and the superior insula,” later adding that the “strongest deleterious effects of COVID-19 could be seen predominantly in the left hemisphere.”
Results from the comparison of hospitalized patients “were not significant,” but authors noted “comparatively similar” findings to the larger group of coronavirus patients, “with, in addition, a greater loss of grey matter in the cingulate cortex, central nucleus of the amygdala and hippocampal cornu ammonis.”