The study authors noted that the imaging differences between the two groups were modest, at about 2% of average baseline values. The typical annual loss of gray matter each year due to aging, the researchers said, is 0.2% to 0.3%.
Cognitive tests identified differences between COVID-19 survivors and controls, including a significant increase in the time taken to complete Trails A (numeric; 7.8%) and B (alphanumeric; 12.2%) of the Trail Making Test in COVID-19 participants. These results held true when excluding the 15 hospitalized patients (Trail A, 6.5%; Trail B, 12.5%).
"The infected participants also showed on average larger cognitive decline between the two timepoints," the study authors wrote. "Importantly, these imaging and cognitive longitudinal effects were still seen after excluding the 15 cases who had been hospitalised."
Not all COVID survivors have brain changes
In addition to the modest COVID-19 effect, the study authors noted that the statistics represent an average effect, meaning that not every COVID-19 survivor will experience brain changes.
