Moderate symptoms still cause long-term cognitive consequences, Oxford University researchers reveal
Scientists from Britain's Oxford University have revealed that people who have had mild Covid-19 and didn't suffer from other widespread 'long Covid' symptoms in daily life still show degraded attention and memory for six to nine months after infection.
Participants of the latest study had tested positive for Covid-19 previously, but didn't report any 'long Covid' symptoms often present after acute infection, nor other health concerns after recovery. They were not much different from an uninfected control group at the time of testing on factors such as fatigue, forgetfulness, sleep patterns or anxiety.
These people were asked to perform a series of exercises with a focus on activities essential for everyday life, such as sustaining attention, planning, memory and reasoning.
As a result, the scientists found that participants performed well in most tasks, but were significantly worse at recalling personal memories for up to six months after recovery. They also displayed a decline in ability to sustain attention over time for up to nine months.
"What is surprising is that although our Covid-19 survivors did not feel any more symptomatic at the time of testing, they showed degraded attention and memory," said Dr Sijia Zhao of the Department of Experimental Psychology, University of Oxford. "Our findings reveal that people can experience some chronic cognitive consequences for months."
Checking their colleagues' discovery, Stephen Burgess of the MRC Biostatistics Unit at the University of Cambridge pointed out the small group of people involved, adding that it was not randomized.
"However, despite this, differences between the Covid and non-Covid groups in terms of several specific measures of cognitive ability looked at in this study were striking, particularly in terms of delayed memory tasks and ability to perform tasks accurately when fatigued," he said.
Previously, studies have shown that after an acute Covid-19 infection some people continue to suffer from cognitive symptoms such as difficulties in concentrating, forgetfulness and fatigue, which are referred to as "long Covid" symptoms. However, little is known about whether a mild Covid-19 infection affects cognitive performance as well.