Up to 70% of people with "long COVID" experience thinking and memory problems, according to a new study File Photo by Debbie Hill/UPI | License Photo
March 17 (UPI) -- About 70% of people who suffer long-haul COVID-19 experience concentration and memory problems several months after becoming infected, a study published Thursday by Frontiers in Aging Neuroscience found.
Many of them perform worse in tests intended to assess brain function than those who have not been infected with the virus or did not experience long-term symptoms, the researchers said.
In addition, roughly half of the "long COVID" patients in the study reported problems in convincing medical professionals to take their symptoms seriously, the data showed.
This may be due to brain-related symptoms not receiving the same attention as lung problems or fatigue, researchers said.
"People think that long COVID is 'just' fatigue or a cough, but cognitive issues are the second most common symptom, and our data suggest this is because there is a significant impact on the ability to remember," study co-author Lucy Cheke said in a press release.
"There is growing evidence that COVID-19 impacts the brain, and our findings reflect that," said Cheke, a researcher in psychology at University of Cambridge in England.
So-called "long COVID," or symptoms that persist for many months, may lead to long-term breathing and heart disorders, research suggests.
Long COVID has also been compared with chronic fatigue syndrome and linked with memory and mental health problems, as well as declines brain and kidney function.
As many as 75% of those infected with the virus experience symptoms for weeks, while others -- estimates vary -- still are sick for six to eight months after testing positive.
For this study, Cheke and her colleagues evaluated 181 long COVID-19 patients and monitored their symptoms over 18 months.
The majority of the participants had suffered COVID-19 at least six months before the study began, though very few had been ill enough to be hospitalized, the researchers said.
Of the study participants, 78% reported difficulty concentrating, 69% reported brain fog, 68% reported forgetfulness and 60% reported problems finding the right word in speech, the researchers said.
Participants were asked to carry out multiple tasks to assess their decision-making and memory, including remembering words in a list and remembering which two images appeared together, according to the researchers.
Their performance on these tests was compared to that of 185 people who have not had COVID-19, the researchers said.
The results revealed a consistent pattern of ongoing memory problems in those who had suffered COVID-19 infection, they said.
Thinking and memory problems were more pronounced in people whose overall ongoing symptoms were more severe, the data showed.
In addition, participants who experienced fatigue and neurological symptoms, such as dizziness and headache, during their initial illness were more likely to have cognitive symptoms later on, the researchers said.
Those who were still experiencing neurological symptoms, such as headaches and dizziness, were particularly impaired on cognitive tests, according to the researchers.
About 75% of study participants with severe ongoing symptoms of long COVID reported long periods of being unable to work, the data showed.
Study participants will continue to be monitored, using both symptom reports and objective cognitive tests, to see how long their symptoms persist, the researchers said.
"This is important evidence that when people say they're having cognitive difficulties post-COVID, these are not necessarily the result of anxiety or depression," study co-author Muzaffer Kaser said in a press release.
"Memory difficulties can significantly affect people's daily lives, including the ability to do their jobs properly," said Kaser, a researcher in psychiatry at the University of Cambridge.