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  • A new study published in JAMA Friday found that 24 percent of participants who recovered from COVID-19 had cognitive effects.
  • People who were hospitalized with COVID-19 were more likely to develop cognitive effects.
  • The researchers also noted that previous research found that older adults are more susceptible to cognitive impairment after being critically ill with COVID-19.

Many people who recover from COVID-19 go on to experience debilitating cognitive effects, including brain fog and problems with memory and attention.

A new study published in JAMA Network Open Friday found that 24 percent of participants who recovered from COVID-19 had difficulty with memory encoding, 23 percent had a hard time with memory recall, and 18 percent developed difficulties with processing information.

Patients who were hospitalized with COVID-19 or treated in an emergency room were more likely to develop cognitive effects compared to people diagnosed with COVID-19 who were treated in an outpatient setting.

Those who were hospitalized were 2.8 times more likely to experience difficulty paying attention compared to outpatients.

The researchers also noted that previous research found older adults are more susceptible to cognitive impairment after being critically ill with COVID-19.

According to Dr. F. Perry Wilson, a Yale Medicine physician and researcher at Yale School of Medicine, a lot of research has shown there’s a link between COVID-19 and long-term neurological deficits, but scientists are still learning about why this happens.

There are a few theories under investigation, said Wilson.

One is the widespread inflammation COVID-19 causes in the brain and body, another is the infection of brain endothelial cells, and the third is that COVID-19 causes tiny blood clots that can damage the small vessels of the brain.

“While the exact mechanisms have not been elucidated, it appears that COVID-19 exerts its effects through the SARS-CoV-2 virus itself as well as the inflammation the infection causes in the body,” Dr. Liron Sinvani, a hospitalist-geriatrician at the Feinstein Institutes for Medical Research in Manhasset, New York, said.

There is a well-established link between severe illness and cognitive impairment.

“If you look at studies of individuals who end up in the ICU, for any reason, about 66 percent or two-thirds will have some form of cognitive impairment assessed several months after that ICU stay,” said Wilson.

According to Wilson, critical illness, in and of itself, appears to cause cognitive effects due to inflammation, blood pressure shifts in critical illness that can injure the brain, and side effects from medications administered with ICU-level care.

Most of the research on cognitive effects with other viral infections has focused on patients who are severely ill.

Severe cases of flu can have devastating cognitive effects, but it’s less clear if milder cases cause cognitive impairment as well.

“It’s still an open question whether COVID-19 is unique in its patio-physiology or if it’s merely just a kind of severe illness” that has this cognitive effect, Wilson said.

Growing evidence suggests COVID-19 might be uniquely neurotoxic, and cause direct effects on the brain — but that’s not definitive yet.

“While other infections can lead to cognitive impairment or what can be referred to as ‘brain fog,’ it appears that COVID-19 is particularly impactful when it comes to cognitive impairment,” Sinvani said.

According to Sinvani, the vaccine is the most effective tool for preventing COVID-19 and therefore lowering the risk of cognitive impairment caused by COVID-19.

Most cases of post-viral cognitive impairment, such as brain fog, resolve naturally, but many patients who developed COVID-19 early on in the pandemic continue to experience effects.

“We know people have cognitive impairment over the course of months and then we have people who are now a year and a half out who still have deficits,” Wilson said.

It’s too soon to tell what the long-term cognitive effects will be in patients who survive COVID-19.

For people who are experiencing long-lasting concerns with cognition, it’s important to rehabilitate the brain — just as a person would rehabilitate other parts of their body, said Sinvani.

“If you suspect that your cognition has been affected following COVID-19, it is recommended that you contact your healthcare professionals for an official cognitive evaluation and to exclude any reversible causes, such as malnutrition,” Sinvani said.

A new study has found that many people who recover from COVID-19 develop cognitive effects related to attention and memory.

Though the link between COVID-19 and cognitive impairment is well-established, scientists are still learning about why long-lasting impairment occurs in some patients. Older patients and people who are hospitalized with the infection are more likely to experience post-viral cognitive effects compared to people with milder cases who are treated in an outpatient setting.