Monday, November 28, 2022 | Back issues
Courthouse News Service Courthouse News Service

New research links Covid-19 with long-term cognitive setbacks

Experts say a lack of oxygen and certain biological markers in the bloodstream are likely contributors to the cognitive dysfunction and Alzheimer’s symptoms found in recovering Covid-19 patients.

(CN) — Scientists revealed Thursday they have further explored the biological connection between contracting Covid-19 and potentially long-term struggles with cognitive impairment, lack of smell and even dementia-related symptoms.

While Covid-19 has been largely understood as a respiratory virus that targets an individual’s lungs and gastrointestinal systems, many who have contracted the virus since the dawn of the pandemic have reported a host of symptoms not typically found in infections similar to Covid-19. These have most notably included a loss of smell and taste, troubles with their attention span and a series of other cognitive issues often referred to as “brain fog.”

While these Covid-19 symptoms have been widely reported, scientists are still trying to unravel how exactly a respiratory illness can cause such a wide array of cognitive problems.

In an effort to help answer some of these questions, researchers and scientific leaders representing nearly 40 countries from across the world shared new information at this year’s Alzheimer's Association International Conference, held both virtually and in Denver, Colorado, that further cements the link between Covid-19 and long-term cognitive issues.

A big part of these new findings tie back to what happens with oxygen in the human body after it has caught Covid-19. Experts found that people who struggled with cognitive challenges after recovering from Covid-19 were far more likely to have low blood oxygen levels, especially after carrying out physically taxing tasks.

George Vavougios, postdoctoral researcher for the University of Thessaly in Greece, helped study 32 previously hospitalized Covid-19 patients in which over half of them struggled with cognitive decline at least two months after leaving the hospital and says the role of oxygen depravation in these trends needs to be fully explored.

"A brain deprived of oxygen is not healthy, and persistent deprivation may very well contribute to cognitive difficulties," Vavougios said. "These data suggest some common biological mechanisms between COVID-19's dyscognitive spectrum and post-COVID-19 fatigue that have been anecdotally reported over the last several months."

Experts also took a good look at biological blood markers — chemicals in the brain that tend to indicate some form of injury to the brain, like inflammation or Alzheimer’s disease — and their connection with Covid-19. To help study this, one team of researchers collected plasma samples from 310 patients who were admitted to New York University Langone Health with Covid-19. They found 158 of them struggled with neurological symptoms and that the most common symptom was confusion caused by toxic-metabolic encephalopathy.

Because they found that more patients who suffered from toxic-metabolic encephalopathy had higher levels of biological markers in their blood, experts believe those who contracted Covid-19 may experience an acceleration of symptoms typically associated with Alzheimer's.

A sudden loss of smell — another common symptom of Covid-19 that for many became one of their first noticeable indictors they had contracted the virus — also appears to plague patients looking to recover from Covid-19. A study of around 300 people in Argentina found that several months after catching the virus, more than half of them continued to grapple with forgetfulness and regular issues with their sense of smell, though many noted their olfactory impairments were not as bad as they were when they first got sick.  

While these results are largely centered around older adults, experts warn there may be much more to learn about Covid-19’s long-lasting side effects. Heather Snyder, Alzheimer's Association vice president of medical and scientific relations, says these troubling results highlight the need for even more research into the virus that has ravaged the lives of countless people across the entire world.

“These new data point to disturbing trends showing COVID-19 infections leading to lasting cognitive impairment and even Alzheimer's symptoms," Snyder said in a statement. "With more than 190 million cases and nearly 4 million deaths worldwide, COVID-19 has devastated the entire world. It is imperative that we continue to study what this virus is doing to our bodies and brains. The Alzheimer's Association and its partners are leading, but more research is needed."

Follow Carson McCullough on Twitter

Read the Top 8

Sign up for the Top 8, a roundup of the day's top stories delivered directly to your inbox Monday through Friday.