A new, preprint study published June 15, 2021, shows a startling new finding that better explains some of the long-term neurological effects of COVID-19, including the hallmark loss of the sense of smell that it causes.
United Kingdom researchers used a large database of brain images that were taken prior to the COVID-19 pandemic, then performed repeat testing on a segment of patients who developed a COVID-19 infection at some point during the pandemic. Researchers found changes in brain density and a loss of grey matter volume that had occurred in those who had been infected with COVID-19.
Researchers Say Parts of the Brain Altered by COVID-19
“All significant results were found in the primary or secondary cortical gustatory and olfactory areas, in the left hemisphere, using grey matter information (volume, thickness),” researchers wrote. These areas of the brain control the sense of smell and taste, offering a compelling explanation of why these senses are commonly affected by COVID-19 and why these symptoms persist indefinitely in some patients.
Because there may be some degree of neurological compensation, the sense of taste and smell may be somewhat restored, but this research would seem to indicate that lasting effects could be permanent.
“In short, the study suggests that there could be some long-term loss of brain tissue from COVID, and that would have some long-term consequences,” former FDA Commissioner Scott Gottlieb, MD, said in a recent interview. “You could compensate for that over time, so the symptoms of that may go away, but you’re never going to regain the tissue if, in fact, it’s being destroyed as a result of the virus.”
New Avenues of COVID-19 Research
“The diminishment in the amount of cortical tissue happened to be in regions of the brain that are close to the places that are responsible for smell,” Gottlieb continued. “What it suggests is that the smell, the loss of smell, is just an effect of a more primary process that’s underway, and that process is actually shrinking of cortical tissue.”
These new findings open a potential new avenue of research that is only beginning to be explored. The finding that at least some of the long-term symptoms of COVID-19 are explained by permanent loss of brain tissue may spur further research into where and how brain function could be affected by a history of COVID-19 infection.
As the interest in long-term COVID-19 symptoms and their causes continues to grow, emerging research, such as this from the UK, will enhance clinicians’ knowledge on the topic. The work may lead to new treatment options and new clinical tests.
Clinical laboratories that keep up to date on emerging long-haul COVID-19 symptoms will be positioned to quickly offer tests that are found to be connected with diagnosing long haul COVID-19.
—By Caleb Williams, Editor, STAT Intelligence Briefings
MedRxiv: Brain imaging before and after COVID-19 in UK Biobank
CBS, Transcript: Scott Gottlieb on “Face the Nation,” June 20, 2021
News Medical Life Sciences: Alarming COVID study indicates long-term loss of gray matter and other brain tissue