Acute COVID-19 infections can damage the brain, leading to complications like stroke and dementia-like symptoms, said a study published in Lancet last year. Neurologists from different parts of the world had earlier warned that COVID-19 does not only affect the lungs but also the brain in some cases.
Now a new UK study, that analyzed brain scans of before and after infection, has found that there is a substantial loss of grey matter in those who recovered from COVID-19. Experts believe that this loss of grey matter suggests brain damage.
Grey matter enables individuals to control movement, memory and emotions and loss of it may affect neurons functioning and communication.
What is the study?
The UK Biobank (UKB) is a data centre that collects and assesses genetic and health information. It has performed and collated brain scans of more than 40,000 participants before the start of the pandemic. Hundreds of these participants were invited for a second scan in 2021.
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Then a comparative study of these scans from 782 participants was performed to study the effects of novel coronavirus on the brain.
The UKB said that 404 of these participants were identified as those who had tested positive for COVID-19. Of these, 394 had scans that could be used for the study.
The researchers used structural and functional brain scans from before and after the Covid-19 infection, to compare changes in the brain between these 394 Covid patients and 388 controls (those who tested negative) who were matched for age, sex, ethnicity and interval between scans.
Majority of the examined covid patients showcased mild to moderate disease in the past. The study was uploaded to medRxiv on 15 June.
What are the findings of this study?
The findings of this UK study indicated that there was the loss of grey matter in areas of the brain linked to smell/taste, cognitive and memory functions.
“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),” the study found.
“The converging longitudinal analyses revealed a significant, deleterious impact of Covid-19 on the olfactory and gustatory cortical systems, with a more pronounced reduction of grey matter thickness and volume in the left parahippocampal gyrus, the left superior (dorsal) insula and the left lateral orbitofrontal cortex in the Covid patients,” the study, which claimed to be the first longitudinal imaging study in where Covid patients were initially scanned before they contracted the disease.
However, this study has not been peer-reviewed yet.
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Earlier a similar study by the Georgia State University had also found similar results where reduced grey matter volume was noticed in the frontal lobe of the brain of patients with severe COVID-19 who had a fever and required oxygen therapy. This study was published in the journal Neurobiology of Stress.