BENGALURU: A unique study published in the journal Nature this week, said that Covid-19 causes some regions of the brain to shrink. This study has surprised many neurologists, who want to dig deeper into its findings. The study was done by researchers at Wellcome Centre for Integrative Neuroimaging at the University of Oxford. They studied magnetic resonance images taken before and during the pandemic, to compare morphological changes in brains of people who’d recovered from mostly mild cases of Covid, with those who hadn’t contracted it.
The study found Covid-associated brain damage in regions linked to smell, with a decrease equivalent to as much as a decade of normal aging. “The changes were also linked to cognitive decline,” the researchers stated in the study. Dr Sreekanta Swamy, Head of Neurology, Aster RV Hospital, told TNIE, “This is a very sophisticated study wherein MRI machines were all of the same type and same strength. According to this study, the brain shrinks by about less than 1 per cent, compared to before Covid infection, which is probably the reason why people develop fog, lack of concentration, lack of smell, etc.”
He explained that this study offers an explanation for patients developing ‘Long Covid’ symptoms. The frontal part of the brain controls memory and smell, so people have complaints of memory and concentration impairment, and smell defects. According to neurologists, the study is important as it could probably explain why and how there is damage which is localised to the radius concerned with the symptoms.
Dr NK Venkataramana, Founder Chairman & Director, Neurosciences, Brains Hospital, said post-Covid, a variety of neurological problems and symptoms have been observed, including headache, migraine, epilepsy, stroke, Bell’s palsy, brain fog and acute demyelinating syndrome of the spinal cord. “However, we do not have the experience of testing them for the presence of a virus. To the best of our knowledge, there is no such study in India. This study is interesting and could become a guideline for any study in future,” he added.
Sridharan Devarajan, Associate Professor at the Centre for Neuroscience, IISc, says the study was well powered and has reasonable samples. He said he would probably dig deeper into the study. “Covid-19 is a SARS-CoV-2 virus and is known to attack the upper and lower respiratory tracts, depending on the variant. One question I would like to probe is whether the researchers looked into the patients’ comorbidities, which are also said to be a reason for susceptibility to Covid infection,” he said.
He explained that it may be interesting to know how much of this has directly compromised brain function. If the virus has affected the lungs and respiratory tracts, there is also the possibility of it disrupting blood flow to the brain.
The researchers explain that the brain is “plastic”, meaning it’s able to reorganise itself by forming new neural connections to compensate for injury. There’s also emerging evidence that injured brain cells can undergo repair under the right conditions to help restore function. Researchers and neurologists in India claim that further research is needed to determine the impact of Covid-19 on the central nervous system and other organ systems in Long Covid patients.