In a startling new study, researchers and scientists at the University of Oxford’s Wellcome Centre for Integrative Neuroimaging have found changes in the brain structure of Covid patients, including those who experienced a mild infection. These changes are particularly noticeable in in areas of the brain involved in smell and memory processing.
According to the research report published in Nature, patients may suffer from cognitive deficit, experience brain tissue damage, and certain brain regions may experience losses resulting in the inability to smell following a Covid infection, even mild ones. Moreover, it has been found that the overall volume of the brain shrinks post-Covid in some people. These changes were observed several months after a Covid infection. However, the study doesn’t say if these changes are permanent or if they heal with time.
The study is based on the UK Biobank project, which has been monitoring the health of 5 lakh people for about 15 years. As a result, the project already had a comprehensive database of brain scans taken prior to the onset of the Covid pandemic, and researchers used participants from this study to examine the effect of Covid-19 on the human brain.
A total of 401 individuals from the biobank project aged between 51 and 81 were scanned, the majority of whom had suffered mild Covid infections. The scientists also examined 384 participants who hadn’t caught the virus.
The key findings from the study showed that the overall brain size of individuals with a mild Covid infection had shrunk between 0.2 and 2 percent. The research report observed that among those who had been infected with Covid, there was a greater reduction in grey matter thickness, greater tissue damage in regions of the brain connected with the olfactory or smell complex, and an overall shrinkage in size of the brain.
The authors of the study have stated that the findings could be the hallmarks of degenerative spread of Covid via olfactory pathways to the brain, either from loss of sensory input from anosmia (loss of smell) or by inflammation of the spinal cord and brain. They have, however, added that the implications of the visible brain changes are unclear, and the “highly plastic and flexible human brain” could still recover or even already be in the process of recovery for these patients.
In other words, the findings do not necessarily imply that Covid will affect memory or cognition in the long term, they said, and it is also unclear if the changes will affect a person’s quality of life in future. “Whether this deleterious impact can be partially reversed, or whether these effects will persist in the long term, remains to be investigated with additional follow up,” the authors wrote.