The study identified brain damage related to the coronavirus months after infection, “including in the region linked to smell, and shrinkage in size equivalent to as much as a decade of normal aging.” The changes were tied to cognitive decline in the study, which was published on March 7 in Nature, according to Bloomberg:
“It is a very novel study with conclusive data,” said Avindra Nath, clinical director of the U.S. National Institute of Neurological Disorders and Stroke, who was not involved in the research….The SARS-CoV-2 virus is widely considered a respiratory pathogen that attacks the lungs. Taking a narrow view of it, however, misses myriad neurologic complications — including confusion, stroke, and neuromuscular disorders — that manifest during the acute phase of the illness. Other effects like impaired concentration, headache, sensory disturbances, depression, and even psychosis may persist for months as part of a constellation of symptoms termed long Covid….the researchers found a greater reduction in grey matter thickness in the regions of the brain associated with smell, known as the orbitofrontal cortex and parahippocampal gyrus. The finding may help explain the impaired olfaction many Covid patients experience, as a result of either direct viral damage or inflammation spurred by the body’s immune response to the virus.
A loss of grey matter, which makes up the outer most layer of the brain, represents degeneration, said Leah Beauchamp, a neuropharmacologist at the Florey Institute of Neuroscience and Mental Health in Melbourne. “This is really concerning,” she said. The infected group also displayed a 0.2%-to-2% greater reduction in brain size compared with those who hadn’t been infected and showed greater cognitive decline based on their performance undertaking complex tasks. This was associated with atrophy, or shrinkage, in a specific part of the cerebellum — an area at the back and bottom of the brain — linked to cognition. Differences between infected and non-infected participants was more marked in older people.
Note, however, that much of this damage might be reversible. Bloomberg News quotes a neuroscientist saying, “The brain is ‘plastic’ and can heal itself.”