The mental fog and memory and concentration disturbances that persist for months after infection with Covid-19 could be related in some cases to changes in brain metabolism and the accumulation of molecules toxic to neurons.
Post Covid, mental fog and memory lapses
It is indicated by a research on seven patients coordinated by the University of Milan and conducted in collaboration with the Aldo Ravelli Center of the State University, the Asst Santi Paolo e Carlo and the Irccs Auxologico.
The results, which open up new questions about post-Covid damage, are published in the Journal of Neurology. The researchers, led by neurologist Alberto Priori, selected seven patients hospitalized for Covid who still had cognitive disorders detected by specific neuropsychological tests.
Changes in brain metabolism
These volunteers were examined with the method of positron emission tomography (Pet) to evaluate the metabolic activity of specific areas of the brain.
The reports revealed that three patients had impaired functioning of the temporal areas (site of memory function), of the brainstem (site of some circuits that regulate attention and balance) and of the prefrontal areas (which regulate energy mentality, motivation and, in part, behaviour).
Suspicious accumulation of amyloid in the brain
In one of these patients who had a more serious cognitive disorder, a special Pet was also performed that allows the deposition of amyloid in the brain to be visualized.
“Amyloid is a protein which, when it accumulates in neurons, determines their premature aging and degeneration and which is implicated in Alzheimer’s disease”, explains Luca Tagliabue, director of the division of Nuclear Medicine and Radiodiagnostics of Asst Santi Paolo and Carlo.
“Well, in the patient examined, Pet revealed an abnormal accumulation of amyloid in the brain and particularly in the frontal lobes and in the cingulate cortex, linked to complex cognitive functions and emotions”.
The researchers thus came to the conclusion that in just under half of the patients with memory and concentration disorders one year after Covid there may be functional alterations of the temporal, frontal and brain stem areas.
While in other cases cognitive disorders “do not have a functional response to the brain, but can derive from exclusively psychological changes similar to post-traumatic stress disorder”, explains Roberta Ferrucci, professor of psychobiology at the University of Milan.
The observation of increased amyloid in one patient, reported for the first time in this study, may be related to infection. Or the triggering of the neurodegenerative cascade by the infection. This data will have to be evaluated by future studies, to understand whether SarsCoV-2 infection could determine an increased risk of neurodegenerative diseases in the future.