The study on the potential impact of Covid on the brain was just published. The loss of gray matter, reduced brain size, and cognitive decline are concerning and need to be placed in context.
If you want to know if the Covid infections can damage the brain, you should have a brain Scan before and after the Covid infections, and a control group of people who also had two sets of brain images. In the United Kingdom, tens of thousands of people who had signed up for the UK Biobank underwent a brain Scan before the Pandemic and a subset of them were brought back at an average of three years later. Basic cognitive testing was done with their brain scans.
At the time of their baseline scans, there were about 400 participants in each group, aged between 47 and 80. 98% of both groups of white ethnicity were not diverse. The results of the analysis were unaffected by the deletion of the small number of people requiring hospitalization. Older white adults with mostly mild Covid are the focus of the study.
The control group saw a small loss of gray matter each year. The people with Covid in this study had more gray matter loss than the control group. The loss of gray matter and the damage to the brain were related to smell. There was a decline in the cognitive test among the group with the brain infections. There was no difference in memory testing results between the two groups.
What does this mean? It is a unique study design that is hard to duplicate. We don't have that yet, so we can't consider the findings conclusive. The lack of knowledge about symptoms in the Covid group, such as loss of smell, and reliance for classification on different Covid tests, some of which do not have high accuracy are some of the uncertainties. Was the two groups balanced? There was a subtle pattern of lower cognitive abilities in the participants who went on to be HIV positive. The results of serial testing and comparison with controls would not be affected by this. Even though it is the largest study of its kind, it doesn't preclude small differences between groups that may have influenced the findings.
The mechanism for the structural brain changes is not certain, but it is likely caused by inflammation from the nose. The path to brain damage is supported by most studies of Covid and the brain. The sense of smell and the limbic system are related to the brain regions most affected by the Covid group. The current study looked at whether the process is specific to this virus by comparing Covid brain images with a small number of people with either influenza or pneumonia, and not seeing a similarity in pattern.
This was not a study of long Covid. The symptom of brain fog that is commonly reported in people suffering from long Covid and has been likened to cancer therapy is not related to the current report. The memory of the Covid group was not impaired after four months, and there were no symptoms. The single assessment raises the question of whether the structural changes and cognitive decline may have reversibility. Brain cells do not have a high ability to regenerate, but they do have a high ability to form and reorganize synaptic connections. The flip side is1-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-65561-6556 One of the classic patterns of brain scans of Alzheimer's disease is limbic system atrophy, a modest degree of which was seen in the Covid group. Brain scans are essential for determining potential recovery or progression.
Is the findings applicable to younger adults and children? In the present study, the evidence of cognitive decline was mostly seen in people older than 70. Structural or functional brain changes in young people are yet to be established. Evidence of brain impact must be considered as an association since proof of Covid causality is not certain.
The Omicron strain is thought to have been transmitted to 40% or more of Americans and Europeans in recent months. It is important to note that the loss of smell was less with Omicron than with Delta and prior versions. The liability for brain effects of Covid would be less likely with Omicron. For reasons yet unexplained, Omicron has less tropism to the olfactory bulb, the neurons at the base of the brain specialized in smell.
We have come a long way from considering severe Covid pneumonia as the sole concern. It is vital that we keep a high regard for the potential liability and unpredictability of even mild infections, because the list of uncertainties about Covid's deleterious impact on the brain is long and uncertain.
All Rights Reserved © 2024
