Is loss of taste and smell among COVID patients related to brain?
There has been extensive evidence of brain-related pathologies associated with COVID-19 disease throughout the pandemic, even asymptomatic cases widely reporting the loss of the senses of taste and smell which is brain-related.
By Newsmeter Network Published on 18 Jun 2021 1:23 PM IST
Hyderabad: There has been extensive evidence of brain-related pathologies associated with COVID-19 disease throughout the pandemic, even asymptomatic cases widely reporting the loss of the senses of taste and smell which is brain-related.
In a study `Brain imaging before and after COVID-19 in the UK Biobank' published in medRxiv, participants who took part in a brain study prior to the onset of the COVID-19 pandemic, were invited back for a series of follow-up tests, revealing significant losses of grey matter surrounding the olfactory(part of brain detecting odor) and gustatory(part of brain detecting taste) system in those that had been infected with severe acute respiratory syndrome Covid19.
Most of the Covid patients examined had had mild to moderate disease in the past. The Covid 19 infection leads to neurologic damage in some portion of people. The severity of neurologic effects is not related to the severity of the initial disease of these people.
Around 394 individuals participated in a prior study at the UK biobank and after that, they contracted COVID-19. Both resting and task functional MRI was performed to assess the functional connectivity between brain regions, and blood flow imaging was also employed. Imaging-derived phenotypes (IDP) were generated for the participants using these scans and compared with those collected before the pandemic.
Comparing the Covid-19 and non-Covid19 IDPs indicated a significant difference in the volume of the thalamus with those having virus exhibiting a reduction in grey matter. Thalamus functions are relaying of sensory signals, including motor signals to the cerebral cortex and the regulation of consciousness, sleep, and alertness.
The researchers said that the parahippocampal gyrus, lateral the orbitofrontal cortex and superior insula of the left hemisphere are the earliest cortical relays of the olfactory and gustatory system and were the most significantly influenced regions of the brain during Covid19 infection.
The olfactory bulb has been thought to be the entry point of Covid19 into the central nervous system, and the magnitude of effect at these locations.
Many of the results are strikingly similar to those associated with Alzheimer's disease or other forms of dementia. This has raised concerns that the long-term consequences of COVID-19 may include these disorders.
medRxiv published preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.
