A recent study examining the lasting impacts of the coronavirus concluded that people living with long COVID who suffer from anosmia -- the loss of smell -- experienced a significant shift in brain activity.
Researchers from University College London found the link between smell loss and reduced brain activity after studying three groups of people: those with long COVID who lost their sense of smell, those whose smell returned after recovering from the virus, and those who never tested positive.
Loss of smell became one of the key symptoms of COVID in the early months of the pandemic, typically lasting one to two weeks. In some cases, though, symptoms have lasted much longer and any persisting longer than 12 weeks has become known as long COVID.
Using MRI scans, the neuroscientists determined the loss of smell is due to a change in the person's brain that stops it from correctly processing smells due to impaired communication between two parts of the brain. The UCL team studied the scans out of the United Kingdom during a six-month period during the second half of 2020.
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There is hope, they point out. A number of subjects participating in the study were able to reverse the alterations to the brain.
“Our findings highlight the impact Covid-19 is having on brain function. They raise the intriguing possibility that olfactory training – that is, retraining the brain to process different scents – could help the brain to recover lost pathways, and help people with long Covid recover their sense of smell," Professor Claudia Wheeler-Kingshott wrote. Wheeler-Kingshott was the senior author of the study.
Importantly, the group found people who regained their sense of smell did not suffer an "impaired connection between two parts of the brain with process important smell information."
Their study was published March in eClinicalMedicine.
"Our study gives reassurance that, for the majority of people whose sense of smell comes back, there are no permanent changes to brain activity," the study's lead author, Dr. Jed Wingrove, said.
The UCL findings also determined that long COVID patients dealing with anosmia might be compensating by increasing connection with different sensory regions of the brain.
