If you still don’t have your sense of smell back after suffering from long Covid, there are a few simple sniff tests you can do to rewire your brain.
Taking a sniff of things around the home that have a more pungent smell—such as lemon or orange rind, nutmeg, coffee or mint—twice a day can help the brain ‘remember’ smells, say scientists at University College London.
A loss of smell or taste, known as anosmia, was quite a common effect of catching the Covid-19 virus, and it’s proved to be a long-term problem for a minority of sufferers.
For those, the researchers have come up with a simple strategy to help them restore their sense of smell. They recommend smelling things that have a strong and distinctive smell several times a day twice a day for 10 seconds or so.
They had carried out MRI brain scans on people who had suffered nosmia after Covid infection and compared them to others whose sense of smell hadn’t been affected by the virus. They discovered that the SARS-CoV-2 virus had rewired the brain in those suffering a long-term loss of smell. Two parts of the brain—the orbitofrontal cortex and prefrontal cortex—had become ‘disconnected’ from each other and weren’t able to communicate smells.
Those who had lost their sense of smell had a heightened sensitivity to other senses, such as hearing, which suggests that parts of the brain were linking up to other senses. “This tells us that neurons that would normally process smell are still there, but they are just working in a different way,” said Jed Wingrove, one of the researchers.
Olfactory training—where the brain relearns the sense of smell through exposure to different stimuli—could help the brain recover lost pathways, the researchers say.