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October 26, 2020

Recovering smell lost through brain injury

How smell training can help recovery

Smell loss can be caused by many different things, with post-viral smell loss currently in the news due to COVID-19. But a lot of people lose their sense of smell following a head injury. We wanted to find out more about the causes of smell loss following a brain injury and what treatments might be available.

In our webinar on 13 October, we heard from Kim Price, a Patient Ambassador who lost her sense of smell following a head injury several years ago, and Dr Iordanis Konstantinidis, Associate Professor in Otorhinolaryngology, Aristotle University, Greece.

Head injuries, particularly traumatic brain injuries (TBIs), can be challenging in lots of ways, causing problems with many tasks and functions – and smell loss is often overlooked as a symptom while ‘bigger’ ones are focused on by both the person and their doctors. However, head injuries do not need to be severe to cause smell loss, and people and doctors should be on the lookout for it.

What might cause the loss of smell following a head injury?

There are different reasons that a head injury can cause smell loss, including damage to the nose itself that blocks the air flow, damage to the connections between the nose and the brain (the olfactory filaments), or damage to the part of the brain that processes smells (the olfactory bulb, as well as other parts of the brain).

If the damage is to the nose itself, treatment and surgery may fix this. Damage to the brain or olfactory filaments isn’t so easy to treat, but new MRI analysis techniques can help to better assess any damage and give a more accurate prognosis. Prognosis seems to be affected by the severity of an injury, how long smell loss has existed for, and age.

Smell training in people with TBI

Up to one-third of people may partially recover without any treatment, and a further 10-15% will recover completely. But what about treatments for the others?

One treatment that may help people who are experiencing smell loss as a result of head injuries is smell training. Although this won’t benefit everyone, research by Dr Konstantinidis has shown that it can help up to one-third of people.

Kim describes smell training as “a bit like physiotherapy for your nose.” It involves regularly smelling different scents to re-train your olfactory system and help it to heal.

You can read more about smell training, the evidence behind it, and how to create your own ‘smell kit’ in our smell training guide.