This process, the sense of smell, provides a person with an invaluable perception of the environment around them. While my head trauma was rather significant, the loss of the olfactory is often experienced even after mild concussions. I've heard burnt milk, stale or hot bleach, diesel…. Serge Negus describes phantosmia, which he has experienced following brain damage incurred during a skate board accident. Kathleen Bainbridge: Well yes, actually, that's a nice way to put it. People who experience these unpleasant phantosmia often seek treatment, which can include saline sprays, antidepressants and antiseizure medicines. I've had days when I've been overawed by the most unnatural and unpleasant smells that are almost indescribable, smells that I can only imagine coming from another planet. But these treatments may not always work, and if the phantosmia is affecting the person's quality of life, there are even surgical options to remove parts of the olfactory system. We looked at a variety of health conditions and the two major factors that stood out were people who had a history of head trauma, people who had lost consciousness, and also people who reported symptoms of dry mouth, or persistent dry mouth symptoms. So it's an odour perception for which there is really no source, no identifiable source in the environment. Serge Negus, Writer: 1 to 38 the Jarryd Hayne Story. A skateboarding accident left Serge Negus with olfactory hallucinations. My co-author Dr Don Leopold, he has described people who have ripped up carpeting in order to try to find the source of the odour and there really is nothing to be found. And if you were wondering, yes, I still ride my skateboard, but nowhere near as fast. On a personal level, I can assure you it's a very odd experience to have this occurring every so often in your daily life. To find out how common it is and what factors might be linked to it, Kathy Bainbridge and her colleagues at the US National Institute on Deafness and Other Communications Disorders studied a large population in the United States. But phantosmia can have debilitating effects on people, especially when the smells that someone is experiencing are particularly unpleasant, most commonly described as burnt, spoiled or rotten in nature. This occurs when an area of hyper-functioning brain cells creates a perception of smell that is a total construction of the mind or, in other words, a genuine hallucination. James Bullen: How did you feel when you realised that was happening? Robyn Williams: Serge Negus, old friend, I'm relieved. They might try some medications such as antidepressants or anti-seizure medications I've heard are tried. The olfactory nerve is considered one of the most fragile nerves in the brain. Right now I can smell the classic mixed aroma of batter and grill, which is strange as I am nowhere near a fish and chip shop. The worst thing I've had, which I actually kind of liked, was the smell of fresh cow manure. Kathleen Bainbridge: You know, there is really no evidence-based treatments for phantom odours. Norman Swan: Okay, so having raised this on the Health Report, we are leaving people hanging a little bit in terms of what they can do about it, but at least they are recognised for the first time. Kathleen Bainbridge: It has never been studied in such a large population as the study that I participated in. People in those groups were also much more likely to report phantom odours. Norman Swan: Well, thanks for helping us out with it. James Bullen: And do you ever get the bad smells or has it pretty much been good for you? Robyn Williams: And so to two examples of broken brains, the first from Serge Negus. So what factors…because this was the other thing you looked at, is what predicted whether someone had a phantom odour, because it sounds from this that you've probably underestimated…if you haven't looked for the good odours, you've probably underestimated the phantom odour prevalence, but let's put that to one side. The second is a central theory, where a sense of smell is generated in the integrative or interpretive centres of the brain without the presence of any external stimulus. Serge Negus on phantosmia, spelled with a 'ph'. But no, I've never had any of the bad ones. This is called phantosmia, from the Greek words phantasm, meaning illusion, and osme meaning smell. Kathleen Bainbridge: In the United States there is an ongoing national health survey and it has been going on in its current form since 1999. But because, like I said, I've had this positive experience with phantom smells, I look forward to them when they do happen, and so I'd actually like them to happen more. For me, I don't think I'll ever need any of these. Serge Negus: You can get really bad smells with these phantom smells, things like burning flesh or these sorts of things or really unnatural smells. View Serge Negus’ profile on LinkedIn, the world's largest professional community. My straight answer is certainly not, but what I have gained through the loss of my smell and subsequent phantosmia is the realisation of what I consider to be the trickery of the brain, how in the absence of one of its primary sense receptors such as smell, the brain can overcompensate for its loss. There are a couple of theories out there, one is that the nerve cells that are in your nasal passages that pick up odours, odour sensing neurons, that maybe they are over-reactive, 'overachievers'. And beginning in 2011 we had the opportunity to add a battery of smell and also taste questions and a couple of different physical exams. Rather, the problem lies with the loss of the ability to smell. Norman Swan: Were you able to correlate this with taste, because taste goes along with smell and if you are smelling something odd you might be tasting something odd. Just as people experience phantom limb syndrome, I appear to be experiencing phantom nose syndrome. Sturge Weber syndrome (also known as Sturge Weber disease or encephalotrigeminal angiomatosis) is a Serge Negus: When an odour molecule floating through the air passes into your nasal passage and then bumps into the roof of your nose, it stimulates the olfactory nerve, and like a USB that you've just connected to a computer, the nerve starts to interface with the brain. When a skateboarding accident left Serge Negus with no sense of smell, he shrugged it off. If a stimulus was put under my nose, such as lavender oil, and I would inhale as much as possible, I would smell nothing. Phantom odour perception can be incredibly distressing. I didn't get that. Norman Swan: But some phantom odours are quite pleasant, aren't they? Norman Swan: It's under the radar really, this issue. Apparently some people have tried to have their olfactories removed completely to try and stop it but I don't know if it even works, the science around it is not that strong I believe. Norman Swan: Phantom odour perception is where you perceive an odour which when you search for it in your immediate environment you can't find where it's coming from and it in fact turns out not to be real. Kathleen Bainbridge: Women were much more likely to report phantom odours than men. But phantosmia can have debilitating effects on people, especially when the smells that someone is experiencing are particularly unpleasant: most commonly described as burnt, spoiled or rotten in nature. A saline wash can eliminate the phantom, at least for a while. Listen to this episode of The Science Show. One of the things that my mum did when she came in was put some lavender oil on my sheets at the hospital bed and then she presented the lavender oil to my nose and I literally couldn't smell it, and so that was when I discovered that I couldn't smell anymore.