Smell training has been demonstrated to improve patient outcomes where smell loss arises from upper respiratory illness and in some cases of brain injury. The deciding factor for TBI patients is how severe the injury to the olfactory nerve is--whether the nerve has been severed or just bruised.
I am aware that many patients are afraid to begin smell training for fear of being disappointed. "I'm not ready to start yet" is one comment I heard recently. Others dismiss the therapy, on the basis that it can't be for them. "I tried that once. It didn't work for me". They think it sounds implausible and are dismissive, which is a shame in cases where smell training may well be of benefit.
So often people in the Facebook groups say that they can "smell nothing" and yet go on to describe how they perceive unpleasant smells that can hamper their day to day experience. These messages are confusing. I can't smell, and yet I can smell all this terrible stuff. What's going on? And inevitably: is there any point in trying smell training?
I have a simple test. Find two foods. I have shown grapefruit and rosemary from my garden, but you may choose whatever you like, as long as they are foods with some smell. You will need to enlist a friend or a family member to help and you will need a blindfold. Line up your food and then smell the three items. Can you tell which one is the odd one out? If possible, swap the three items around, smelling them a couple of times each.
What does this exercise demonstrate? If you can choose the odd one out, then you have some, however minimal, sense of smell. The grapefruit and the rosemary may smell like nothing you can describe, and the smells might be disagreeable or just faint. But if you do, then there is some life left in your olfactory nerve. And if that is the case, then smell training, which is no more than mindfully stimulating your sense of smell repeatedly, will help regenerate your olfactory nerve. The mindfulness is key. We know from scientific studies that mindfulness training alters the structure of the brain. And this principle also holds for smell training. Read more here.
It has been five years since my smell loss from a virus and I consider myself healed and satisfied with my recovered sense of smell. I still have distortions, but things continue to improve. Will I ever experience the world of smell as I used to? Probably not. But am I still discovering new smells? Yes. And how can I be so sure that smell training helped me, rather than just random recovery? On my last Sniffin' Sticks test at the University of Dresden, I scored 46 out of a possible 48--right up there with a perfumer's "nose".