Overview of Olfactory Training
About one in five people have issues with their sense of smell. Not being able to smell properly can make life less enjoyable, and it can also be dangerous. For example, you might not be able to smell gas leaks or smoke. Your sense of taste is also connected to your sense of smell, so if one is affected, the other might be too. This can lead to eating spoiled or contaminated food because you can’t taste that it’s gone bad. An impaired sense of smell can also be a warning sign of diseases like Alzheimer’s and Parkinson’s.
The most common reasons people lose their sense of smell are due to a disease in the nose, a viral infection, or a trauma to the face. If the problem is caused by a physical issue in the nose or brain, such as a tumor, treatment will focus on fixing that. This might involve surgery on the nose or brain.
For people whose sense of smell is damaged due to inflammation, toxins, trauma, viral infection, or unknown causes, olfactory therapy might be appropriate. Olfactory therapy is when you expose yourself to different smells twice a day over several months to retrain your smelling abilities.
Doctors might also prescribe medications like corticosteroids for inflammation in the nose. Other treatments like sodium citrate, zinc, and vitamins have been tried, but we don’t have solid proof yet that they work. It’s important to note that some studies on treating loss of smell have not been as rigorous as they should be. This means we need more research in this area.
On a positive note, some people’s sense of smell improves on its own. Up to one in five people with smell issues due to trauma and three in five people with issues due to a past infection get better without any treatment. Younger people, women, non-smokers, and people who still have some preservation of their sense of smell are more likely to see their sense of smell improve on its own. If you’re a smoker and you’re having issues with your smell, you should consider quitting. Smoking can make smell problems worse and may even interfere with attempts to improve your sense of smell.
Olfactory training is a simple treatment and hasn’t been linked to serious side effects so far. Although we don’t understand exactly how it works or how effective it is, olfactory therapy is increasingly being used to treat patients with a variety of smell issues.
Anatomy and Physiology of Olfactory Training
The olfactory system relates to our sense of smell and is highly interconnected with the part of our brain that controls emotions. When we inhale, tiny particles go into our nose where they dissolve in the mucus that lines the inside of our nasal cavity. These particles then interact with special smell sensors, which send smell signals to our brains. This all happens through a complicated pathway that starts at the smell sensors in our nose, goes through a part of the skull bone (called the ‘cribriform plate of the ethmoid bone’), enters the ‘olfactory bulbs’ (a part of the brain), and finally reaches the ‘olfactory cortex’ (the part of our brain that processes smells).
The smell sensors are located in the upper part of the inside of your nose. Sense of smell has many important functions including helping us to detect danger and identify food. Interestingly, our taste buds can only pick up five different types of flavours (sweet, sour, salty, bitter, and umami (a savoury taste)), while our sense of smell can identify a trillion different smells. This shows that our smell largely contributes to our sense of taste. Thus, if our sense of smell gets impaired, it affects our sense of taste as well. It’s worth mentioning that the way our smell signals reach our brain through small openings in the skull bone might be a possible way for infectious pathogens, like the new coronavirus, to enter the brain. Smell signals may be easily disrupted if there’s an injury to the face because the path they travel through is so delicate.
Unlike our other senses, our olfactory system (that includes the smell sensors in the nose and parts of the brain) has the unique ability to adapt and regenerate. Repeated exposure to different smells can enhance this process and improve how our sense of smell functions. This regenerative power of the olfactory system was first discovered in healthy individuals in the mid-1990s. Years later, it was found that repeated exposure to different smells can also improve the functioning of the olfactory system in individuals who had impaired smelling abilities due to various reasons. This has been confirmed through multiple studies over the past decade. Several studies on animals and brain imaging studies on humans further confirm that our olfactory training is effective.
Why do People Need Olfactory Training
Olfactory training, which is a process to improve your sense of smell, is generally more effective in younger people and in individuals who have severe problems with their sense of smell. However, this method can be used to help anyone, regardless of their age or how well they can smell. It can be particularly useful for several groups of people including:
Those who have trouble with their sense of smell after an infection: This problem often arises after a minor or serious upper respiratory infection, especially if it’s caused by a virus. It’s quite common for people with COVID-19 to experience this. If you’re tested, you’ll likely notice that your ability to smell and tell the difference between different smells has lessened, while your ability to identify specific smells is unaffected. A study showed that over one year, 71% of patients with this problem improved with smell training, compared to 37% who recovered without it. It doesn’t seem to matter if you’re a man or woman, or whether you drink alcohol, the training can help. In some cases, it might be combined with steroid treatment.
People who’ve had a brain or nasal injury: After an injury like this, you may suddenly or gradually find you have trouble with your sense of smell. Here again, smell training can help, but it may not be quite as effective as in those with smell problems after an infection. One study found that 23% of people improved with the training.
Individuals with Parkinson’s disease: If you have this condition, you’re likely to have a severe problem with your ability to smell. The issue can arise years before problems with movement like tremors begin. Unfortunately, medications for Parkinson’s don’t seem to help with this, so smell training could be a good option. However, its success rate is lower in people with Parkinson’s than after an infection—from about 20% to 10%.
If you’re diagnosed with idiopathic olfactory dysfunction, which means that no one knows why you’re having trouble smelling, you may be less likely to benefit from smell training. But it could still offer some improvement, and be worth trying.
When a Person Should Avoid Olfactory Training
There aren’t any known reasons, based on a person’s previous health history or medication use, why they shouldn’t undergo olfactory training. Olfactory training is a type of therapy designed to help people improve their sense of smell. However, it’s still not clear how effective this training is for people whose sense of smell has been impaired due to diseases affecting the nose and sinuses.
Many people who have a reduced sense of smell caused by sinus disease, particularly those with long-term sinus inflammation (with or without growths in the nose called polyps), may improve after a type of minimally invasive surgery known as functional endoscopic surgery. This is often combined with a period of treatment using nasal steroid sprays before surgery.
So, it’s generally suggested that these medical and surgical treatments are considered as the first step in managing patients with long-term sinusitis. Olfactory training might be considered when surgical treatments have been tried and didn’t work, cannot be performed, or have been completed.
Equipment used for Olfactory Training
When training your sense of smell, you would usually use four containers that you can sniff from, each holding around 50 mL. Each container has a cotton pad soaked in 1 mL of a different aroma. These scents are usually rose, eucalyptus, lemon, and clove.
Training your sense of smell like this is a straightforward way to get better if you’re having trouble with your smelling abilities. This type of treatment may be used in specialist clinics that deal with problems related to the senses of smell and taste, as well as more general practices that deal with issues related to the ears, nose, and throat.
Who is needed to perform Olfactory Training?
If you’re having trouble with your sense of smell (a condition called olfactory dysfunction), you might need to learn some exercises to help get it back. A doctor, nurse, nurse practitioner, or another medical person who knows a lot about smell problems can teach you these exercises. This process is often referred to as “olfactory training”, and it’s a way to help improve your sense of smell over time.
Preparing for Olfactory Training
To find out why someone’s sense of smell is not working properly, a thorough check-up needs to be done, following established rules agreed upon by experts. Also, patients should be clearly informed about the steps and techniques to be used in their smell training program.
How is Olfactory Training performed
Olfactory training is a treatment method used to improve the sense of smell. In a standard training session, patients are given four different scents to sniff individually for about 20 to 30 seconds without a break. They do this twice daily – ideally, once in the morning before breakfast and once in the evening before bedtime. The scents are provided in sniffing bottles or jars. This training process typically lasts for about 24 weeks.
Studies have shown that for patients who lost their sense of smell due to infections, training for a year or using twelve different scents can lead to better improvements. Furthermore, stronger scents may be more effective for these kinds of patients. However, these approaches haven’t been confirmed for patients who lost their sense of smell due to other reasons. For those patients, following the standard training protocol (four different scents, twice daily, for 24 weeks) might be the best way to start.
This process of olfactory training requires a lot of patience and discipline from both the patient and the healthcare provider. The improvements might be subtle and slow to be successful. To help patients stay consistent with the training, an olfactory training ball can be used. This ball is roughly the size of a baseball, is easy to hold, and has four tubes that contain different scents. Regular check-in appointments, say every six weeks, can also encourage patients to stick with the training and track their progress.
Possible Complications of Olfactory Training
Research on training people’s sense of smell has been done in over 40 clinical studies and reviewed in many independent studies. No complications were reported from training the sense of smell. However, some people may find it tiring to do these smell tests every day over the course of several months.
What Else Should I Know About Olfactory Training?
When it comes to problems with your sense of smell, called olfactory dysfunction, there aren’t many treatment options available. This is especially the case when the problem isn’t because of a viral infection or a long-term sinus condition, known as chronic rhinosinusitis. The main treatment available is olfactory training, which seeks to improve your sense of smell through exercises. This approach is particularly important when the cause of your smell issues doesn’t fall into the previously mentioned categories.