Perte de l’odorat et maladie de Parkinson
Some people living with Parkinson’s disease experience partial or complete loss of smell (hyposmia and anosmia, respectively). It becomes more difficult for them to detect, identify and differentiate between smells. Since smell and taste are closely intertwined, the latter can also be affected.
Hyposmia in the general population: 15%
Hyposmia in those with Parkinson’s: 70-90%
Anosmia in those with Parkinson’s: ⅓
Loss of smell can occur several years before the onset of the motor symptoms of Parkinson’s disease. Of course, not everyone who experiences loss of smell will develop Parkinson’s disease.
Loss of smell often goes unnoticed. When people do notice it, they tend not to realize that it can be associated with Parkinson’s disease. When the motor symptoms appear and they discuss the disease with their doctor, many patients remember having lost their sense of smell years earlier.
Here are a few of the ways in which hyposmia and anosmia can affect daily life:
- Difficulty choosing food
- Loss of interest in eating, followed by weight loss
- Difficulty identifying potential danger (fire, spoiled food, etc.)
- Sadness, depression
- Difficulty adhering to social standards of hygiene (difficulty detecting body odour)
Loss of smell is an important lead for researchers that could contribute to earlier Parkinson’s diagnoses.
Loss of smell in people with Parkinson’s disease can have several causes.
In the theory that Parkinson’s disease is linked to environmental factors, toxins are inhaled, destroying the region of the brain that processes odours. The degeneration then progresses to other parts of the brain, such as the one responsible for automatic movement.
However, there are many factors other than Parkinson’s disease that can affect sense of smell, including aging.
The following factors can lead to loss of smell:
- Sinus infections
- Damage to the olfactory nerves
- Poor oral hygiene
- Oral infections
- Old age
- Viral hepatitis
Loss of smell can be difficult to recognize because it occurs gradually.
People living with Parkinson’s disease often have difficulty recognizing the smell of bananas, licorice and dill pickles.
Other signs of hyposmia include:
- Difficulty distinguishing flavours or smells
- A perception of smells and tastes that differs from those around you
- The perception that food tastes bland
- Adding a significant quantity of salt or spices to food
If you have some of these symptoms, discuss them with your doctor. They will be able to administer olfactory tests or brain imaging to determine whether you are experiencing loss of smell.
7 out of 10 people don’t know that they have hyposmia until they are assessed.
Our sense of smell plays a vital role in alerting us to dangers in our environment (fire, spoiled food, etc.).
- Tell those close to you about your loss of smell. Don’t hesitate to ask them for help with activities that rely on smell, such as cooking or putting on scent.
- Make sure that the fire and/or smoke detectors in your house are working.
- Be vigilant when cooking, because some odours may be more difficult to detect (e.g. burning oil).
- Always check the expiration date on your food to make sure you don’t eat anything spoiled.
- Pay close attention to your hygiene. You may not be able to detect body odour, which could make others uncomfortable.
With loss of smell, food may seem bland. Consult a nutritionist for advice on how to regain the joy of eating.
You can also explore new spices and foods to broaden your range of odours and stimulate your appetite.
There is currently no medication that can help you regain your sense of smell. However, some patients who undergo deep brain stimulation surgery experience slight improvement.
You can help your loved one with activities that rely on smell. For example, they may need assistance with cooking or personal hygiene.
Loss of smell can affect sense of taste and appetite. It’s a good idea to take your loved one to see a nutritionist, who will be able to help them regain the joy of eating.
Explore new spices and foods with your loved one in order to broaden their range of odours and stimulate their appetite. You can discover new flavours together!
Finally, you can exercise their sense of smell by playing games that involve identifying spices blindfolded.
Loss of smell can occur up to 10 years before the onset of the motor symptoms of Parkinson’s disease. Its progression varies from person to person. For some, hyposmia will eventually lead to complete loss of smell. Others will remain able to smell some odours.
Loss of smell is currently being studied as a potential way to diagnose Parkinson’s disease earlier. Drugs could then be developed to halt the progression of the disease before the onset of motor symptoms.
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