How Scent Loss But Recognizing Chili Pepper’s Spice Could Be a Predictor of Parkinson’s

In a press release by Parkinson’s Canada; researchers in Canada wanted to unpack why some people first lose their sense of smell before developing Parkinson’s disease with age. While losing one’s sense of smell doesn’t guarantee a life with the progressive illness, it can be an early warning sign, with a reported 95% of Parkinson’s patients losing their smell a decade prior or earlier.
Parkinson’s Canada awarded a $45,000 grant to Joannes Frasnelili, PhD, to find out more about how smell is sensed in the brain, and what it links to, in order to see if the mechanisms damaging Parkinson’s patients smell is unique from common causes. If so, they could  create a diagnostic tool to identify and begin treating these likely Parkinson’s newcomers before the disease progresses.

Parkinson’s Disease

Parkinson’s disease is a progressive disease of the central nervous system, which over time erodes a person’s control of their movement. Symptoms begin with stiffness and slight tremors in one hand, and progresses into slowed movement, slurred speech, rigid muscles, poor posture and balance, loss of muscle movement, and in some cases, hallucinations and dementia. The disease tends to only begin later in life, with most patients developing symptoms after age 50. While there are medications for symptoms as well as surgical options, there is no specific pharmaceutical or cure.

Their Unique Loss of Scent

While 20% of the population lose their smell as they age for a range of unrelated symptoms, those who lose it due to Parkinson’s uniquely maintain the ability to pick up on other characteristics. Frasnelli explains that Parkinson’s patients can still pick up on things like  “the freshness of plants like eucalyptus, or the spiciness of chili peppers.”
This is because those with Parkinson’s maintain aspects of smell carried out by the trigeminal system, a related sensory system that picks up on different characteristics through issue around the mouth, nostrils, tongue, teeth, and gums. It picks up on distinct quality such as spiciness or umami, functions which would typically also be lost in other patients who lost their olfactory functioning.

Frasnelli Studies Brain Activity

Frasnelli wanted to compare the brain functioning compared between these patients, those with a more typical cause of the loss of smell, and healthy people. He uses magnetic resonance imaging (MRI) to get a look at their brains, searching for unique patterns of brain activity in the patients with Parkinson’s. He predicted that the three groups would have unique brain activity. He’s building on prior research that looked into the electrical patterns in the tissues resulting from brain and smell impairments.
“I want to know to what extent looking at the sense of smell helps us to understand how the brain works, and how different parts of the brain work.”

A Diagnostic Predictor 

He believes this could be used as a diagnostic tool, and he hopes to create a more accessible preliminary version of this test. It could be used by physicians who could refer patients for more comprehensive testing for Parkinson’s. This would allow them to promptly begin treatment before the disease erodes the cells responsible for movement.
While this is only a pilot project now, it could be the building block for a more comprehensive study that could identify unique patterns in the brain that would act as predictors of Parkinson’s in some patients with smell loss. This can help them treat the condition before it progresses.
“I know a lot of people with the disease, and relatives of those people, and I see how difficult Parkinson’s disease is,” said Frasnelli. He witnessed the havoc of the disorder firsthand working with patients in a retirement home in Switzerland.
He believes the findings of this pilot project can lead to a follow-up study on how the coronavirus has left many patients without their sense of smell. Frasnelli speculates that this will have consequences— possibly likening their chance at developing Parkinson’s in the coming years.

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