Parkinson’s disease is a progressive neurodegenerative disorder marked by tremors and movement difficulties. It leads to progressive brain cell death and extensive loss of motor function. It is one of the most common age-related disorders affecting an estimated seven million to 10 million people worldwide.
Yet, as common as it is, and despite much research being conducted, there is still no definitive diagnostic test available for it. However, the nose for detail of a super-smeller from Perth, Scotland has uncovered an olfactory signature to Parkinson’s that researchers hope will lead the way to create a method for early detection of the disease.
The Super Smeller
A few years ago, a woman named Joy Milne detected a change in her husband’s scent several years prior to him being diagnosed with the disease. Upon his diagnosis, she joined the charity Parkinson’s UK and, lo and behold, met others with the same, distinct smell. That’s when she realized there was a connection between the subtle, musky odor and Parkinson’s.
“With my husband, I found when his symptoms worsened, the smell became stronger, and when he was balanced with his pills, the smell was less.” – Joy Milne
Smell Test
She shared this observation with some researchers. They tested her claim by having her sniff 12 T-shirts: six that belonged to people with Parkinson’s and six from healthy individuals. Milne correctly identified 11 out of 12. The 1 she had miscategorized was only incorrect at the moment. It turned out that she was not wrong at all because that person would be diagnosed with Parkinson’s less than a year later.
Source Of Smell
The location where the smell was coming from was the collar. This was a very important clue since sebaceous glands, which secrete an oily, waxy substance called sebum, are concentrated around your back and T-zone area—the forehead, nose, and chin. This pinpointed sebum as the source of the smell. As they started looking into this, they found that researchers had identified changes in sebum production on Parkinson’s patients’ skin as early as the 1920s.
Smell Test On A Molecular Level
Initial analysis was conducted with mass spectrometry – a technique used in chemistry to identify the amount and type of constituents in a sample – by researchers at the Manchester Institute of Biotechnology (MIB) to identify the molecular compounds that give the condition this unique odor.
The team analyzed the volatile components from the sebum found on people who have been diagnosed with Parkinson’s by collecting sebum samples using gauze to swab the upper backs of more than 60 subjects, both with and without Parkinson’s. After analyzing the sample data, they found the presence of hippuric acid, eicosane, and octadecanal.
These substances are the indicators to the altered levels of neurotransmitters found in Parkinson’s patients, along with several other biomarkers for the condition. The researchers then generated a model according to the levels of these molecules found in the test samples. With this model, they can now identify and diagnose Parkinson’s at all stages of the condition. The new research was published in the journal ACS Central Science.
Professor Perdita Barran, Professor of Mass Spectrometry in MIB, said:
“Now we have proved the molecular basis for the unique odour associated with Parkinson’s we want to develop this into a test. This could have a huge impact not only for earlier and conclusive diagnosis but also help patients monitor the effect of therapy. We hope to apply this to at risk patient groups to see if we can diagnose pre-motor symptoms, and assist with potential early treatment.”
“More research is needed to find out at what stage a skin test could detect Parkinson’s, or whether it is also occurs in other Parkinson’s related disorders, but the results so far hold real potential. Both to change the way we diagnose the condition and it may even help in the development of new and better treatments for the 145,00 people living with Parkinson’s in the UK.”
Dr Monty Silverdale, Consultant Neurologist and Honorary Senior Lecturer in Neuroscience at The University of Manchester added:
“We acknowledge this is a small study but it does open the door to the development of a non-invasive screening test for Parkinson’s, potentially leading to earlier detection for thousands of patients.”
What The Test Would Look Like
According to Barran, either a dipstick biosensor—which would work something like a pregnancy test, indicating whether specific biomarkers are present or absent—or a portable version of a mass spectrometer, which could not only identify what is there but how much. Another, potentially faster method for developing a diagnostic tool is training so-called detection dogs. Such animals are already in use to detect some types of cancer.
Tests using skin swabs, breath analysis, and detection dogs are attractive because they are noninvasive. Whatever the method may be, detecting the disease early can make a world of difference, especially with the emergence of new drugs that may be effective in slowing progression if administered during the beginning stages of the disease.
“This could have a huge impact not only for earlier and conclusive diagnosis but also help patients monitor the effect of therapy. We hope to apply this to at risk patient groups to see if we can diagnose pre-motor symptoms, and assist with potential early treatment.” – Professor Perdita Barran
Improving The Odds
Although Milne’s husband died from the disease in 2015, her remarkable discovery lives on. It could soon improve the lives of millions around the world. The ability to detect and track this disease through volatile skin biomarkers has the potential to revolutionize diagnosis and treatment.
