Researchers in the U.K. have been able to identify the specific compounds that make up an odour associated with people with Parkinson’s disease, thanks to the help of a grandmother who can smell the disease.

Joy Milne has been dubbed a “Super Smeller” by scientists who have marvelled at her ability to identify people who have the disease before they show any symptoms.

Parkinson’s disease is a neurodegenerative disorder that leads to progressive brain cell death and a loss of motor function. Symptoms can include tremors, shaking, and slowness of movement.

Milne first noticed the odour on her husband 30 years ago, according to Perdita Barran, a professor of mass spectrometry at the University of Manchester who worked on the study.

“She noticed his smell changed and she said to him he should wash more and he tried to, but there was no change,” Barran told CTVNews.ca during a telephone interview from Manchester on Tuesday.

In an interview with Agence France-Presse in 2015, Milne described the smell as a “heavy, slightly musky aroma.”

Nearly 10 years later, Barran said Milne’s husband was diagnosed with Parkinson’s disease at the age of 44.

The couple moved from the Manchester area back to their home in Perth, Scotland following the diagnosis. Milne’s husband started attending local support groups with other people who had the disease and it was there that she detected a familiar scent.

“She noticed at that point that the smell of other people in the room was the same as his,” Barran said.

Following her husband’s death at the age of 65 in 2015, Milne has worked with researchers to develop a diagnostic test for Parkinson’s disease before symptoms appear.

DETECTING SMELL

In the proof of concept study, published in the journal ACS Central Science, the researchers detailed how they were able to analyze the odours of 60 people, some who had the disease and some who didn’t, by using a technique called gas chromatography mass spectrometry.

During the study, researchers used gauze to swab the upper backs of the participants in order to collect samples of sebum, a waxy substance secreted all over the body that keeps skin supple and oily.

“We had thought that the smell would be in sweat, but it isn’t. It isn’t in sweat at all. It’s in sebum,” Barran explained. “It’s most prevalent in the T-area of your face, where you get spots when you’re a teenager, and the middle of your back.”

After collecting the sebum samples, Barran said they used a special instrument to detect and weigh particular molecules in the odours. She said the technique is commonly used in the perfume and food and drink industries.

Milne the “Super Smeller” was then given laboratory-prepared samples containing the same compounds identified in the technique. She confirmed the same musky scent she associated with Parkinson’s disease was present in the samples.

“Joy sat there [in a controlled olfactory environment] smelling with a little button and she would click when she smelled the smell,” Barran said.

The researchers said they were able to identify the presence of Parkinson’s disease in the subjects with 80 per cent certainty.

“We now have a library, a small library, of volatile biomarkers that we can use to diagnose Parkinson’s from people’s sebum,” Barran said.

Following the study, Barran said the researchers have collected sebum samples from more than 1,000 people from all over the U.K. She said they hope the findings will allow them to develop a simple, non-invasive test to detect Parkinson’s disease at an earlier stage.

“One in 15 people in the world will suffer from Parkinson’s. It’s a really prevalent disease. At the moment, while conditions can diagnose it, there’s no chemical signature, there’s no chemical test for it,” she said.

Barran said the smell seems to be apparent years before most people have symptoms and are diagnosed. She said using a smell test to detect the disease before symptoms occur may allow for earlier treatment and potentially preventive medicine.

“If we can do that with our test then we can start to work with drug discovery to see whether we can stop the symptoms at a much earlier stage,” Barran said.

For her part, Milne said she’s “absolutely amazed” by the work Barran and her team have completed for the study.

“It’s been superb. The support has been absolutely wonderful,” she told CTV’s Your Morning on Wednesday. “For people with Parkinson’s this is a game changer.”