A woman who can “smell Parkinson’s” has helped scientists develop a test to detect the disease.
The test has been years in the making after academics realised Joy Milne, from Perth, Scotland, who has a heightened sense of smell, could detect the condition.
The 72-year-old noticed her late husband Les developed a different odour when he was 33 – some 12 years before he was diagnosed with the disease, which leads to parts of the brain become progressively damaged over many years.
Ms Milne described a “musky” aroma, different from his normal scent. Mr Milne died in 2015 aged 65.
Her observation piqued the interest of scientists who decided to research what she could smell and whether this could be harnessed to help identify people with the neurological condition.
Years later, academics at the University of Manchester have made a breakthrough by developing a test that can identify people with Parkinson’s disease using a simple cotton bud run along the back of the neck.
Researchers use the sample to identify molecules linked to Parkinson’s to help diagnose whether someone has the disease.
While still in the early phases of research, scientists are excited about the prospect of the NHS being able to deploy a simple test.
There is currently no definitive test for Parkinson’s disease, with diagnosis based on a patient’s symptoms and medical history.
If the new skin swab is successful outside laboratory conditions, it could be rolled out to achieve faster diagnosis.
Ms Milne said it was “not acceptable” that people with Parkinson’s had such high degrees of neurological damage by the time they get a diagnosis, adding: “I think it has to be detected far earlier – the same as cancer and diabetes, earlier diagnosis means far more efficient treatment and a better lifestyle for people.
“It has been found that exercise and change of diet can make a phenomenal difference.”
She said her husband, a former doctor, was “determined” to find the right researcher to examine the link between odour and Parkinson’s and they sought out Dr Tilo Kunath at the University of Edinburgh in 2012. Dr Kunath paired up with Professor Perdita Barran to examine Ms Milne’s sense of smell.
The scientists believed the scent may be caused by a chemical change in skin oil, known as sebum, that is triggered by the disease.
In their preliminary work, they asked Ms Milne to smell T-shirts worn by people who had Parkinson’s and those who did not.
Ms Milne correctly identified the t-shirts worn by Parkinson’s patients but she also said that one from the group of people without Parkinson’s smelled like the disease – eight months later that individual was diagnosed with Parkinson’s.
The tests have been successfully conducted in labs and now scientists are assessing whether they can be used in hospitals and eventually by GPs.
The findings, published in the Journal of the American Chemical Society, detail how sebum can be analysed with mass spectrometry – a method which weighs molecules – to identify disease.
Some molecules are present only in people who have Parkinson’s disease.
Researchers compared swabs from 79 people with Parkinson’s with a healthy control group of 71 people.
Ms Milne, who has a rare condition that gives her a heightened sense of smell, is now working with scientists around the world to see if she can smell other diseases such as cancer and tuberculosis (TB).
However, she described her sense of smell as a “curse and a benefit”.
“I have to go shopping very early or very late because of people’s perfumes, I can’t go into the chemical aisle in the supermarket,” she said.
“So yes, a curse sometimes but I have also been out to Tanzania and have done research on TB and research on cancer in the US – just preliminary work.
“So it is a curse and a benefit.”
Ms Milne said she can sometimes smell people who have Parkinson’s while in the supermarket or walking down the street but has been told by medical ethicists she cannot tell them.
“Which GP would accept a man or a woman walking in saying ‘the woman who smells Parkinson’s has told me I have it’? Maybe in the future but not now,” she said.
Prof Barran said: “At the moment, there are no cures for Parkinson’s, but a confirmatory diagnostic would allow them to get the right treatment and get the drugs that will help to alleviate their symptoms.
“There would also be non-pharmaceutical interventions, including movement and also nutritional classes, which can really help.
“And I think most critically, it will allow them to have a confirmed diagnosis to actually know what’s wrong with them.”
Additional reporting by Press Association