How can this woman 'sniff out' Parkinson's?
Retired Scottish nurse Joy Milne was asked to smell 12 shirts – half of which were from people with diagnosed Parkinson's. She stunned the scientists.
When UK-based chemist Perdita Barran first heard of a woman who could 'sniff out' Parkinson's, she had her doubts.
So along with her team of researchers, they put the person behind the claim, retired Scottish nurse Joy Milne, to the test. Milne was asked to smell 12 shirts – half of which were from people with diagnosed Parkinson's.
She stunned the scientists, not only correctly identifying the six that had Parkinson's but even pre-diagnosing another person who was diagnosed soon after.
Perdita Barran is the chairperson of mass spectrometry at Manchester University.
Manchester University / Drew Forsyth
Milne noticed she had this ability when she detected a change in her husband’s body odour six years before he was diagnosed with the disease. But it wasn't until she joined a meeting of people with Parkinson's that she made the link.
Her unique story made headlines around the world in 2015 and is helping researchers develop a swab test to detect the disease during its early stages.
The researchers found the smell was coming from sebum (a natural oily substance), specifically between the back shoulder blades.
Can we test for the smell?
Barran, the chairperson of mass spectrometry at Manchester University, says her field of study helps points to not only what the smells are but how much of the molecules are there that would point to Parkinson’s - and potentially other conditions. They are training AI to learn these consistent features too.
“We've certainly shown we can pick up other conditions with this method,” Barran told Sunday Morning.
“I think if we can prove that we can find other things, or even, for example, whether someone has Parkinson's and hypertension, Parkinson's and diabetes, which actually they're quite commonly correlated, then we start to be in a position where health authorities would be interested in this being a method that could be used routinely.”
Electronic devices could also be developed based on these biomarkers to indicate whether treatment has been effective or the condition is getting worse, she says.
“Particularly with people who've got genetic or familial risk of Parkinson's, we are working with trials that have been given to those people before they have motor symptoms to see whether we can determine the markers and how they change and whether they're suppressed and if the treatment's effective.”
Swabs could be banked over years – without the need for freezing – and used to develop a screening programme that can spot disorders in early life and in subsequent years, she says.
Do people want to know early?
About half of people with Parkinson's surveyed said they would have liked to have known earlier, but the other half said they would have preferred not to know until they could be treated, Barran says.
“But that changes when it's people who have a familial history, because I think they live more in awareness of it, of course, and somewhat in fear – so they want to know, yes or no.”
Do other diseases or illnesses smell?
Barran says paramedics are trained to be able to identify the smell of people with diabetes who may be having hypoglycemia – low blood sugar. It involves a build-up of fruity-smelling acidic chemicals called ketones in the bloodstream, which can lead to breath that smells “fruity or like rotten apples”.
Some bacteria are also known to smell quite different, she says. A 2023 study has looked at the diagnostic potential of breath analysis and noted how tuberculosis can smell like stale beer.
However, the researchers of that study said the success of diagnosing via breath smell is limited to laboratory settings. More clinical and large scale data was required to established how effective this method is.
People’s breath can smell like ammonia or urine when they experience kidney failure and those with liver disease may have a musty or rotten eggs breath. Although US medical research agency NIH noted in 2018 that such cases are rare.
Dogs have also been trained in studies around the world to sniff out some types of cancer, hypoglycaemia, malaria and Covid-19.
How does this happen?
Diseases alter the chemical composition of our body fluids, which in turn produces volatile organic compounds (VOCs) that can be released through our blood, saliva, urine and sweat.
Some of these VOCs release a specific odour fingerprint, which researchers hope can be used as biomarker or early indication of disease.
So can we train dogs and humans to sniff disease?
Humans aren't always great at being selective about smell, Barran says. (file image)
123RF
Not always, Barran says.
Each person has different capabilities. Milne’s case is quite special – she has hereditary hyperosmia. It’s a super-smelling condition that is said to be relatively rare.
Plus, Barran says humans are not always good at being “selective”.
“They won't be able to pull that out from all the other smells that are there with the person. So I think it would be difficult for anyone, and even people who are professional smellers, to really be trained in any large-scale way.”
There are also natural limitations. Milne, for example, can only do 10 samples a day before her ability to detect the disease doesn’t work anymore, Barran says.
That’s why machines are being trained, she says. Similarly, dogs are good at being selective and can work at a high rate, but the issue might be with training.
