Joy Milne’s husband was diagnosed with Parkinson’s when he was 45, but she felt something was off a few months earlier. She said his smell was different – a subtle difference, but a noticeable one.

“His smell changed and it seemed difficult to describe. It wasn’t all of a sudden. It was very subtle – a musky smell. I got an occasional smell.” [source]

Illustration of Parkinson’s disease by William Richard Gowers, which was first published in A Manual of Diseases of the Nervous System (1886)

Initially, she didn’t pay much attention to it, until she joined the charity Parkinson’s UK  and met people with the same distinctive odor – they all had Parkinson’s. She mentioned this to one of the scientists working with the charity and they decided to test her. The tests were conducted at Edinburgh University in Scotland, and she was surprisingly accurate.

Dr Tilo Kunath, a Parkinson’s UK fellow at the school of biological sciences at Edinburgh University describes how the test worked:

“The first time we tested Joy we recruited six people with Parkinson’s and six without. We had them wear a t-shirt for a day then retrieved the t-shirts, bagged them and coded them. Her job was to tell us who had Parkinson’s and who didn’t. Her accuracy was 11 out of 12. We were quite impressed.”

It gets better

But she insisted that she didn’t make a mistake; she continued to claim that the 12th subject also had the disease.

Dr Kunath adds:

“She got the six Parkinson’s but then she was adamant one of the ‘control’ subjects had Parkinson’s. But he was in our control group so he didn’t have Parkinson’s. According to him and according to us as well he didn’t have Parkinson’s.”

Unfortunately, he did have Parkinson’s; he just hadn’t been diagnosed.

“But eight months later he informed me that he had been diagnosed with Parkinson’s.  So Joy wasn’t correct for 11 out of 12, she was actually 12 out of 12 correct at that time. That really impressed us and we had to dig further into this phenomenon.”

That’s when they decided to analyze this phenomenon more. If odor testing could predict Parkinson’s even before conventional medical diagnosis, it could be a game changer. A simple, non invasive and cheap test to identify the disease accurately would be extremely useful, but that would just be the start.

If there’s something about Parkinson’s that does change a human’s smell, researchers can identify the molecule or molecules responsible for the change and see just what biological mechanism triggered it, better understanding the condition.

Katherine Crawford, of Parkinson’s UK says Parkinson’s is notoriously hard to diagnose in its early stages.

“We still effectively diagnose it today the way that Dr James Parkinson diagnosed it in 1817, which is by observing people and their symptoms. A diagnostic test like this could cut through so much of that, enable people to go in and see a consultant, have a simple swab test and come out with a clear diagnosis of Parkinson’s. It would be absolutely incredible and life-changing for them immediately.”

It may be an accidental discovery, but it’s an accidental discovery that can change the lives of many people – and even save them.