Joy Milne has always had a good nose. She is accustomed to being able to smell things that others can't. So when her husband's scent started to change, she attributed it to the long hours Les was putting in at his job as an anesthesiologist. Six years later, Les was diagnosed with Parkinson's disease at the age of 45. Milne didn't realize there was any connection between Les' musky odor and his diagnosis until she attended a charity Parkinson's event and noticed other people with the condition seemed to have that same distinct scent.

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Milne's discovery might just change the way Parkinson's is diagnosed and even treated.

It all started when Milne made an offhanded comment to some Parkinson's researchers about her olfactory observation. They were intrigued and decided to give her a test. They asked six patients with Parkinson's and six without to wear a T-shirt for a a day. Then they gave the shirts to Milne and asked her to tell them which were worn by the participants with Parkinson's and which were from the control group.

Milne was correct in 11 out of 12 of the cases. She was only off in one instance in which she insisted the participant had Parkinson's but he did not.

Parkinson's diseaseParkinson's disease affects more than 200,000 people in the U.S. each year. (Photo: Tashatuvango/Shutterstock)

The researchers were impressed with her accuracy. But things kicked up a notch when that one participant whose diagnosis Milne got wrong called eight months later to say that he had just been diagnosed with the disease. That meant Milne could smell Parkinson's even before symptoms were distinct enough to warrant a diagnosis.

“That really impressed us,” Edinburgh University scientist Tilo Kunath told BBC. “We had to dig further into this phenomenon.”

At present, Parkinson's disease is very difficult to diagnosis. Doctors rely on reported symptoms and an observational technique that was developed in the 1800s. But if Milne's nose is accurate, it means that people with Parkinson's might produce a signature odor, even at the early stages of the disease. If they can develop a test for the condition based on Milne's observations, they might be able to dramatically improve the accuracy of diagnosis. If they can do that, they might be able to test treatment options that could slow or even stop the development of the disease.

And that could make a huge difference in the lives of the hundreds of thousands of Americans who are living with Parkinson's in the U.S.