Parkinson's is the world's fastest-growing neurological condition, causing difficulties in walking, talking and daily life, and currently with no cure. Early diagnosis tests and treatments are still in their infancy, and it is a difficult condition to detect, but one woman from Scotland has, amazingly, been found to be able to smell the disease in patients, years before symptoms appear.

Nurse Joy Milne first realized her husband had the condition when she noticed a distinct new musty odor from her partner, 12 years before he was diagnosed. Now she is working with researchers from Manchester University in the United Kingdom to produce a chemical test for the disease, which has shown 95 percent diagnostic accuracy under laboratory conditions. The hope that one day there might be a fast and accurate diagnosis for the condition could be a game-changer for millions of people around the world, and all inspired by one woman's nose.

The Manchester test uses a small cotton bud that is run down the back of a person's neck. Researchers then analyze the sample to identify molecules associated with the disease. Just as with cancer, heart disease and diabetes, early diagnosis can lead to far more effective treatments and outcomes for patients. For the vast majority of Parkinson's patients, however, it comes far too late, and the degree of neurological damage that has already occurred can be debilitating. Diagnosis currently relies on a patient's symptoms, as well as looking into their medical history, a far cry from being an early preventative measure. Although this new test is still in the early stages of research, scientists are excited at the prospect of being able to roll out a single simple procedure for the disease.

Joy Milne's acute sense of smell was the trigger for this potential breakthrough. Her ability to sense chemical changes in skin oil in people with Parkinson's has been tested and proven under laboratory conditions. Milne was asked to smell t-shirts worn by a selection of people, some with Parkinson's and some without. She correctly identified those currently with the disease, but also identified one other person from the group without the disease. This confused scientists, who put the result down as a false positive result, but 8 months later that individual developed the condition and was officially diagnosed. The power of her smell in being able to recognize subtle molecular signatures many months before symptoms appear is a huge step forward in understanding of the disease.

Meanwhile, while researchers are busy developing a Parkinson's test based on her natural gift, Joy is working on other international projects to see if she can smell certain types of diseases such as cancer or tuberculosis. Her sense of smell is so acute that she is forced to shop very early in the mornings or late at night, to avoid the overpowering smell of people's perfumes. Similarly, aisles with lots of chemical products are areas she cannot tolerate for long.

Day-to-day living with such an ability has profound consequences, and she has said that sometimes in public places, she is able to smell people who have Parkinson's disease as they pass. Medical ethicists have advised her that she is not allowed to tell them, which is understandable as many would be unlikely to believe her as a passing stranger anyway. But the medically-approved tests she helps create could change the world for all who pass her by.

Barry He is a London-based columnist for China Daily