London: A 65-year-old Scottish woman has a unique ability that can revolutionise the way Parkinson's is diagnosed: she can sniff out the debilitating disease.
Joy Milne, from Perth, Scotland first detected the odour on her husband, who was diagnosed with Parkinson's disease at the age of 45 and died in June this year.
Joy noticed something had changed with her husband six years before he was diagnosed with the disease.
"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," she said.
Joy only linked this odour to Parkinson's after joining the charity Parkinson's UK and meeting people with the same distinct odour, 'BBC News' reported.
Scientists were intrigued when she mentioned this at a talk. They decided to test her and she was very accurate.
"The first time we tested Joy we recruited six people with Parkinson's and six without," said Dr Tilo Kunath, a Parkinson's UK fellow at Edinburgh University.
"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," said Kunath.
"Her accuracy was 11 out of 12. We were quite impressed," he said.
However, eight months later the twelfth person told researchers that he also 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," Kunath said.
Changes in the skin of people with early Parkinson's produces a particular odour linked to the condition, scientists believe.
They hope to find the molecular signature responsible for the odour and then develop a simple test such as wiping a person's forehead with a swab.
Parkinson's disease can leave people struggling to walk, speak and sleep. There is no cure and no definitive diagnostic test.