Joy Milne's husband, Les, died in June, aged 65.
He worked as a consultant anaesthetist before being diagnosed with Parkinson's at the age of 45.
One in 500 people in the UK has Parkinson's - that is 127,000 across Britain.It can leave people struggling to walk, speak and sleep. There is no cure and no definitive diagnostic test.
Joy noticed something had changed with her husband long before he was diagnosed - six years before.
She says: "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."
Joy only linked this odour to Parkinson's after joining the charity Parkinson's UK and meeting people with the same distinct odor.
By complete chance she mentioned this to scientists at a talk. They were intrigued.
Edinburgh University decided to test her - and she was very accurate.
As reported on BBC News on the 22nd of October, 2015.
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