A woman who says she can smell Parkinson's disease has prompted further research into whether people with the condition produce a particular odour.

Joy Milne, from Perth in Scotland, said she first noticed a change in her husband, Les, six years before he was diagnosed with the disease — a progressive neurological disorder with no known cause.

Mr Milne was diagnosed 20 years ago, and died in June this year at the age of 65.

"His smell changed and it seemed difficult to describe. It wasn't all of a sudden," Ms Milne told the BBC.

"It was very subtle — a musky smell."

She said she did not realise the connection of the smell to the condition until she joined the charity Parkinson's UK.

"When I was in a room with other people with Parkinson's, I realised they also had the smell," she said.

Ms Milne said she had a sensitive sense of smell, being able to detect things other people could not.

Edinburgh University tested out her claim, getting her to smell the shirts of 12 people — six people with the disease and six without — to see if she could identify the people with the disease.

She identified 11 out of the 12 correct, but was adamant one of the control subjects had the disease.

"According to him and according to us as well he didn't have Parkinson's," Edinburgh University researcher Dr Tilo Kunath said.

"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."

New study hopes to develop diagnostic test

As a result of this, Parkinson's UK is funding researchers in Edinburgh, Manchester and London to carry out a study to establish if people in the early stages of the disease emit a particular smell.

Researchers will examine 200 people with and without the disease from across the UK.

It is hoped a simple diagnostic test will be developed from the research.

There are no diagnostic tests for the disease, with people currently being diagnosed through specialist observation.

The disease, which also has no known cure, can leave people struggling to walk, speak and sleep.

Parkinson's disease affects approximately 80,000 Australians.