Dr. Tilo Kunath told the BBC that's when he decided to put her to the test.
“We recruited six people with Parkinson's and six without,” he explained. "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. Her accuracy was 11 out of 12. We were quite impressed."
She was actually 12 for 12.
Joy insisted one of the people in the control group had the illness. Doctors told her he didn’t, but Kunath confirmed that eight months later, the man had been diagnosed with Parkinson's.
Scientists theorize people with early Parkinson's have changes in their skin leading to a change in smell.
Doctors hope they can devise a swab that would pick up the scent, and make diagnosing the disease an easier process.