Tried yandex but they don't have article about a smell from Parkinson's patients, but here's details, they are getting closer to the problem

http://www.dailymail.co.uk/news/article-3283727/The-grandmother-sniff-Parkinson-s-Special-skill-detect-crippling-condition-earlier-noticing-changes-way-person-smells-leads-pioneering-research.html