Laura,

Thanks for your offer to promote the survey. I'll be grateful.The more people we have, the more chance of finding something significant. People in this forum know the context so I've pointed you directly at the survey. People outside will not have this background. So, I suggest you point them at the home page of my web site:
http://www.parkinsonsmeasurement.webatu.com
This gives the required context.(It's still early days for the site, so there's little in it other than the survey and the online tools I've written.) It is easy to navigate to the survey from there.

Your idea of looking at demographics is good. I'll post on this later.

We now have 27 replies to the survey.

John