moondaughter,

I take your point about the response to an "insult". Not only will it vary from person to person, but the same person will respond differently at different times.

Regarding your forest fire analogy. It seems to me that, in contrast to Parkinson's, as soon as people see the signs of the fire they do something to put it out.

GerryW,

It's a long shot, but it's worth reading:
Can My Bird Make Me Sick?
Common Zoonotic Diseases in Pet Birds
By Alyson Kalhagen, About.com Guide
http://birds.about.com/od/birdhealth...icdiseases.htm
which gives details of the diseases you can catch from pet birds.

Given that you have an identical twin who doesn't have PD, I think you could do us a great service by creating a thread on yourself; starting by listing the things that you have done differently. It might be just the thing that gives us the crucial hint on where to look. It would also be useful to see if he has any symptoms of PD. For instance, does his side-to-side tap rate show any sign of slowness?

John