My theory is that PD affects the things that we can learn to do without thinking - or do automatically such as walking or speaking. That is why things that are a little out of the ordinary can sometimes be unaffected. Hence the term kinesia paradoxica.

Some commentators have theorized that it is just the limbic system kicking in during a stressful circumstance, but I don’t believe that this theory fits the profile.

In addition to the video of Michael J. Fox skating, there are also videos of the fellow in Holland whose gait difficulties do not permit him to walk, but can ride a bike like a pro and the American who could not walk on his feet but who was fine walking on his hands.

I have heard stories about a man who fell in his kitchen until he painted stairs on the kitchen floor. And I believe the same mechanism is the basis for the Lee Silverman method of “Talking Big” and “Moving Big”.

Clyde