Just speculating, but...
We all have experienced the shrill sound of feedback from a stage sound system but may not know the cause. It occurs when a microphone picks up the sound from its own speaker, amplifies it and puts it out through the same speaker to the same microphone which then picks it up.... and on and on.

(BTW, I am going to start using the word "distress" for the psychological effect to seperate it from things like "oxidative stress" etc.)

So, suppose I am hypersensitive to distress. I find that I am going "off" in a restaurant. I am going to experience distress, right? That is going to negatively impact my "off". Which is going to increase my distress. Which is... etc.

Had I been sitting home in a non-stressful environment, I suspect that the experience would have been quite different.

Now, I did not react this way, say, ten years ago. So, if this is a true factor then it comes on as PD advances. Or, perhaps, it has been there all along but worsens or some dampening feature fails.

It might just be an inconvenient symptom, but I don't think so. We know enough to understand that stress of all sorts is destructive when chronic.

Also, no one has ever explained the cause of "freezing". In myself I have noticed that distress is linked to freezing. If the feedback effect is considered, it would seem plausible that my system quickly goes into a catatonic state as the feedback loop amplifies the distress. After all, trying harder doesn't do it. In fact it makes it worse. Relaxing helps, however.

Anyone have thoughts on this one?