Thank you for your thoughts. Yes, I'm going to ask my neurologist whether PD can be brought on by a blow to the head. I've read that it can, but years after the blow. I'm hoping that I'm blowing all of this out of proportion and it will truly go away.

Interesting that your jerking starts from the diaphragm. That happens to me too and those jerks feel very different (in a way that I cannot explain) from the ones happening in other parts of my body.

A little bit of me is sensitive to head blows because my brother developed epilepsy after he hit his head on bricks. The doctors said that the brain damage causing the epilepsy was always there, but it took a blow to the head to start the seizure activity. He's now had seizures for 35 years. So sad for him.