Just when does something - a process - actually begin? When you eat an apple at what point does apple stop being apple and start being you? And when a chronic disease process eats you when do you stop being you and start becoming a manifestation of the process?
Texts on PD state that by the time any symptoms become noticable a huge portion - ~ 80% or thereabouts, of the dopamine producing cells in the substancia nigra portion of the brain have packed their bags and checked out - so in clinical terms, this disease process is a real futher-mucker for most.
My first clue that something was rotten in my inner Denmark was a very tentative, almost shy pinky tremor on the left hand. As a keyboard musician I probably took note of this earlier than most, hyper aware of sensation and feedback from the perspective of a musicians hand. Thought not-too-much of it for a while....
After a few months it became more regularly present, usually only when at the keyboard. Made mention of it at a regular physical - couldn't produce the tremor on demand and, at that initial point, we both dismissed it as nothing of concern. But next day, there was my little friend, back in the pinky happily waving and dancing in the wind..... the battle was on