It seems to me that feelings of shame about Parkinson’s are based on a sense of responsibility for the condition you are in (or your inability to change it). However, there is a difference between having something and being responsible for that possession. For example, you had two eyes when you were born but you didn’t consciously choose to have two eyes. That part of yourself just is. The same with Parkinson’s; you didn’t choose it, nobody did. Therefore, if you judge yourself for having two eyes (or Parkinson’s disease), such a judgement is absurd because it judges nobody. Feelings of shame are not justified for such elements of thrownness.
Shame is usually felt in the context of other people and what they might be thinking of us. We can’t do much about the views of others, they are free to think what they like. You may have the juiciest, best tasting apple ever grown but when you offer it to somebody they can refuse to take it; some people just don’t like apples!
Shame can understandably lead us to try and hide our Parkinson’s in an attempt to confine and control our feelings. Telling others risks loosening that control, like releasing a kite on a windy day for all to see. It must be a personal choice whether to fly the kite. You may encounter positive, negative or indifferent responses. The opinion of others doesn’t have to dictate how you see yourself. The important thing is how you respond to their response. I found trying to hide my tremor exhausting and people noticed it anyway. I prefer to be honest and open about my Parkinson’s to remove any uncertainty in the people I meet. I think I’m able to do this because I know I’m free to react to their response in any way I want to.