Earlier quoted context omitted.
Dopamine is to help control symptoms, not to slow development of the disease. There is no use for dopamine treatment in an early diagnosis that precedes meaningful symptoms. Lifestyle changes, on the other hand, mostly meaning exercise, significantly and reliably slow the onset and development of symptoms.
What does early intervention look like for Parkinson’s besides lifestyle changes?
We have talked to many different Parkinson's experts around the world, and I think at this point the only thing she seems to think really makes a difference is lots of exercise. She completed halting any evidence of the progression of the disease for about 5 years with exercise, but it will not last forever.
So completely serious, if you get flagged for Parkinsons, and start getting in amazing shape, you have a good chance of really helping yourself get more good years.
Fingers crossed for ongoing research to finally find some way to stop or reverse the damage in another way! (not medical advice)