I had never heard before that exposure to agents orange increased the probability of getting Parkinson's. That may well be true. It occurs to me that if we could bring to bear the political clout of some of the other large organizations such as the veteran's groups because of the connection you just reference. Also the AARP as Parkinson's primarily affects the elderly or NOW because of the ludicrous contention that women might choose to have an abortion solely to provide fetal tissue for research. If anyone has any strong connections with those groups please consider exploring the possibilities. With respect to "is there anything else you can do?"the answer is make an appointment to see your Senator personally. Letters are an important part of the persuading process but actually visits seem to be the best closer.