Any published studies of the effectiveness of LDN (low dose naltrexone) in combating Parkinson's Disease?

There is quite a bit of anecdotal evidence that LDN can help those afflicted by a number of diseases including MS, Aids, and Crohn's Disease. (See for example the book "Up the Creek with a Paddle" by Mary Anne Boyle Bradley). I would like to doent any formal "double blind" clinical tests of LDN on Parkinson's. I have had PD for about 10 years and the standard drug regime is rapidly losing effectiveness. I am exploring the possibility of brain surgery called Deep Brain Stimulation but would be willing to try LDN. The main problem is to find a doctor who is willing to give me a prescription. Any help/advice on these matters is greatly appreciated. And many thanks in advance, Ron Wirick