Idea for a Clinical Trial:
It is difficult to set up a High Dose Thiamine (HDT—B1) Clinical Trail because dose is variable, unique and the protocol can take more than six months (added cost)—So how about a trial where People with Parkinson (PwP) who are successful on a HDT dose, be split into groups. One group taking their successful dose and a second taking only a placebo. Ok, introduces problems with researchers and subjects not knowing which group is which, but that should be still a doable.
To me, should be done with oral Thiamine HCL to reduce cost. I feel most will have Return of Symptoms within a month.
Their is little question in my mind that HDT works and all should try. I recommend Dap1948 's book and her Facebook Group.