Then I think you are likely to be disappointed. The preliminary clinical trial which subsequent studies are based on was pretty low quality. To memory, its flawed by low participant numbers, high loss to follow-up, only modest improvements to moderate stutterers (something like 10-15% improvement) without significant benefit seen in the 2 severe stutterers in the study etc. The study participants are going to be blinded anyway and even if they knew it would be anecdotal evidence. Personally I think the dopamine hypothesis is wrong and this is eminence based science..