I personally don't think it would be a waste of time after 12 years, especially if he goes to a different neuro. He may not learn anything new, but what if he did and he could be rid of the beast.

I'm also idiopathic, and it's coming up on two years since I last saw my neuro and gave up. I'm contemplating giving it another go, either with a new neuro (maybe one at Hopkins), or a completely different kind of doc.