A VNS, or those similar is a big deal and that is something you really need to think about before you decide that route. I understand it may be what is right for you, but the risks are incredible.... it is brain surgery. My father had one done for Parkinson's. Unfortunately, he had a stroke a couple days before it was to be turned on. As a family we discussed the risks, and a stroke was a possibility and went for it regardless, but now I think, my father whom is bedridden and will not last the summer probably, I would love to be able to talk to again...I would undo that risk. I think about this one all the time. The risks we take, anything can happen and it is a gamble, but we need to really think about that before we leap.
I wish you the best, I know this isnt easy, I am spending a lot of time playing med roulette right now. Take care