Hi Rosie,
Wow! You're going to be the real Bionic Woman! I recently came across a reference to this, because I have 2 friends with Parkinson's, and they were discussing this procedure which, it seems, is usually done for that and other ailments involving major dystonia. This site is quite good:
http://www.parkinsonsappeal.com/index.html
and I would also put it into Google Images search - often you get more info from seeing the pix (I've already done this, there's scores of stuff to look at) .
Also, post on the Parkinson's forums - the one here is very good, I'm sure they'll direct you to more info anyway.
It sounds very radical - hey, anything involving opening the skull must be, but it looks similar *in mechanics* to a spinal cord stimulation procedure...but I need to read up on it more, you know, websites with personal stories, to see how people actually cope with it in the real world.
I suppose you have to weigh the problems you have now (now being the status quo) with the benefits to be gained and the risk factor - only you can decide that...but you sound very upbeat about it.
And yes, very scary idea, but I must say that the websites I've looked at are very positive.
You are so gutsy, I know you'll make the right choice for yourself
Take care, good to see you back online,
all the best!