WOW, those are tough questions. yes, i still have slight rigidity in my feet when on and worse when off which i expect to be forever, but who knows if the DBS will eliminate it?
i have no idea what the answer is to your 2nd question, increased lifespan was never mentioned when my neuro suggested it, i was told it might increase how long i can live independently which i was one reason i decided to do it. i think if you lived longer with a DBS on average that would be a well known fact. i want to live better, the longer is secondary to me.