DBS usually brings on the next set of symptoms that would have appeared anyway. In my case it was tremor, which was controlled by the DBS. i was stable from 2001 til 2008 when my balance began to be affected. I put this down to the natural progression of the disease.
I could reprogram, but its not that big of a pain in the *** (literally!) AT some point I willl have to go back on meds instead of the "as needed" once or twice a month for break-through termor. I will put off reprogramming as long as possible. SUch is life!!

Charlie