Reflections: Mine Is Longer than Yours: Reporting & Essays: The New Yorker:
During the operation, your head is screwed into a metal frame and the frame is screwed into the operating table. My surgery lasted nine hours, and for most of it I had to be awake, so that the doctors could test the connection, like asking somebody to go upstairs and see if the light in the bedroom comes back on while you fiddle with the circuit-breaker box in the basement. It’s not fun, but it doesn’t hurt (your brain has no nerve endings for pain), and everything except the operation itself is sort of fun. Immediately after surgery, all the symptoms of Parkinson’s disappear—even though the batteries aren’t turned on for a month. The very process of implanting the wires mimics the effect of the electricity from the batteries. Over the next two or three weeks, the symptoms return. Then, when the batteries are turned on, they disappear or are reduced again. These results are instantaneous, though they vary from patient to patient, and it takes up to a year of visits, every month or so, to get the adjustment right.