A CSI actor was diagnosed with an illness similar to Parkinsons that required him to have surgery to implant a pacemaker to reduce his symptoms. He had surgery yesterday morning, and the operation was transmitted live on the internet. They used Twitter, Vine and Instagram.
Remember that the brain doesn’t have sensory nerves. So during brain surgery, doctors want to anesthetize the scalp, but once they’re deep to the skull’s cranium, it’s not unusual to have patients awake so the doctors can immediately tell if they are in the right place in the brain and/or if the surgery is working. They do this in brain surgery for epilepsy too.
In this case, you can see the surgery was successful. Tremors he had been having were greatly reduced, and he could play the guitar.
References below have video links of patient awake during surgery, playing the guitar and doing tests.