Former international violinist Naomi Elishuv gave up playing 20 years ago when she developed essential tremor. Israeli doctors fitted a Deep Brain Stimulation electrode into her damaged brain under local anesthetic, and whilst Naomi played the violin, they guided it to the correct spot.
http://www.jpost.com/Israel-News/Health/Former-violinist-with-tremor-regains-ability-to-play-while-performing-during-brain-surgery-374941 https://www.youtube.com/watch?v=tWHA7q4IQmg