Brain surgery is hard, but being awake while it is done to you presumably isn't exactly easy either. So a standing ovation to Roger Frisch of the Minnesota Orchestra, who not only stayed alert while an electrode was inserted deep in his thalamus, but played the violin throughout the process.
Deep brain stimulation works by having electrodes planted in the brain send out signals at specific frequencies. It is not really understood why these help, let alone why certain frequencies work and others make things worse, but for some patients with Parkinson's Disease, dystonia or depression the pulses make a big difference to their quality of life.
Although there is evidence for benefits from electrode insertion earlier than is usually done for patients with degenerative diseases, the tremors Frisch was experiencing were so small that in any other line of work they would be ignored. However, as a concert violinist the shakes prevented him from doing his job.
The major challenge in implanting the electrodes for deep brain stimulation is that the electrodes must be placed with extraordinary precision. Even for those conditions where the operation is common the electrodes sometimes get fractionally misplaced, and in Frisch's case the tremors were so slight that identifying the source was even harder.
The surgeons at the Mayo clinic where the electrodes were implanted decided they needed Frisch awake and performing during the operation so they could see when they had reached the part of the brain causing the tremors. Engineer Kevin Bennet designed a violin Frisch could play during the operation, including an accelerometer that allowed the medical team to detect whether the slightest tremors were occurring.
As can be seen in the video below, the operation was a major success and Frisch has able to continue his career, as long as he sets the pacemaker controlling the electrodes.
Studies in recent years have shown that playing music to patients undergoing surgery improves their prospects for recovery, however, it is doubtful a sufficient sample size could be produced to measure the effects of the patient playing the music themselves.