Violinist plays during his own brain surgery.

When Roger Frisch noticed hand tremors back in
2009, it was no small deal -- as a professional
violinist, steady hands are absolutely imperative
to his work. With shaking hands, Frisch -- who
had been a professional musician for 40 years --
could no longer draw the bow smoothly across
the strings of his instrument. He was diagnosed
with nervous disorder essential tremor .
The solution? Deep brain stimulation, to be
administered by brain surgeons at the Mayo Clinic
Neural Engineering Lab. This procedure involves
the implantation of what is known as a brain
pacemaker, which sends electrical impulses to
specific parts of the brain -- it is used to treat
such conditions as Parkinson's disease, major
depression, Tourette syndrome, tremors, and
chronic pain.
Although Frisch's tremors might be considered
relatively minor, for a concert violinist they would
have spelled the end of his career.
In order to find the brain region that was causing
the tremors, the surgeons had to insert electrodes
into his brain, stimulating various points. But,
because the tremor was so mild, the surgeons
would not have been able to tell if they were
hitting the optimum spot -- unless, that is, Frisch
was awake and helping.
It's actually par for the course for patients to be
conscious during brain surgery so that doctors
can monitor their condition, but Frisch's case
required something new: for him to be playing the
violin. The surgical team fitted bow with a three-
axis accelerometer, which allowed the team to
monitor Frisch's movements in real-time. When
they inserted the electrodes into his brain, they
were able to gauge whether or not the stimulation
was affecting the tremors.
The surgery was effective -- Frisch was once
again playing with the Minnesota Orchestra just
three weeks later. He can turn the pacemaker on
using a controller, allowing him to play just as
smoothly as he could before the tremors. The
video below was uploaded by the Mayo Clinic in
April of this year.