WHAT IS IT?
This is a diagnostic study that
provides information about the nerve and muscles. It is
useful for evaluating conditions in which there is
compromise to the integrity of the nerves and muscles
(carpal tunnel syndrome, peripheral neuropathy, pinched
nerve, muscle disease, etc.). It consists of two parts:
nerve conduction study (NCS) and electromyogram (EMG).
For the NCS, the
doctor places small electrodes on your skin, and uses a
stimulator to deliver a very small electrical current to
your skin near nerves being tested, causing your nerves
to fire. The electrical signals produced by nerves and
muscles are recorded by the computer. The stimulator
only produces a very small shock that does not cause
damage to your body. Many different motor and sensory
nerves are typically evaluated.
For the EMG, a very small needle is inserted into various
muscles in the arm, leg, neck or back. This needle is
connected to a computer by a wire, which displays the
activity of the muscle being tested. There is no
electrical stimulation in this part of the study. In
many cases the examination will include areas far from
where you are having symptoms because nerves can be very
long. A clean new needle is used on each examination,
and the needle is thrown out after the examination is
complete. There is virtually no chance to catch any
diseases from having an EMG.
HOW DO I PREPARE FOR IT?
On the day of the
exam, do not use any lotions, moisturizers or powders
and wear loose clothing. Let the doctor know if you are
taking any blood thinners since the EMG portion of the
test involves insertion of a small needle into the
There may be some
discomfort in either part of the test, but most people
tolerate the test without difficulty.