Nerves control the muscles in the body using electrical impulses and these impulses make the muscles react in specific ways. Nerve and muscle disorders cause the muscles to react in abnormal ways.

Why it is performed
Nerve conduction studies are performed to:

• Detect and evaluate damage to the peripheral nervous system, which includes all the nerves that lead away from the brain and spinal cord and the smaller nerves that branch out from those nerves. Nerve conduction studies are often used to help diagnose  nerve disorders, such as carpal tunnel syndrome or Guillain-Barre syndrome.
• Identify the location of abnormal sensations, such as numbness, tingling or pain.

Nerve conduction studies can help diagnose a condition called post-polio syndrome that may develop months to years after a tingling or pain.

How it is performed
In this test, several flat metal disc electrodes are attached to your skin with tape or a special paste. A shock-emitting electrode is placed directly over the nerve to be studied and a recording electrode is placed over the muscles supplied by that nerve. Repeated, brief electrical pulses are administered to the nerve and the time it takes for the muscle to contract in response to the electrical pulse is recorded. The speed of the response is called the conduction velocity.

The corresponding nerves on the other side of the body may be studied for comparison. When the testing is completed, the electrodes are removed.

Nerve conduction testing may take from 15 minutes - 1 hour or more, depending upon how many areas of the body are studied.

How it feels
With the nerve conduction studies, the patient feels a brief, burning pain, a tingling sensation and a twitching of the muscle each time the electrical pulse is applied. If feels similar to the kind of tingling you feel when you rub your feet on the carpet and then touch a metal object. The testing can be quite uncomfortable and makes some people nervous. Keep in mind a very low-voltage electrical current is used and each electrical pulse is very brief.

Risks
There are no risks associated with nerve conduction studies. Nothing is inserted into the skin and there is no risk of infection. The voltage of electrical pulses is not high enough to cause an injury or permanent damage.