Nerve Conduction Studies (NCS)

What is a nerve conduction study?

Nerve conduction study (NCS) is a measurement of the speed of conduction of an electrical impulse through a nerve. NCS can determine nerve damage and destruction.

During the test, the nerve is stimulated, usually with surface electrode patches attached to the skin. Two electrodes are placed on the skin over the nerve. One electrode stimulates the nerve with a very mild electrical impulse and the other electrode records it. This is repeated for each nerve being tested.

The nerve conduction velocity (speed) is then calculated by measuring the distance between electrodes and the time it takes for electrical impulses to travel between electrodes.

How to prepare before your test

We ask that you wear loose fitting clothing; shorts or a skirt if you are having your lower extremities tested, and short sleeve or sleeveless clothing for upper extremities.

Please do not use any lotions, oils or powders on the skin that is to be tested.


These pages are intended to provide basic information about neurological procedures to the general public. It is not intended to, nor does it, constitute medical advice, and readers are warned against changing medical schedules and activities without first consulting a physician.