A nerve conduction study (NCS) is a test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body.

Nerve conduction studies are mainly used for the evaluation of paresthesias (numbness, tingling, burning) and/or weakness of the arms and legs. It can be used to diagnose disorders of the peripheral nerves and muscles.


Normal body temperature must be maintained (low body temperature slows nerve conduction).


The nerve is stimulated, usually with surface electrodes, which are patch-like electrodes (similar to those used for ECG) placed on the skin over the nerve at various locations.

One electrode stimulates the nerve with a very mild electrical impulse.

The resulting electrical activity is recorded by the other electrodes. The distance between electrodes and the time it takes for electrical impulses to travel between electrodes are used to calculate the nerve conduction velocity.

Electromyography is the second part of this test and is often done within one week of the NCS.

How It Feels:

The test is not invasive, but can be a little painful due to the electrical shocks. However, the shocks are associated with such a low amount of electrical current that they are not dangerous to anyone.

There should be no residual discomfort once the test is finished.