Nerve Conduction Velocity

In performing this test, the nerve is electrically stimulated, and the electrical impulse travels through the nerve pathway and the stimulus is measured. Surface patch electrodes are used similar to those used for an electrocardiogram. They are placed on the skin over the nerve at various locations. The first electrode stimulates the nerve with a very gentle electrical impulse. The resulting electrical activity is recorded by the other electrodes. The distance between the electrodes and the time it takes for electrical impulse to travel between electrodes is used to calculate the nerve conduction velocity. If the speed is decreased , the transmission will indicate nerve disease. A nerve conduction velocity test is often performed at the same time as an electromyogram or EMG in order to exclude or detect muscle conditions.

When is a nerve conduction velocity test ordered?

A health care professional might be prompted to order a nerve conduction velocity test when a patient exhibits symptoms such as: numbness, tingling and/or burning sensations. An NCV can be used to detect nerve disorders, such as mononeuritis multiplex and peripheral neuropathy. These are conditions where the nerves are affected by mechanical compression injuries, such as carpal tunnel syndrome and compression neuropathy. A normal body temperature must be maintained during an NCV, because low body temperatures will slow nerve conduction.