A Nerve Conduction Study (NCS), also called a Nerve Conduction Velocity (NCV) test - is a measurement of the speed of conduction of an electrical impulse through a nerve. NCS can determine nerve damage and destruction. The Nerve Conduction Velocity (speed) is calculated by measuring the distance between electrodes and the time it takes for electrical impulses to travel between electrodes. The procedure helps to detect the presence, location, and extent of diseases that damage the nerves and muscles.