A nerve conduction study (NCS) --also called a nerve conduction velocity test (NCV)--is a measurement of the amount and speed of conduction of an electrical impulse through a nerve. NCS can determine nerve damage and destruction which cause the muscles to react in abnormal ways.
The test may be performed by a NCS technologist or a doctor. 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. The resulting electrical activity is recorded by another electrode. This is repeated for each nerve being tested. Learn more about NCS in the Health Library.
Both procedures help to detect the presence, location, and extent of diseases that damage the nerves and muscles.