Nerve Conduction Study
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.
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.
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.
Diseases or conditions that may be evaluated with NCS include, but are not limited to, the following
- Guillain-Barré syndrome. A condition in which the body’s immune system attacks part of the peripheral nervous system. The first symptoms may include weakness or tingling sensations in the legs.
- Carpal tunnel syndrome. A condition in which the median nerve, which runs from the forearm into the hand, becomes pressed or squeezed at the wrist by enlarged tendons or ligaments. This results in pain and numbness in the fingers.
Charcot-Marie-Tooth disease. A hereditary neurological condition that affects both the motor and sensory nerves. One characteristic is weakness of the foot and lower leg muscles.
- Herniated disk disease
- Chronic inflammatory polyneuropathy and neuropathy. These are conditions resulting from diabetes or alcoholism.
- Sciatic nerve problems
- Pinched nerves
- Peripheral nerve injury
Nerve conduction studies may also be performed to identify the cause of symptoms such as numbness, tingling, and continuous pain.