Nerve Conduction Study

What is it?

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.

A related procedure that may be performed is electromyography (EMG). An EMG measures the electrical activity in muscles and is often performed at the same time as NCS. Both procedures help to detect the presence, location, and extent of diseases that damage the nerves and muscles.


Your doctor will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure. Generally, no fasting or sedation is required prior to the procedure. Normal body temperature must be maintained before and during the procedure, as low body temperature slows nerve conduction. Notify your doctor of all medications (prescribed and over-the-counter) and herbal supplements that you are taking. Dress in clothes that permit access to the area to be tested or that are easily removed. Stop using lotions or oils on your skin for a few days before your procedure. Based on your medical condition, your doctor may request other specific preparation - you will be advised if this is the case.


The outcome of the Nerve Conduction Study will be reported by a suitably qualified Neurologist and forwarded to your referring doctor over the course of 2-3 business days. Alarming, abnormal results will be phoned through to your GP and referring doctor at the soonest instance.


The voltage of the electrical pulses used during NCS is considered very low.

There may be risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.

Certain factors or conditions may interfere with the results of NVC test, such as damage to the spinal cord, severe pain before the test, and body temperature.

Tell your doctor if you have a cardiac defibrillator or pacemaker, as precautions may need to be taken.