A nerve conduction study (NCS) is a medical diagnostic test measures how fast an electrical impulse moves through your nerve.

During the test, your nerve is stimulated, usually with electrode patches attached to your skin. Two electrodes are placed on the skin over your nerve. One electrode stimulates your nerve with a very mild electrical impulse, the other electrode records it. The resulting electrical activity is recorded by another electrode. This is repeated for each nerve being tested.

These tests may be performed by medical specialists such as clinical neurophysiologists, physical therapists, chiropractors, physiatrists (physical medicine and rehabilitation physicians), and neurologists who subspecialize in electrodiagnostic medicine.

NCS is often used along with an EMG to tell the difference between a nerve disorder and a muscle disorder. NCS detects a problem with the nerve.