Nerve conduction studies are used to determine how well and how quickly the nerves send electrical signals; these studies are sometimes used to discover damage to the nervous system, such as when a patient exhibits symptoms of Guillain-Barre syndrome or carpal tunnel syndrome, according to WebMD. A nerve conduction study finds damage throughout the peripheral nervous system, which includes nerves that lead away from the spinal cord and brain and the smaller nerves branched out from those nerves.
During the nerve conduction test, the suspected affected nerve is stimulated, typically the use of electrical impulses delivered through electrodes that are attached to the skin directly above the nerve being tested. Another electrode records the electrical activity. The speed of nerve conduction is calculated to determine nerve destruction and damage, according to Hopkins Medicine.
The speed of conduction is directly related to the diameter of the nerve and the degree of the sheath that insulates the nerves, which are known as myelin. Normal nerves transmit stronger, faster signals than those that are damaged by disease or injury.
Other reasons for nerve conduction studies include diagnosing Charcot-Marie-Tooth disease, herniated disk disease, sciatic nerve problems, chronic inflammatory neuropathy or polyneuropathy, peripheral nerve injuries and pinched nerves, as noted by Hopkins Medicine.