A doctor performs a nerve conduction test by adhering two electrode patches to the skin above the nerve and sending an electrical impulse through one of the electrodes to stimulate the nerve, explains Johns Hopkins Medicine. The second electrode records the electrical activity that occurs. The data allows the doctor to determine the velocity at which the nerve transmits electrical signals. The doctor repeats this process for each nerve under examination.
During a nerve conduction test, the patient must remove any clothing, accessories or medical devices that may interfere with the equipment used to perform the study, notes Johns Hopkins Medicine. Although the voltage applied through the electrode patches is very low, the patient may experience a small amount of discomfort. This discomfort usually subsides within a few seconds. As the procedure continues, the recorded data appears on a screen as a series of waves representing electrical activity through the nerves.
Doctors commonly perform nerve conduction studies alongside electromyographies to determine whether a patient's symptoms are due to a nerve or a muscle disorder, reports Johns Hopkins Medicine. Nerve conduction studies test whether the nerves transmit signals at a normal rate, while electromyographies test how well the muscles perform in response to messages from the nerves. Examples of conditions nerve conduction studies can help diagnose include carpal tunnel syndrome, peripheral nerve injuries, Guillain-Barré syndrome, herniated discs and inflammatory polyneuropathy.