NCS and EMG are tests used to measure nerve and muscle function. In most cases the NCS is done first, with the EMG to follow.

Nerve Conduction Study (NCS)

A nerve conduction study depicts whether the body’s electrical signals are appropriately traveling to a nerve. Reasons to have a nerve conduction study include any/all of the following symptoms in your neck, arms, legs and/or back:

  • Numbness
  • Tingling
  • Pain
  • Weakness
  • Muscle cramping
  • Twitching

This test is done to establish why you are having these symptoms and will help to find out if you have damage to your muscles or nerves. It is a simple test that applies small electrical shocks to the nerve, causing a mild, tingling feeling, and then records the nerve’s response. This is done by using a very low-voltage electrical current to stimulate the nerves for less than a split second each time. Immediately after the test is done, a report is generated with your results.

Electromyography (EMG)

Electromyography measures electrical activity in your muscles. Unlike the NCS, no electrical currents are applied. To assess the muscle function, a fine needle electrode is placed under your skin into the muscle being tested. The electrode on the needle picks up the electrical activity given off by your muscles and then generates a report with your results.