EMG / NCT / NCS
What is a Nerve Conduction Study (NCS) or Nerve Conduction Test (NST) ?
- A nerve conduction test — measures how fast an electrical impulse moves through your nerve. It can identify nerve damage.
- During the test, your nerve is stimulated, with electrode patches attached to your skin. 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.
- The speed is then calculated by measuring the distance between electrodes and the time it takes for electrical impulses to travel between electrodes.
- The nerve conduction test helps find the presence, location, and extent of diseases that damage the nerves and muscles.
- The voltage of the electrical pulses used during an NCS is considered very low.
- Risks depend on your specific medical condition. Be sure to discuss any concerns with your healthcare provider before the procedure.
- Certain factors or conditions may interfere with the results of NCS tests. This includes damage to the spinal cord, severe pain before the test, and body temperature.
- Tell your healthcare provider if you have a cardiac defibrillator or pacemaker, as
precautions may need to be taken.
How do I get ready for an NCS?
- You will be asked to sign this consent form
- Dress in clothes that allow 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.
What happens during the NCS?
- You will be asked to remove any clothing, jewelry, hairpins, eyeglasses, hearing aids, or other metal objects that may interfere with the procedure.
- If you are asked to remove clothing, you will be given a gown to wear.
- You will be asked to lie down for the test.
- Dr. Yong Tsai will locate the nerve(s) to be studied.
- Medical assistant will attach a recording electrode to the skin over your nerve, using a special paste. He or she will then place a stimulating electrode away from the recording electrode, at a known distance.
- A mild and brief electrical shock, given through the stimulating electrode, will stimulate your nerve.
- You may experience minor discomfort for a few seconds.
- The stimulation of the nerve and the response will be displayed on a monitor.
What happens after an NCS?
- The paste used to attach the electrodes will be removed from your skin.
- After the test, you may return to your previous activities, unless Dr. Tsai advises you differently. You may be instructed to avoid strenuous activities for the rest of the day.