Nerve Conduction Study


A nerve conduction study (NCS) is a test that measures the speed and strength of electrical activity in a nerve. The test can gather information about the structure and function of both muscle and nerve.

Electromyogram of Shoulder—Used in Conjunction with Nerve Conduction Study

Electromyogram EMG
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Reasons for Test    TOP

A NCS is most often done to:

  • Help diagnose the cause of pain, cramping, numbness, or weakness
  • Determine if nerves are working properly
  • Identify the difference between muscle and nerve disorders
  • Monitor if a nerve is recovering from injury

Possible Complications    TOP

There are no major complications associated with this test.

What to Expect    TOP

Prior to Test

Before your procedure:

  • Make sure you talk to your doctor about the medications you are taking.
  • If you have myasthenia gravis, ask if you should take any medication before the test.
  • If directed to, avoid cigarettes, coffee, tea, and soft drinks for 2-3 hours before the test.
  • Shower the day of your test. Do not use any creams, moisturizers, or powders on your skin.

Description of Test

Your skin will be cleaned. Electrodes will be taped to the skin along the nerves that are being studied. A small stimulus will be used to apply an electric current that causes the nerves to activate. The electrodes will measure the current that travels down the nerve pathway. The current will be slower and weaker if your nerve is damaged. Your doctor will use the stimulus at different places to determine the specific site of the damage.

Nerve conduction studies are often done along with electromyography (EMG).

After Test    TOP

You will be able to resume your daily activities after the test is complete.

How Long Will It Take?    TOP

About 30-90 minutes

Will It Hurt?    TOP

You will feel mild discomfort from the shocks. It should not be very painful.

Results    TOP

Your doctor will study the information from the test. A report should be ready within a few days.

Call Your Doctor    TOP

Call your doctor if you have any questions or concerns following the test.

In case of an emergency, call for medical help right away.


American Chronic Pain Association
National Institute of Neurological Disorders and Stroke


Canadian Neurological Sciences Federation
Chronic Pain Association of Canada


Electrodiagnostic testing. American Academy of Orthopaedic Surgeons website. Available at:
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Updated October 2007. Accessed August 6, 2013.
Specialized nerve tests: EMG, NCV, and SSEP. North American Spine Society website. Available at:
...(Click grey area to select URL)
Updated June 16, 2011. Accessed August 6, 2013.
Spinal diagnostics: nerve conduction studies. Cedars-Sinai website. Available at:
...(Click grey area to select URL)
Accessed August 6, 2013.
Last reviewed August 2013 by Rimas Lukas, MD; Michael Woods, MD
Last Updated: 5/11/2013