Carl R. Darnall Army Medical Center - Health Library

Nerve Conduction Study

Definition

A nerve conduction study (NCS) is a test that measures the speed and strength of electrical activity in a nerve. The test can gather details 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 ^

A NCS is most often done to:

  • Find out the cause of pain, cramping, numbness, or weakness
  • Find out if nerves are working the right way
  • Tell apart muscle and nerve problems
  • Check if a nerve is recovering from injury

Possible Complications ^

There are no major problems from this test.

What to Expect ^

Prior to Test

Before your NCS:

  • Make sure you talk to your doctor about the medicines you are taking..
  • If your doctor tells you, do not smoke cigarettes or drink 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. It will cause 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. Stimulus will be used at different places to find the site of the damage.

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

After Test

You will be able to go back to your daily activities after the test is done.

How Long Will It Take?

About 30-90 minutes

Will It Hurt?

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

Results

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

Call Your Doctor ^

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

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

RESOURCES:

American Chronic Pain Association
http://www.theacpa.org

National Institute of Neurological Disorders and Stroke
http://www.ninds.nih.gov

CANADIAN RESOURCES:

Canadian Neurological Sciences Federation
http://www.cnsfederation.org

Chronic Pain Association of Canada
http://www.chronicpaincanada.com

REFERENCES:

Electrodiagnostic testing. American Academy of Orthopaedic Surgeons website. Available at: http://orthoinfo.aaos.org/topic.cfm?topic=A00270. Updated October 2007. Accessed May 11, 2016.

Specialized nerve tests: EMG, NCV, and SSEP. North American Spine Society website. Available at: http://www.knowyourback.org/Pages/Treatments/AssessmentTools/SpecializedNerveTests.aspx. Updated June 16, 2011. Accessed May 11, 2016.

Spinal diagnostics: nerve conduction studies. Cedars-Sinai website. Available at: http://www.cedars-sinai.edu/Patients/Programs-and-Services/Spine-Center/Conditions-and-Treatments/Diagnostic-Studies/Spinal-Diagnostics-Nerve-Conduction-Studies.aspx. Accessed May 11, 2016.

Last reviewed June 2018 by EBSCO Medical Review Board Rimas Lukas, MD  Last Updated: 6/12/2018