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Nerve Conduction Study

  • Cynthia M. Johnson, MA
Publication Type:


Nerve Conduction Study


A nerve conduction study (NCS) measures the speed and strength of electrical activity in a nerve. The test can gather details about the structure and function of muscles and nerves.

Electromyogram of Shoulder—Used with a Nerve Conduction Study

Electromyogram EMG EMGNULLjpgElectromyogram EMGNULL\\hgfiler01a\intellect\images\Electromyogram_EMG.jpgNULL47NULL2008-01-294002266893_203693Copyright © Nucleus Medical Media, Inc.

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

The care team may meet with you to talk about:

  • Any allergies you may have
  • Current medicines, herbs, and supplements that you take and whether you need to stop taking them before the test
  • Whether you need to avoid smoking, food, and certain drinks for 2 to 3 hours before the test
  • Avoiding using any creams, moisturizers, or powders on your skin before the test

Description of Test

The skin will be cleaned. Electrodes will be taped to the skin along the nerves that are being studied. One electrode will stimulate the nerve with a mild electrical impulse. 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 the nerve is damaged. An electrical impulse will be used at different places to find the site of any damage.

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

How Long Will It Take?

About 30 to 90 minutes

Will It Hurt?

The test areas may be sore. This will go away in an hour or 2.


The 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.

If you think you have an emergency, call for medical help right away.





  • Electrodiagnostic testing. American Academy of Orthopaedic Surgeons website. Available at:
  • Nerve conduction studies. Johns Hopkins website. Available at:
  • Peripheral neuropathy. EBSCO DynaMed website. Available at:
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.