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
|Copyright © Nucleus Medical Media, Inc.
Reasons for Test
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
There are no major complications associated with this test.
What to Expect
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. Stimulus will be used at different places to determine the specific site of the damage.
You will be able to resume your daily activities after the test is complete.
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.
Your doctor will study the information 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 following the test.
In case of an emergency, call for emergency medical services 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:
Updated October 2007. Accessed May 11, 2016.
Specialized nerve tests: EMG, NCV, and SSEP. North American Spine Society website. Available at:
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.