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.
Nerve conduction studies are often done along with electromyography
Electromyogram of Shoulder—Used in Conjunction with Nerve Conduction Study
Reasons for Test
NCS is most often done to:
- Aid in diagnosing the cause of pain, cramping, numbness, or weakness
- Determine if nerves are working properly
- Distinguish between muscle and nerve disorders
- Monitor if a nerve is recovering from injury
What to Expect
Prior to Test
Leading up to your procedure:
- Make sure you talk to your doctor about the medicines you are taking.
- If you have myasthenia gravis, ask if you should take any medicine 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.
- Wear comfortable clothing, but expect to change into a hospital gown.
Description of Test
Your skin will be cleaned. Electrodes will be taped to the skin along the nerves that are being studied. Your doctor will use a small stimulus to apply an electric current that causes the nerves to activate. The electrodes will measure the current that travels down the nerve pathway. If your nerve is damaged, the current will be slower and weaker. Your doctor will use the stimulus at various places to determine the specific site of the damage.
Once the test is complete, you will be able to resume your daily activities.
How Long Will It Take?
About 30-90 minutes
Will It Hurt?
You will feel mild discomfort from the shocks. It should not be painful.
Your doctor will analyze the data from the test. A report should be available within a few days.
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: http://orthoinfo.aaos.org/fact/thr_report.cfm?Thread_ID=356&topcategory=General%20Information. Accessed April 19, 2007.
Electromyogram and nerve conduction study. North American Spine Society website. Available at: http://www.spine.org/articles/emg_test.cfm. Accessed April 19, 2007.
Electromyography (EMG) and nerve conduction velocity (NCV) tests. Penn State website. Available at: http://www.hmc.psu.edu/healthinfo/e/emg.htm. Accessed April 19, 2007.
Last reviewed November 2009 by
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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