Nerve Conduction StudyEn Español (Spanish Version)
A nerve conduction study (NCS) is an electrodiagnostic test that measures the speed and degree of electrical activity in a nerve to determine if it is functioning normally. It can gather information about the structural integrity and function of both muscle and nerve.
Electrodiagnostic tests are used to look for problems with nerves and muscles. Nerve conduction studies are often performed along with electromyograms, which are another type of test that analyze the electrical activity in your muscles.
Electromyogram of Shoulder—Used in Conjunction with Nerve Conduction Study
© 2008 Nucleus Medical Art, Inc.
Parts of the Body Involved
- Muscles, usually in the arms or legs
- Nerves ( sensory, motor, and mixed nerves)
Reasons for Procedure
Nerve conduction studies can be performed for a variety of reasons, including:
- Radiculopathy (pain that radiates from the neck or back, to localize site of compression)
- Nerve damage from herniated discs
- Peripheral neuropathy (damage to the longest nerves)
- Focal neuropathy (damage to a single nerve; includes carpal tunnel syndrome)
- Myopathy (muscle disease)
- Diseases of neuromuscular junction (Myasthenia gravis)
- Symptoms indicative of nerve damage, including numbness, weakness, or tingling
- The status of repair and recovery from injury can be assessed
- Differentiation between acute and chronic processes
- Differentiation between acquired and inherited processes
- Differentiation between focal or a diffuse disease process (mononeuropathy or polyneuropathy)
- Assist in narrowing down a differential diagnosis
- Provides prognostic information on the type and extent of injury
Risk Factors for Complications During the Procedure
There are no known complications associated with nerve conduction studies.
What to Expect
Prior to Procedure
Your doctor will likely do the following:
- Physical exam
In the days leading up to your procedure:
- Avoid certain medications, if prescribed by your doctor.
- Shower the day of your test, and do not use any creams, moisturizers, or powders on your skin.
Anesthesia is not used for this procedure.
Description of the Procedure
Your skin will be cleaned, and 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.
Your doctor will analyze the data from the test, and a report should be available within a few days.
How Long Will It Take?
The procedure takes about 30-90 minutes.
Will It Hurt?
You will feel mild discomfort from the shocks, but it should not be painful.
There are no known risks associated with nerve conduction studies. If you have a pacemaker, let your doctor know prior to the study. In most cases, you can still have the test even if you have a pacemaker.
Average Hospital Stay
You will be able to go home after your procedure.
Special care is usually not required after this test.
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 May 2008 by J. Thomas Megerian, MD, PhD, FAAP
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.
Copyright © 2011 EBSCO Publishing All rights reserved.