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 information about the structure and function of both muscle and nerve.

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

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.

After Test

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.

Results

Your doctor will analyze the data from the test. A report should be available within a few days.

Call Your Doctor

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

In case of emergency, CALL 911 .

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.ccns.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/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 Rimas Lukas, MD

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.