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

Electromyogram EMG
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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.


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.