Electromyogram (EMG) and Nerve Conduction Study (NCS)


What to Expect During Your EMG Test

Electrodiagnostic medicine studies diseases of the nerves and muscles. The EMG test your doctor has recommended studies if your muscles and nerves are working right. You can have problems with your muscles and nerves in only one part of your body or throughout your body. The EMG doctor examines you to decide what tests to do. The results of the tests will help your doctor decide what is wrong and how it can be treated.

Who does the testing?

The American Association of Electrodiagnostic Medicine’s policy is that an appropriately trained doctor should do all needle EMG (electromyography) testing. A trained assistant, a technologist, under a doctor’s supervision can do nerve conduction studies (NCSs).

What medical training do doctors who do EMGs have?

Doctors who do EMGs go to 4 years of medical school; and then have 3 or 4 more years training in a residency program. Most work as neurologists or physical medicine and rehabilitation doctors. Medical training helps the doctor decide which tests to perform based on your problems. It teaches doctors the things that can go wrong with the human body and how to tell the difference between these things.

Why am I being sent to the EMG Lab for tests?

You are being sent to the EMG lab because you have numbness, tingling, pain, weakness, and/or muscle cramping. Some of the tests that the EMG doctor may use are nerve conduction studies (NCSs) and/or needle EMG.


NCSs show how the body’s electrical signals are traveling to a nerve. This is done by applying small electrical stimuli to the nerve and recording how the nerve works. These stimuli cause a quick, mild tingling feeling. The doctor may test several nerves.

Needle EMG (Electromyography)

For this part of the exam, a small, thin needle is inserted into several muscles to see if there are any problems. A new needle is used for each patient, and it is thrown away after the test. There may be a small amount of pain when the needle is put in. The doctor examines only the muscles necessary to decide what is wrong. The doctor will look at and listen to the electrical signals that travel from the needle to the EMG machine. The doctor then reads these signals.

How long will these tests take?

The tests usually take 40 to 90 minutes. You can do any of your normal activities, like eating, driving, and exercising, before the tests. You also can do your normal activities after the tests. There are no lasting side effects from the tests.

How should I prepare for the tests?

Tell the EMG doctor if you are taking aspirin, blood thinners (like Coumadin®), have a pacemaker, or have hemophilia. Take a bath or shower to remove oil from your skin. Do not use body lotion on the day of the test. If you have Myasthenia Gravis, ask your EMG doctor if you should take any medications before the test.

When will I know the test results?

The EMG doctor will discuss your test results with you or send them to your regular doctor. After the exam, check with the doctor who referred you.

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