Electrodiagnostic medicine is the study of diseases of nerves and muscles. Your doctor has recommended an EMG test to see if your muscles and nerves are working right. You can have problems in only one part of your body or throughout your body. The results of the tests will help your doctor decide what is wrong and how it can be treated.
The American Association of Neuromuscular & Electrodiagnostic Medicine's policy is that an appropriately trained doctor should do all needle EMG testing.
Doctors who do EMGs go to 4 years of medical school then have 3 or 4 more years of 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 symptoms. It teaches doctors what can go wrong with the human body and how to tell the difference between these problems.
You are being sent to the electromyography (EMG) lab because you have numbness, tingling, pain, weakness, or muscle cramping. Some of the tests that the EMG doctor may use to diagnose your symptoms are nerve conduction studies (NCSs), needle EMG, and evoked potentials. The EMG doctor will examine you to decide which tests to do.
NCSs show how well the body's electrical signals are traveling to a nerve. This is done by applying small electrical shocks to the nerve and recording how the nerve works. These shocks cause a quick, mild, tingling feeling. The doctor may test several nerves.
For this part of the test, a small, thin needle is put in 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 tests 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 uses his medical knowledge to figure out what could be causing your problem.
The tests usually take 60 to 90 minutes. You can do any of your normal activities, like eating, driving, and exercising, before the tests. There are no lasting side effects. You can also do your normal activities after 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.
The EMG doctor will discuss your test results with you or send them to your referring doctor. After the exam, check with the doctor who sent you to the lab for the next step in your care.
Used by permission, copyright © 2005 AAEM. www.aanem.org