What is an EMG/NCV
EMG stands for electromyography. NCV stands for nerve conduction velocity. Combined this is a sensitive test for nerve injuries. This test is commonly used to detect problems such as carpal tunnel syndrome, pinched nerves in your neck or back, generalized nerve injuries or muscle diseases. The test should only be performed by physicians trained as experts in electrodiagnostics.
Does it hurt?
This is often the first question we get asked before doing the test. Most patients find it mildly uncomfortable. The test involves small stimuli to the nerves similar to a strong static electricity charge. The test may also involve a small needle placed under the skin. The test is performed on young children without the need for pain medication. If you are taking a pain medication you may take this before the test but most people do not find this necessary. It is our policy to stop the test if a patient finds it to uncomfortable. Stopping for discomfort is extremely uncommon.
What kind of medical training do the doctors who do EMGs have?
Doctors who do EMGs go to 4 years of medical school then have 4 more years of training in a residency program. Most work as physical medicine and rehabilitation doctors or neurologist. 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. Dr. Todd Jorgensen, Dr. Jeffrey Hedden and Dr. Shawn Jorgensen have been certified as experts in electrodiagnostics by the American Academy of Electrodiagnostic Medicine. This certification required passing additional testing after residency training. Be sure that your EMG test is being performed by a physician who specializes in testing nerves.
Why am I being sent for EMG testing?
You are being sent for electromyography (EMG) testing 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. The EMG doctor will examine you to decide which tests to do based on your symptoms.
Nerve Conduction Studies
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.
Needle EMG (Electromyography)
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.
How long will these tests take?
The tests usually take 20 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.
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. In cold weather wear warm clothing. This includes gloves if your hands are to be tested or warm socks and boots if your feet will be tested.
When will I know the test results?
We will be happy to discuss your test results with you on the day of the test. After the exam, check with the doctor who sent you to the test for the next step in your care. Your doctor will have the results in a couple of days after the test or immediately if needed.
Portions reprinted with permission from the AANEM website.