What to Expect During Your EMG Test
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. The results of the tests will help your doctor decide what is wrong
and how it can be treated.
Answers to Your Questions
What is an EMG?
EMG stands for ELECTROMYOGRAPHY. This term is routinely used to describe specialized tests which involve electrical testing of nerves and muscles. The two most commonly performed electrodiagnostic tests are: Nerve Conduction Studies (NCS), Electromyography (EMG).
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.
For this part of the test, a small, thin needle is put in several muscles to see if there are any problems.
It is used once for each patient and is thrown away after the test. There may be a small amount of pain during
this part of the examination. The doctor tests only the muscles necessary to decide what is wrong. During the EMG
test the doctor will be able to hear and see how your muscles and nerves are working by the electrical signals made
by your muscles. The doctor then uses his medical knowledge to figure out what could be causing your problem.
What is the purpose of the test?
These tests are helpful in finding the causes of numbness, tingling, weakness, cramping, pain, or other loss of function. The doctor who performs and analyzes these tests can tell if your nerves or muscles are not working properly.
Why is it necessary?
An electrodiagnostic study is the only test of nerve function and it can determine if nerve damage exists. The test results will assist your doctor in establishing a plan of treatment specific to your needs.
What kind of medical training do doctors who do EMGs have?
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.
Who does the testing?
The American Association of Neuromuscular & Electrodiagnostic Medicine's policy is that an appropriately trained
doctor should do all needle EMG testing. A trained assistant or technologist under a doctor's supervision can do
nerve conduction studies.
What should I do before the test?
On the day of the test, do not apply lotions or oils to the skin. This is to ensure the adhesiveness of the electrodes and proper responses.
Loose fitting clothing is recommended. Since a majority of the test is completed on your extremities, loose fitting clothes allow for better access.
How is the test administered?
Certain areas are cleansed of any dirt and oils on the surface of the skin to ensure the best results. Depending on which area is being tested, you may be asked to lay down or sit upright. Electrodes are placed over specific sites on the extremities and small electric impulses are applied (NCV). The impulse is a part of the test and is harmless. During the latter part of the test, a tiny pin electrode (EMG) is used to measure electrical activity in the muscle.
What are the Side Effects?
There are no lasting side effects from the tests, but the testing itself can sometimes be uncomfortable. The NCSs involve small electrical shocks to the nerve which may cause a quick tingling of pricking feeling along with an involuntary twitch of the arm or leg.
EMG studies use a thin needle inserted into several muscles. These needles are disposable and a new one is used for each patient. Like any needle, some discomfort may be felt.
How long will the tests take?
The tests typically take 30 to 60 minutes depending on the complexity of the case. It is imperative to arrive 20 minutes early for your appointment in order to ensure adequate test time.