Electromyography, or EMG, involves testing the electrical activity of muscles. Often, EMG testing is performed with another test that measures the conducting function of nerves. This is called a nerve conduction study. Because both tests are often performed at the same office visit and by the same personnel, the risks and procedures generally apply to both tests.
Muscular movement involves the action of muscles and nerves and needs an electrical current. In some medical conditions the electrical activity of the muscles or nerves is not normal. Finding and describing these electrical properties in the muscle or nerve may help a doctor diagnose the condition.
EMG may aid with the diagnosis of nerve compression or injury (such as carpal tunnel syndrome), nerve root injury (such as sciatica), and with other problems of the muscles or nerves. Less common medical conditions include amyotrophic lateral sclerosis, myasthenia gravis, and muscular dystrophy.
An EMG records and analyzes the electrical activity in your muscles. It is used to learn more about the functioning of nerves in the arms and legs. When a normal muscle is at rest, it is electrically silent.
During an EMG, small, thin needles are placed in the muscle to record the electrical activity. When the needles are inserted, you may feel some pain and discomfort. The doctor will ask you to relax the muscle and to tense it slightly. The doctor will listen and watch a TV-like screen that broadcasts the electrical signals. You will also be able to hear the signal sounds as you move the muscle.
When the needles are removed, you may experience some soreness and bruising, but this will disappear in a few days. There are no long-term side effects.
If you are taking blood-thinning medications, have an illness, or are at risk for infection, tell the doctor who is conducting the test. On the day of the test, do not put any lotions or creams on the area to be tested and do not wear any jewelry. Usually, you can get the results immediately after the test.
