Electromyography testing is a common procedure to help find the proper diagnosis and treatment for muscular and nervous system issues. Every time a muscle contracts or relaxes, it requires electrical signals from the motor neurons that control it. When there is a problem with the muscles or nerves, measuring this electrical impulse can be a diagnostic tool.

When would a doctor use an EMG?

A doctor will use this test to investigate symptoms such as:

  • Unexplained muscle weakness
  • Tingling
  • Cramping
  • Involuntary movements
  • Numbness
  • Chronic pain

Physicians run this test to check for certain conditions. An EMG is a procedure used when trying to diagnose carpal tunnel syndrome. It can also help diagnose muscular disorders such as muscular dystrophy and nerve disorders like radiculopathy.


What happens during an EMG?

There are two steps to electromyography testing. In the first step, a doctor uses surface electrodes to measure how well a patient’s motor neurons are functioning. The electrodes measure the speed and strength of electrical signals. Because the electrodes emit a small charge during the test, the patient may experience involuntary twitching or tingling.
The second part of the test is the needle EMG. This test assesses electrical activity when a muscle is contracted or relaxed. A relaxed muscle should not have much activity. The doctor inserts an electrode needle through the skin and into the muscle tissue. Then, the patient contracts or relaxes the muscle in question. Depending on the location on the body, the patient may need to change positions during the test.

Is there any preparation for an EMG?

There is not much preparation required for this test. To get the best reading from the surface electrodes, the patient will want to avoid applying lotion or creams before the procedure. Patients on blood-thinning medications may need to stop to prevent excess bleeding or bruising during the needle EMG.

Are there any risks associated with an EMG?

An EMG is a safe and minimally invasive procedure. Patients may experience slight discomfort when the electrical charge travels between surface electrodes. Inserting a needle electrode will cause some pain and discomfort that quickly dissipates when the test is over. Because the procedure involves an electrical current, a patient should let the doctor or technician know if he or she has an electronic medical device like a pacemaker.