Posted October 2, 2022 by Anusha ‐ 2 min read

Electromyography (EMG) is a diagnostic test that measures how the muscles and nerves work. Providers insert thin needles through the skin and into the muscles. When you move your muscles, electrodes on the end of the needles measure activity in the muscles.

What is Electromyography (EMG)?

  • Electromyography (EMG) is a diagnostic test.

  • Your doctor may order this test to help evaluate the health and function of your nerves and muscles.

  • An EMG may be recommended if you have symptoms such as have muscle weakness or numbness and tingling.

What is the use of Electromyography?

Results from these tests help your healthcare provider diagnose a wide range of conditions, disorders, and injuries affecting the nerves and muscles.

How does Electromyography work?

  • The EMG study usually includes two parts: 1) Nerve Conduction Studies (NCS) and 2) Needle electrode examination (NEE).

  • During the first part of the test (NCS), small discs are placed on the skin to record nerve function.

  • Mild electrical stimulation is then applied over the skin to test the ability of the nerves to carry the electrical impulse to the recording discs.

  • You can think of your nerves as being similar to electrical cables.

  • A damaged cable will prevent electricity from running through it and powering the devices it is attached to (such as your TV).

  • In a similar way, damaged nerves will prevent electrical signals from running through and being recorded by the discs attached to your skin.

  • During the second part of the test (NEE), a tiny needle is placed into muscles to directly test the function and health of the muscles.
  • A mild pinprick sensation may be felt when the needle is placed into the muscle.
  • During this part of the testing, no electrical stimulation is delivered through the needle and nothing is injected through the needle tip.
  • You can think of the needle as being similar to a microphone.
  • It is only a recording device.
  • The needle is attached via a cable to a computer which allows your physician to both hear and see what your muscle is doing both at rest and with movement.

How to prepare for Electromyography?

Before you have an EMG, you should:

  • Bathe or shower. Wear comfortable, loose-fitting clothing.
  • Avoid putting cream, lotion or perfume on your skin.
  • Creams and lotions can affect the test’s accuracy.
  • Tell your provider if you’re taking blood thinner medication (anticoagulants) such as warfarin.
  • Blood thinners may increase your risk of bleeding after an EMG.
  • But don’t stop taking your medication without talking to your provider.

Risks of Electromyography

  • EMG is generally safe.

  • Complications are rare.

  • Some people (especially people who take blood thinner medications) may bleed after the test.

  • Rarely, infections can occur where the needles entered the skin.

lab-tests lab-investigations investigations electromyography

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