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Medically reviewed by Last updated on Jan 5, 2023.

What do I need to know about electromyography?

Electromyography (EMG) is a test that measures the electrical activity of your muscles. Your nerves send signals to your muscles to help them move. An EMG will tell your healthcare provider how well your muscles and nerves work together. A nerve conduction study (NCS) is usually done at the same time as an EMG. An NCS measures how fast electrical activity travels through your nerve to your muscle. Together, these tests can help diagnose conditions such as muscular dystrophy, myasthenia gravis, and nerve disorders.

How do I prepare for electromyography?

Your healthcare provider will talk to you about how to prepare for your test. Tell your healthcare provider if you have a pacemaker. Your healthcare provider will tell you what medicines to take or not take on the day of your test. You may need to stop taking blood thinners, NSAIDs, and aspirin 24 hours before the test. Do not have caffeine or smoke for 2 to 3 hours before the test. Do not apply lotions or creams to your skin on the day of the test. Wear loose-fitting clothing to the test. You may be given medicine to help you relax before the test.

What will happen during electromyography?

  • Your healthcare provider will attach sticky pads to your arm or leg. The provider will also insert 1 or more needles through your skin and into your muscle. You may feel discomfort or pain when the needle is inserted. The needle and sticky pads will be attached to wires and monitors. The monitors will record the electrical activity of your muscle.
  • A small electrical shock will be sent through the sticky pads to your muscle. This will make your arm or leg twitch. You may feel a sting during the shock. You may be asked to lift or bend your arm or leg. When the test is finished your healthcare provider will remove the needle and wires. The provider may hold pressure over your wound and cover it with a small bandage.

What will happen after electromyography?

You may have bruising or pain where the needle was inserted. This should get better in a few days.

What are the risks of electromyography?

Your nerves may be injured during the test. You may get an infection. You may develop soreness, bruises, or bleeding where the needles were put into your skin.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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Further information

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