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What you 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 to 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.

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.

Contact your healthcare provider if:

  • You have a fever.
  • Your skin where the needles were inserted is red, swollen, or draining pus.
  • You have numbness or have trouble moving your arm or leg.
  • You have questions or concerns about your condition or care.


You may need the following:

  • Acetaminophen decreases pain and fever. It is available without a doctor's order. Ask how much to take and how often to take it. Follow directions. Acetaminophen can cause liver damage if not taken correctly.
  • Take your medicine as directed. Contact your healthcare provider if you think your medicine is not helping or if you have side effects. Tell him or her if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.

Care for your wound as directed:

Remove the bandage in 12 hours or as directed. Carefully wash around the wound with soap and water. Dry the area and put on new, clean bandages as directed. Change your bandages when they get wet or dirty.

Apply ice:

Apply ice on your wound for 15 to 20 minutes every hour or as directed. Use an ice pack, or put crushed ice in a plastic bag. Cover it with a towel. Ice helps prevent tissue damage and decreases swelling and pain.

Follow up with your doctor as directed:

Write down your questions so you remember to ask them during your visits.

© Copyright IBM Corporation 2021 Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or IBM Watson Health

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.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.