Electromyography (EMG) and Nerve Conduction Studies (NCS)

These tests can help your child’s healthcare provider find problems with the muscles and nerves. By testing different muscles and nerves electrically, it can help them find out where the problems are in your child’s body.

EMG and NCS are also called electrodiagnostic (ee-lek-tro-dye-ug-NOSS-tik) testing. Your child’s healthcare provider might order these tests if your child has any of these:

• Numbness or tingling feeling in parts of their body
• Weak, twitching or painful muscles
• Seeing double
• Droopy eyelids
• Other signs of muscle or nerve problems

• Your child can do their regular activities before and after the test.
• The testing usually takes 1 to 2 hours if your child gets both an NCS and EMG.
• During the testing, most children like to have their parents or caregivers in the room. There is not enough room for any other family members to be in the room during the test. Please arrange childcare for siblings in advance. Seattle Children’s does not offer childcare.
• The testing can be uncomfortable, but any pain or discomfort should go away within a couple of days.

On the day of the test (EMG or NCS), your child should:

• Take a bath or shower so their skin is clean.
• Avoid using any creams, oils or lotions. These make it difficult to do the test and can affect test results.
• Wear or bring a loose-fitting short sleeve shirt and shorts. Most of these tests are done on the arms and legs.

Tell the doctor performing the EMG the following before the test:

• About any bleeding disorders or skin infections your child has.
• About any medicines that your child is taking. This is especially important if your child takes blood thinners (anticoagulation) such as warfarin (Coumadin), or if your child takes pyridostigmine (Mestinon).
• If your child has a heart (cardiac) pacemaker, implantable defibrillator device or transcutaneous nerve stimulator (TENS).

• The doctor will attach electrodes to your child’s skin. These electrodes are like stickers with wires attached placed on the surface of the skin.
• Then, the doctor uses a hand-held device to send electric pulses to the nerve. Each pulse lasts only a split second—faster than an eye can blink. The electrodes will then measure how the pulse travels along the nerve.
• The doctor does this a few times on each nerve path to make sure the results are accurate. We may do the test on more than 1 nerve.
• The pulses might cause a short, mild tingling feeling, like a static charge. This can be uncomfortable, but it lasts less than a second each time the electric pulse is sent.

• The doctor will put a needle electrode through your child’s skin into each muscle that we need to test. Electrodes are thin wires that read the electrical activity within a muscle. The needle is a little smaller than the kind of needle used for shots. It feels about the same and will probably be uncomfortable for most children.
• We do not use numbing medicine (topical or local anesthetics), because they do not help with the muscle pain.
• The doctor will test the muscle when it’s relaxed and then ask your child to flex the muscle being tested. The electrode reads electrical activity in the muscle. Everyone will be able to see it on a screen and hear it through a speaker.
• Your child may bleed a little where the electrode was in the skin.
• The test area may feel sore or tender afterwards. This usually goes away very quickly but, your child may feel it for a couple days.

• Prevent the sites where the needle was inserted from getting dirty.
• It may help to put an ice pack on these areas during the first 4 to 6 hours after the test if they are sore.
• Over-the-counter pain medicine you normally give like acetaminophen (Tylenol) or ibuprofen (Advil or Motrin) can also help with soreness. Check with your healthcare provider first before giving any type of medicine to your child.

• We will finish the report within 48 hours and send the results to the provider who ordered the test.
• The healthcare provider who ordered the test is most familiar with your child’s problems, and they will talk to you about the results, what they mean, and what should happen next for your child’s care.
• The doctor who does the testing can talk to you about their initial findings on the day of the test. But they will not give you medical advice or a diagnosis (unless they ordered the test).