An EMG, or electromyogram (e LECK tro MY oh gram), is a test that is done to show the electrical activity of the muscles. Electrical activity is normal and necessary for muscle movement. This test shows any change in that electrical activity.
The NCV, or nerve conduction velocity exam (NERV kon duc shun vel AH sit ee), tests the health of the nerves outside the brain and spinal cord.
Why the test is done
Your child’s doctor may order an EMG and NCV if the child has signs or symptoms that may indicate a nerve or muscle disorder.
Such symptoms may include:
- Muscle weakness
- Muscle pain or cramping
- Certain types of limb pain
Before the test
The neurologist conducting the EMG will need to know if your child has certain medical conditions. Tell the neurologist and other EMG lab personnel if your child:
- has a pacemaker, any other electrical medical device, or a central catheter
- takes blood-thinning medicines
- has hemophilia, a blood-clotting disorder that causes prolonged bleeding.
Parents may stay with their child during the test if they can help the child relax. In some cases,
it may be better for parents to wait in the waiting room. It is best if other children do not come with you. Please turn off all cell phones before going into the EMG lab.
Risks of the test
EMG is a low-risk procedure, and complications are rare. There is a small risk of bleeding, infection and nerve injury, where a needle electrode is inserted.
When muscles along the chest wall are examined with a needle electrode, there’s a small risk
that it could cause air to leak into the area between the lungs and chest wall, causing a lung to collapse (pneumothorax).
After the test is over, your child may experience some temporary, minor bruising where the needle electrode was inserted into the muscle. This bruising should fade within several days.
If it persists, contact your child’s primary care doctor.
NCV tests are non-invasive and there is no risk of side effects unless your child has an implanted medical device. Nothing is put into the skin, so there is no chance of infection. The voltage of electrical pulses is not high enough to cause an injury. If your child has a pacemaker, cardiac defibrillator, or other implanted medical device please notify the Neurology Department at (614) 722-4625.
How to prepare for the test
If your child is old enough, explain to him or her how the test is done (see page 4).
Beginning 6 hours before the test, do not give your child any of these drinks:
- No coffee
- No tea
- No soda
- No chocolate
These are stimulants and can keep your child from relaxing.
- Except for chocolate, your child may eat as he usually does before the test.
- Give your child his or her usual prescription medicines. Give medicine with a small sip
of plain water.
- If your child uses a medication patch, remove the patch before the test, put the sticky sides together, and flush it down a toilet. After the test replace your child’s patch with a new one.
- Be sure to tell the doctor if your child has any allergies. Bring a list of all the medicines your child is taking.
Try to keep your child awake before the test so that he or she will be sleepy. If the child is an infant, please bring formula, a clear liquid drink and a pacifier if your child uses one. Children may bring favorite blankets or toys. Older children may bring MP3 or CD players with headsets.
Have your child wear or bring loose-fitting shorts and a short-sleeved top. Children are more relaxed in their own clothes. Your child’s skin should be clean and free of lotions
How the test is done
- Your child will lie on a table. Small stickers, called electrodes, are placed on your child's legs and arms. Wires to the EMG machine (Picture 1) connect these electrodes.
- There are 2 parts to the test: the nerve conduction test and the muscle or EMG test. The doctor will do nerve conduction tests first. Most children do not mind
the tingling feeling of the small electric stimulation during these tests.
- To check the electrical activity in the muscle, the doctor inserts a very thin, coated wire into the muscle. The wire acts like an antenna. It allows the doctor to see and to hear the electrical activity. You and your child will also see and hear the response.
- Some children say this test hurts and others say they do not feel the wire at all. Any discomfort should only last a few minutes.
- The length of time the test takes is different for each child. Usually the test takes between 30 and 90 minutes to complete.
After the test
Your child may return to normal activity.
The test results will be sent to the doctor who sent your child for the test. The doctor who ordered the test will explain the results to you. If you want the test results sent to your family doctor, please be sure we have his or her name and address before you leave.
If you have any questions or your child cannot keep the appointment, please call the Nationwide Children's Hospital Neurology Department at (614) 722-4625.
12/16 Copyright 2016 Nationwide Children’s Hospital