Electromyogram / EMG and Nerve Conduction Test

The EMG / electromyogram is a test that evaluates the electrical activity in nerves and muscles. This test is helpful to determine if abnormalities exist in the way nerves transmit electrical impulses or abnormalities to the muscles themselves.

The EMG test consists of two parts:

  • Nerve conduction study (NCS), which evaluates the speed and amount of electrical activity along a nerve
  • EMG study, which looks at electrical activity in muscles at rest and also when they are voluntarily moved (if possible) to determine if the pattern of activity is normal

The patient will lie on an examination table, or very young children can sit on a parent’s lap. Electrodes are placed on the skin over the nerve to be studied. These electrodes act as microphones to pick up any electrical signal that goes by them.

An electrical stimulator is then placed on the skin near the electrodes and is used to create an electrical current strong enough to fully stimulate the nerve.

A computer is used to record responses as various nerves are tested. This allows the physician to measure and calculate how fast the nerve is sending the impulses to the muscle and measure the size of the impulse.

The muscles are assessed by inserting a pin electrode into the muscle with the computer then recording the muscle response both at rest and with movement. The sensation is similar to that of being stuck by a pin as the electrode is inserted into the muscle. (That is if sensory awareness is not a problem.)

It is important for the patient to stay as calm as possible to reduce discomfort and to achieve accurate readings.

  1. Please arrive before your appointed time to register; the exam actually runs on time as long as patients are not late. 
  2. Register in the Rheumatology and Rehabilitation Center, Location E, 2nd floor.
  3. You will be called to go back to the room.
  4. A child / young adult can continue with his / her usual diet (and medications) for this test. Washing arms and legs to remove any oils or lotions is helpful to obtain the best results when performing this procedure. Let the examiner know if the patient has a bleeding disorder or bleeds easily.
  5. The physician will discuss the child's history and explain how the test will be done before actually starting the EMG.

Does it hurt?

Parts of the test are uncomfortable but not severely painful. The anxiety before the test can be more of a factor than the test itself. A majority of the time spent with the patient is setting up the studies and running the computer; a very small amount of the time involves electrical stimulation or use of the pin electrode.

The electrical stimulation of the nerve conduction study could be compared to a static electricity shock from a doorknob after walking across carpet.

The pin insertion could be compared to being pinched by someone's fingernails. (And how do we know this? We have done it on ourselves first!)

Is sedation or anesthesia used?

Not in most cases. The test is fairly well tolerated and the patient needs to be awake to follow instructions, if possible, during the exam. However, a very mild dose of medication can be arranged if a patient or caregiver feels that it would be advisable based on past experience with procedures. You may bring a pacifier or bottle to help soothe an infant.

Please call the Pediatric Rehabilitation office at 513-636-7480 if this is a consideration or if you have questions.

Are there any side effects from a nerve conduction test or EMG?

There are no real side effects, but patients may experience some minor irritation at the pin insertion sites. Otherwise, there are no lasting effects from either the nerve conduction test or the EMG.

Is there an age limit on this test?

No, an EMG can be performed on any individual from infancy to old age. Infant and toddler exams can be more restricted because of inability to cooperate because of their young age.

Can the caregiver be in the room during the exam?

Yes, we have no restrictions on caregiver / parent presence in the room. It is up to these individuals as to whether they prefer to be in the room or not. It most cases, the parents / caregivers choose to stay in the room.

What should be done if the child becomes frightened during the test?

Reassure the child that everything will be explained to them before anything is actually done and that most children do very well during this test.

We make special effort to make the child as comfortable as possible. We have a large mat table where they can lie down and they can bring their favorite music on a portable player with headphones if this would be helpful (or anything else that can distract from the test). We also have a TV with DVD player available. A Child Life specialist may also interact with your child, using games and media during the test.

Will I get test results the same day?

The examining physician can give you an idea of any obvious abnormalities at the end of the test. However, more detailed interpretation will be done at a later time with a full report sent to the physician who referred the child.

The referring physician can better discuss the results as they will have knowledge of the EMG results along with the results from any other tests being done.

Who does the actual testing?

A physician (MD) who has received specialized training and has extensive experience will perform the test. At times there may be a physician in training present who will be observing or performing certain parts of the exam under direct supervision of the attending physician.

Last Updated 05/2015