Diagnostic Procedures - Electromyogram (EMG)

The EMG is used as a diagnostic tool for infants with birth brain injuries. Depending on the type of brain injury, the test may occur when the baby is a few days old or several months old.

Our bodies have an incredibly complex system of nerves. These nerves, controlled by the brain, send electrical signals through the body to do things like contract muscles. A neurologist can interpret the results of an EMG to determine how well your child’s nerves and muscles are conducting electricity. The test is useful in diagnosing various types of neurological abnormalities that might be present at birth.

What is an EMG?

An EMG is a medical test that detects electrical activity of muscles in response to nerve stimulation. This invasive examination is used by neurologists to determine if your child has problems with neuromuscular irregularities. The examination consists of one or more electrodes inside small needles that are inserted through the skin into the muscle. An oscilloscope picks up the electrical activity and shows it on a monitor in the form of waves. You can also hear the waves through an audio amplifier.

The EMG detects electrical signals from the muscles during rest, mild contraction, and forceful contraction. As the doctor inserts the electrode needle, the oscilloscope will show a brief signal, but after that don’t expect to receive any signals when muscles are at rest.

What happens during the EMG?

The procedure is performed by a neurologist who specializes in brain and nerve disorders. The doctor will determine which muscle area to be examined. You may have to remove some of the baby’s clothes as needed. First, the doctor cleans the infant’s skin with antiseptic then inserts a thin needle into the muscle. Another electrode is placed elsewhere to act as a ground. Multiple needles may be inserted depending on the information needed. The electrical activity is then displayed on a monitor and played through an amplifier. The neurologist immediately reads and interprets the results from the monitor.

Does the Procedure Hurt?

It can. There is a feeling similar to getting shots when the needles are inserted. The infant may experience muscle soreness or discomfort over the following days. Parents may want to ask their doctor if giving infant pain medicine is appropriate to alleviate discomfort.