What is an EMG Test?

This outpatient diagnostic test is used to evaluate the health of muscles and the nerves, called motor neurons, which control the muscles. Electromyography (EMG) is a valuable diagnostic device for determining the cause of muscle weakness and for identifying neurologic disorders.

EMG measures muscle response or electrical activity in response to a nerve’s stimulation of the muscle. The test is used to help detect neuromuscular abnormalities. During the EMG test, one or more small needles (also called electrodes) are inserted through the skin into the muscle.

EMG may help diagnose nerve compression or other injuries such as carpal tunnel syndrome, nerve root injuries such as sciatica, and other problems of the muscles and nerves.

Why Are EMG Tests Performed?

Your doctor may order an EMG if you have signs or symptoms that may indicate a nerve or muscle disorder. Such symptoms may include:

  • Tingling
  • Numbness
  • Muscle weakness
  • Muscle pain or cramping
  • Certain types of limb pain

EMG results are often necessary to help diagnose or rule out a number of conditions such as muscle disorders, carpal tunnel syndrome, amyotrophic lateral sclerosis, polio, and even herniated discs in the spine.

What to expect

The test is performed by inserting a needle electrode through the skin into the muscle. The electrical activity of the muscles is detected by the electrode and displayed on an oscilloscope. The activity may also be heard through a speaker. After placement of the electrodes, you may be asked to contract the muscle. The presence, size and shape of the wave form produced on the oscilloscope provide information about the ability of the muscle to respond when the nerves are stimulated.

The EMG test will take approximately 30 minutes to one hour. Patients are asked to refrain from using body lotions or oils on the skin the day of the test. No other preparation is necessary.

There may be some discomfort with the insertion of the electrodes, and the area may feel tender or bruised for a few days following the test. The test will not incapacitate you, and nothing will be injected into the body. In addition, the test will not affect work status or ability to drive.

We will be glad to file an insurance claim on your behalf; however, we require payment of deductibles, co-pays and/or percentages not covered by your insurance at the time of service. We will file and accept assignment on Medicare. HMO/POS patients must bring a referral.