Electromyogram (EMG)

An electromyogram (EMG) is a diagnostic test that measures the electrical activity of your muscles. It is done to detect certain nerve and muscle disorders that cause weakness, paralysis, and/or twitching of the muscles. An EMG usually lasts 30 to 60 minutes.

Preparing for an EMG

One week prior to your EMG, your doctor will give you specific instructions regarding your medications and any effects they might have against the test. About 3 hours before the test, you will not smoke or consume any caffeinated products. Patients are advised to wear comfortable, loose fitting clothing to their EMG. In some cases, a hospital gown is provided for the test.

During the EMG

In order to relax your muscles, the EMG is performed with you lying down or reclining. A special soap will be used to clean the areas of your skin being tested, and needle electrodes will be applied to those muscles.

Electrical activity will first be recorded of your muscles at rest. Your technician will then ask you to contract your muscles, and the resulting electrical activity will be recorded. The electrodes might be moved to different muscles or different portions of your muscles during the EMG. Your muscles’ electrical activity will be displayed on a special video screen; it might also recorded on video.

After the EMG

After your EMG, the electrodes are removed from your muscles, and your skin in the tested areas is cleaned. You may be prescribed medication for soreness in the tested areas. Soreness and tingling in the muscles is common for 1 to 2 hours following an EMG.

While full results of the EMG will not be available until 2 or 3 days later, you will be able to find out preliminary results immediately after the test.

Risks Associated with the EMG

Electromyogram (EMG) is an extremely safe procedure. There is a slight chance of swelling or bruising wherever the needles were placed, and chances of infection are minimal.