Electromyography (EMG) is a diagnostic procedure to assess the motor neurons that affect the muscles. The test may help determine the cause of symptoms such as weakness, pain, or cramping or monitor the progress of certain conditions, such as ALS (amyotrophic lateral sclerosis).
The test involves placing electrodes on the skin over the muscles being evaluated. Electrical activity is recorded and displayed on a monitor as the muscles contract. This activity can be used to assess muscle function and reveal abnormalities.