An electromyogram, or EMG, is a test that measures the electrical activity of the muscles both at rest and during contraction, explains WebMD. The nerve conduction studies often done during the test measures how fast and well the nerves send signals.
The purpose of the electromyogram is to find conditions that may affect the nerves and muscles, according to WebMD. Some of these conditions are myasthenia gravis, herniated discs and amyotrophic lateral sclerosis. An electromyogram may also be done to find out why a muscle is twitching, weak or plagued with paralysis. This test cannot, however, test for any diseases of the spinal cord or brain.
Nerve conduction studies are sometimes done with an electromyogram in order to find nerve damage in the body, claims WebMD. This includes gathering information from nerves that lead away from the spinal cord, the brain and all of the nerves that branch out from them. This test is most often conducted to diagnose nerve issues, such as Guillain-Barré syndrome or carpal tunnel. Following the test, patients report soreness or tingling muscles for a couple of days. Pain can be treated at home by placing ice packs at the site of the test for 10 to 20 minutes at a time or by taking over-the-counter pain medication.