Electromyography

Electromyography (EMG) and nerve conduction studies (NCS) are tests that measure muscle and nerve function. In most cases, both tests are performed. NCS is most often done first.

During NCS, mild electrical currents are applied to the skin on some part of the body. This is done to see how quickly impulses travel between nerves.

EMG assesses muscle function. To do this, a fine needle is placed under the skin into the muscle being tested. This is repeated on other muscles as needed. The needle allows the electrical activity in the muscle to be measured. No electrical currents are applied with the needle.

During each test, wavy lines (waveforms) appear on the screen. These lines show how well the nerves and muscles work.

This is a tool used to diagnose many chronic pain symptoms.