Electrodiagnostic Examinations

There are two main parts to every test, the NCS and needle EMG: 

1. NCS (nerve conduction study):  This part of the test is done first.  It  evaluates how your nerves are conducting signals to muscles (to make them move), or transmitting sensation (feeling) from your skin.  Electrode stickers are applied to your skin; a small, brief electric shock is delivered to specific nerves; and the responses are recorded as tracings on a screen.   The nerves tested and the number of nerves tested depends on your specific symptoms.

2. Needle EMG:  This part of the test evaluates specific muscles both when you relax the muscle and when you contract the muscle.  During the test, electrode stickers are applied to your skin, and the doctor will insert a small needle into the muscle and ask you either to relax the muscle or to contract the muscle.   The muscle response is viewed as a tracing on the screen.   The muscles tested and the total number of muscles tested depends on your specific symptoms.