Tests and Treatments Electromyography (EMG) An Electromyography (EMG) provides evidence of nerve and muscle disease and often determines the cause of the problem. An EMG consists of three parts: A directed history and neurological exam Nerve condition studies (NCS) The actual EMG prcoedure What to Expect The history and neurologic exam help us learn whether the problem is neurologic or neuromuscular, determine which nerves or muscles are most affected, and focus the NCS and EMG. The whole process takes 10-15 minutes. NCS takes about 30-45 minutes. Surface electrodes are taped over several of the patient's key "zones" and muscles. The nerves that supply those zones or muscles are stimulated with a surface probe, and the resulting electrical responses are recorded. These stimuli feel like a small shock. EMG is performed last and takes about 5-15 minutes. A small needle electrode (smaller than the needle used to draw blood) is placed in one or more muscles in the arm, leg or back. Electrical activity of the muscle is fed through the electrode to the EMG machine. There might be some slight pain, but it lasts for only a few seconds. At the end, the results of each exam are considered together to reach a precise diagnosis. A detailed report is produced and sent to the referring physician within 48 hours. How to Prepare Patients aren't required to do anything in particular to prepare for an EMG test.