Very short (less than a 1000th or 1/1000 of a second), safe bursts of electricity that may feel similar to a rubber band snapping against the surface of one’s skin are applied to stimulate each nerve to be studied. Most people describe the testing as more surprising than painful, and there are no long-term side effects. The electrical message needs to travel from the surface of your skin down to your nerve, so your skin will be scrubbed with alcohol to ensure that salts and oils are removed. Common sites that are stimulated include: the wrists, around the elbow, the ankle and around the knee. The series of pulses increases in intensity from something barely perceptible to something that may feel like an uncomfortable, startling, tingling sensation that is similar to an everyday static electricity shock. It is normal for one’s hand or foot to twitch in response to the impulse, and the time it takes for a muscle to respond is recorded. The technician is attempting to capture your nerve’s best ability to conduct the electrical message on the EMG machine.
The data that you and the technician collect together will be shared with your doctor who will interpret the results and immediately evaluate whether the second part of the test, the actual electromyography, is indicated. When it is, your doctor will insert a tiny disposable needle into selected muscles to examine the electrical activity in your muscle fibers. You will hear your own muscles “chatter” and be able to see the electricity in your muscles. The needle feels more like a small pinch since nothing will be injected. Your doctor has been specially trained to interpret what the “muscle language” signifies. He or she may ask you to tighten specific muscles. Essentially, it is a means to directly hear your muscles communicate their side of the story as it relates to your symptoms.