EMG Clinic

EMG

Preparation

In most cases, no special preparation is necessary. Avoid using any creams or lotions on the day of the test. Risks are few, but you may experience some bleeding or infection at the electrode sites.

Procedure

For an EMG, we insert a needle electrode through your skin into the muscle. The electrical activity detected by this electrode displays on a laboratory instrument called an oscilloscope and may be heard through a speaker.

After placement of the electrodes, you may be asked to contract the muscle – for example, by bending your arm. The presence, size and shape of the waveform shown on the oscilloscope provide information about the muscle's ability to respond when the nerves are stimulated.

You may feel some pain or discomfort when the electrodes are inserted, but most people are able to complete the test without significant difficulty. Afterward, the muscle may feel tender or bruised for a few days.

NCV

Preparation

Tell your doctor if you have a cardiac defibrillator or pacemaker, as precautions may need to be taken. Otherwise, there are essentially no risks associated with NCV.

Procedure

We place surface electrode patches – similar to those used for an electrocardiogram – on your skin over the nerve at various locations. Each electrode gives off a very mild electrical impulse, which stimulates the nerve. The other electrodes record the nerve's resulting electrical activity. The distance between electrodes and the time it takes for electrical impulses to travel between them allow us to determine the speed of nerve signals.

The impulse may feel like an electric shock and may be uncomfortable. You will feel it to varying degrees, depending on how strong the stimulus is. You should feel no pain once the test is finished.