Nerve Conduction Study – (NCS/NCV)

For a nerve conduction study:

• You will sit or lie down on a table or bed.
• Your provider will attach one or more electrodes to a certain nerve or nerves using tape or a paste. The electrodes, called stimulating electrodes, deliver a mild electrical pulse.
• Your provider will attach different types of electrodes to the muscle or muscles controlled by those nerves. These electrodes will record the responses to the electrical stimulation from the nerve.
• Your provider will send a small pulse of electricity through the stimulating electrodes to stimulate the nerve to send a signal to the muscle.
• This may cause a mild tingling feeling.
• Your provider will record the time it takes for your muscle to respond to the nerve signal.
• The speed of the response is called the conduction velocity.

If you are having both tests, the nerve conduction study will be done first.

Will I need to do anything to prepare for these tests?

Tell your health care provider if you have a pacemaker or cardiac defibrillator. Special steps will need to be taken before the test if you have one of these devices.

Wear loose, comfortable clothing that allows easy access to the test area or can be easily removed if you need to change into a clinic gown.

Make sure your skin is clean. Don’t use lotions, creams, or perfumes for a day or two before the test.

Are there any risks to the tests?

You may feel a little pain or cramping during an EMG test. You may have a tingly feeling, like a mild electric shock, during a nerve conduction study.

What do the results mean?

If your results were not normal, it can indicate a variety of different conditions. Depending on which muscles or nerves are affected, it may mean one of the following:

• Carpal tunnel syndrome, a condition that affects nerves in the hand and arm. It’s usually not serious, but can be painful.
• Herniated disc, a condition that happens when a part of your spine, called a disc, is damaged. This puts pressure on the spine, causing pain and numbness
• Guillain-Barre syndrome, an autoimmune disorder that affects the nerves. It can lead to numbness, tingling, and paralysis. Most people recover from the disorder after treatment
• Myasthenia gravis, a rare disorder that causes muscle fatigue and weakness.
• Muscular dystrophy, an inherited disease that seriously affects muscle structure and function.
• Charcot-Marie-Tooth disease, an inherited disorder that causes nerve damage, mostly in the arms and legs.
• Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease. This is a progressive, ultimately fatal, disorder that attacks nerve cells in your brain and spinal cord. It affects all the muscles you use to move, speak, eat, and breathe.

If you have questions about your results, talk to your health care provider.