EMG Nerve Test

Has your doctor ordered an EMG for you for the work-up for carpal tunnel syndrome? Are you wondering what to expect for your EMG? How does it test your nerves?

Let me give you a quick run through on what to expect.

What To Expect in an EMG

Good. Because you have good reason to wonder what to expect. An EMG is by no means a fun test, but it is an important test. It can give valuable information in helping to reach the diagnosis for your symptoms.

What is an EMG?

EMG actually stands for electromyography. When you are sent for an EMG, usually what are actually being sent for is a nerve conduction study as well as electromyography.

In broad terms, the two of these tests are used in conjunction with one another to determine the health of your nerves. The test can be used to diagnosis if you have nerve issues from neck or back issues such as sciatica or injury to other nerves. One example of another nerve is the median nerve, which is the nerve damaged in carpal tunnel syndrome.

Nerve conduction study

In nerve conduction study portion of the test, you will have some electrodes placed on your skin. There will be a small electrical stimulator that will send tiny electrical impulses down your nerves. These small shocks will be picked up by the electrodes. By looking at this data, your physician can determine the integrity of your nerves.

The electrical impulses are indeed tiny, but that does not mean that they feel “tiny”. Because the shocks are purposely directed near your nerves, it can feel like a tingling sensation or the sensation you get when you hit your funny bone. It is not comfortable by any means, but most people tolerate it just fine.

Nerves are used in our body to relay information about sensation and motor function.

When your nerves are being tested in the nerve conduction study for their sensation, the electrical impulses will be relatively small (and as stated above, uncomfortable).

When nerves are being tested for their motor function, the electrical impulses will be slightly stronger and you will feel your muscles jump or twitch – this is completely normal. Your muscles need to contract for the motor function of your nerves to be tested.


In the electromyography portion of the test, you will have a small needle placed into different muscle groups. The needle is relatively small and has a small microphone at the end of it. The needle itself is put into different muscles (not near nerves) and it essentially records your muscle activity.

When you are being tested, expect the needle to go into your muscle and have it moved around in the muscle. The needle needs to irritate the muscle to give information about the health of your nerve. At a certain point, the electromyographer will ask you to tense up the muscle. Again, this will give other types of information about the nerves leading to those muscles to the tester.

Oftentimes, multiple muscles will be need to be tested. Oftentimes at least 5-6 muscles will be tested. However, this number can change depending on what the electromyographer is testing for and also dependent on what they see.

As might imagine, the having a needle stuck in you multiple times is not fun. Nonetheless, most people tolerate it very well because the needle is relatively small.

How to Prepare for an EMG

The main thing you can do to prepare for an EMG is to take a good shower the day of testing as the test will require the tester to be relatively close to you and dirt or debris may make the test a little harder. Do NOT put on any lotion the day of testing because again this can mess up the results or make testing difficult.

I highly recommend that you dress up warmly, but in layers. The test requires your skin to be warm to be accurate. If you get cold hands or feet, consider wearing warm socks or gloves to warm them up before you get to the testing room.

When you are actually being tested, you will need to have your arm relatively exposed. This may mean that you need to change into a gown or if you dress in layers and have short sleeves on underneath, you may not need a gown.

You may also want to leave any jewelry such as watches or bracelets at home. During testing, the electromyographer will need access to your entire forearm, so bracelets or watches may hinder testing.


I know I just painted a very uncomfortable picture for the EMG, but RELAX! It’s not as bad as it sounds and at the end of the day, people that are nervous tend to experience more discomfort. They psych themselves up for a very uncomfortable test and become very tense. It becomes a self-fulfilling prophecy.

Leading up to the test or after the test if you or your prescribing physician are concerned primarily for carpal tunnel syndrome then it might do you well to wear a brace. Even without a confirmed diagnosis, wearing a brace will not hurt and can only help.

A Diagnosis Cannot Always Be Confirmed

Lastly, also realize that the test itself gives information about whether your nerves are damaged or not. Do not be disappointed if the test does not give any specific confirmatory diagnosis. Instead, you should be happy because this means that you do not have evidence of nerve damage.

Simply because the test does not see evidence of damaged nerves, does not mean that you are not having nerve-related pain. It just means that either your problem isn’t severe enough to have damaged your nerves (a good thing) or you have another problem that is causing your pain. Any other problem that is not nerve related (muscle-related, bone-related, chronic pain-related) will not be picked up on this test because it is not related to the nerve itself.