What Is EMG?

Electrodiagnostic Testing to diagnose and monitor nerve and muscle conditions

What Is Electrodiagnostic Testing?

To determine whether your nerves and muscles are working properly, your doctor may recommend you have electro-diagnostic (EDx) testing. This will usually consist of nerve conduction studies (NCS) and a needle electromyography (EMG) testing. Most testing takes about 45 minutes to an hour depending on how many studies are performed or limbs are tested. Please do not wear any lotions, creams or oils on the areas to be tested 24 hours prior to your procedure.

NCS involve using a small electrical impulse, applied from an electrode over your skin, measured from point A to point B along the course of the tested nerve. Your doctor then measures the signal strength and time along the course of the nerve to help evaluate the proper functioning of the nerve or associated nerve roots.

EMG measures the electricity within a tested muscle. A small pin is inserted through the skin, into the muscle. The pin acts like a probe or microphone, helping the examiner measure the electric behavior of the muscle at rest and as it contracts. These tests measure how the nerves and muscles are working and can give your doctor complementary information to other diagnostic studies.

In summary, EDx testing gives your doctor electrophysiologic data, i.e. How are things working? As opposed to how they might look on an X-Ray or MRI scan. The testing can help asses for nerve or nerve root lesions as well as muscular problems such as nerve root problems, neuropathies, carpal tunnel syndrome, myopathies, and certain other nerve and muscle disorders.

FAQ's

In order to determine whether your nerves and/or muscles are working properly, your doctor may recommend you have electro-diagnostic (EDx) testing. This will usually consist of nerve conduction studies (NCS) and a needle electromyography (EMG) testing. 

NCS involve using a small electrical impulse, applied from an electrode over your skin, measured from point A to point B along the course of the tested nerve. Your doctor then measures the signal strength and time along the course of the nerve to help evaluate the proper functioning of the nerve or associated nerve roots.

EMG measures the electricity within a tested muscle. A small pin is inserted through the skin, into the muscle. The pin acts like a probe or microphone, helping the examiner measure the electric behavior of the muscle at rest and as it contracts. These tests measure how the nerves and muscles are working and can give your doctor complimentary information to other diagnostic studies.

Most testing takes about 45 minutes to an hour depending on how many studies are performed or limbs are tested. 

Please do not wear any lotions, creams or oils on the areas to be tested 24 hours prior to your procedure.

There may be a only mild discomfort with both types of tests. If you have had “e-stim” in physical therapy, nerve conduction tests will have a familiar sensation. If you have had acupuncture, EMG testing will feel similar.

It gives us physiologic data, i.e., how nerves and muscles are working, as opposed as to how they might look on an MRI scan. The data can be used to help establish and accurate diagnosis and help guide treatment. 

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