Understanding the Terms

Two different tests are performed when a patient has an “EMG." Both are performed with an “EMG machine."  When a doctor orders an “EMG," he or she is typically referring to both components (a) nerve conduction studies and (b) EMG or electromyogram. It is important to understand that the term EMG includes both tests. Although an EMG technically refers to “electromyogram," it is an abbreviation for electromyogram and nerve conduction study. The two tests are usually performed together on the same day in a neurologist or a physiatrist's office with the assistance of technicians.

1. Nerve conduction study (NCS or NCV): This test determines if the nerves conduct current normally. Since the speed of conduction is measured, it is also called nerve conduction velocity (NCV). This test can be performed by a technician who is properly trained and supervised by a neurologist or a physiatrist. Preferably the technician should be certified (CNCT link) and the doctor board certified in electromyography (ABEM link). There are well accepted guidelines for the proper performance of these important tests. (AANEM performance). This test is usually done with an EMG. The two tests are complimentary.

It is critically important that this test (like any medical test) be done accurately and according to guidelines. The results determine what surgery or treatment is needed.

2. EMG or electromyography: This second component is usually performed immediately after the nerve conduction study. It must be done by a well-trained neurologist or a physiatrist. This test cannot be “read” later. It has to be performed and interpreted as the physician progresses with the study. Which muscles he evaluates depends on the information that was obtained immediately preceding. The doctor must be onsite and perform this personally. Again, there are guidelines (AANEM). This part of the test determines if the muscles are working normally. Muscles that are not working normally can be a sign of nerve or muscle disease or dysfunction.

Common Conditions that May Require an EMG/NCS

1. Carpal tunnel syndrome

2. Ulnar neuropathy

3. Peripheral neuropathy

4. Pinched nerve in neck or back (cervical or lumbar radiculopathy) nerve injuries

5. Basically any patient who experiences unexplained weakness, pain, numbness or tingling may be a candidate for an EMG.

Contact Information

EMG Audit
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