Your Doctor Ordered an Electromyography “EMG”; Now What?
If you have been experiencing unexplained muscle weakness, tingling, or numbness; your doctor may order an EMG. Read below to learn about the diagnostic procedure and what to expect:
What is an EMG?
Electrodiagnostic testing is utilized to help your physician determine if there is evidence of nerve or muscle injury that may be contributing to your symptoms. Standard electrodiagnostic testing involves two separate tests: nerve conduction studies (NCS) and electromyography (EMG).
Why is an EMG Performed?
Electrodiagnostic testing can aid in achieving a correct diagnosis to allow for implementation of appropriate treatments. Electrodiagnostic imaging can provide essential information regarding an underlying nerve disorder, such as entrapment neuropathies, carpal tunnel syndrome, peroneal neuropathies, polyneuropathies, brachial, and lumbar plexopathies. Neuromuscular disorders such as myasthenia gravis, Lambert Eaton syndrome, and botulism, as well as certain myopathies, can also be diagnosed using these studies. Radiculopathy is one of the most common reasons for having an EMG ordered. Radiculopathy can be caused by nerve root compression in the cervical, thoracic, or lumbar spine, but most commonly occurs in the cervical spine. Radiculopathy is a condition in which the nerve root is irritated and may present as weakness, pain, or numbness. The EMG test helps to clarify the cause of your symptoms by confirming and localizing the presence of nerve or muscle damage when exam findings or other diagnostic tests are not clear. The EMG often helps your physician to determine the exact location of nerve damage, the severity of damage and provides information on when the injury may have occurred. Information gathered by these studies is often useful in determining appropriate diagnoses and treatment options.
How is an EMG Performed?
In most cases, the EMG is performed after the NCS, as the information gathered during the NCS aids in the appropriate selection of muscles to be tested in the needle portion of the examination. The NCS measures the responses obtained by activating certain nerves in the upper and lower limbs. The choice of nerves to stimulate is contingent upon the presenting signs and symptoms. To perform the NCS, the electromyographer will use a stimulating device to deliver an electrical impulse along the nerve being tested. The delivered shock will feel similar to being shocked by static electricity (some shocks may feel stronger). The signal transmitted by your nerves are then recorded and displayed on the computer screen for analysis. After the NCS is performed, the electromyographer will perform a needle analysis of individual muscles in your arm, leg and/or along the spine. The needle is about the same size as an acupuncture needle. You will see and hear this electrical activity on the screen as your electromyographer will analyzes the activity. Combining the information from both tests, allows your physician a great deal of insight regarding the health of your peripheral nervous system from the spine all the way to the tips of your fingers and toes.
Are There Any Risks?
In general, some parts of the test (electrical shocks during NCS and needle insertion during the EMG) may be a little uncomfortable. There is no risk of serious injury to the nerve or muscles from having this test done. The vast majority of patients who do experience an increase in their pain after the test do very well with simple pain management strategies.
How Do I Prepare?
On the day of your test you may still wash your skin with soap and water, but do not rub any topical lotions on the arms or legs that are being tested. Also, if you are prone to having cold hands or feet, try to wear warm gloves or socks on the day of your test.
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