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EMG
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What is an EMG?
A test that measures the electrical activity of specific muscles and nerves
When is an EMG necessary?
 Neck, lower back, arm or leg pain  Unexplained muscle weakness  Clumsiness  Loss of sensation
Preparation:
Adults
 No special preparation necessary, although the use of skin moisturizing creams the day of
Understanding your EMG/NCS

Electrodiagnostic medicine studies diseases of the nerves and muscles. The EMG/NCS that has
been recommended is a test that studies if the patient’s muscles and nerves are working correctly.
Patient’s can have problems with their muscles and nerves in only one part of the body or
throughout the body.
A physician examines the patient to decide what test(s) to perform. The results of the tests will
help the physician decide what is wrong and how it can be treated. Many pain-related conditions
are caused by damage or malfunctioning of the nerves or nerve endings.
Bram Riegel, MD, is a board certified physiatrist who specializes in physical medicine and
rehabilitiation. Dr. Riegel is also board certified in performing EMG/NCS.
Why am I being sent for EMG/NCS?
Patient are sent for an EMG/NCS because they have numbness, tingling, pain, weakness and/or
muscle cramping. The physician may also be trying to rule out certain medical conditions. The
tests that are performed by Dr. Riegel include Nerve Conduction Studies (NCS) and Needle
Electromyography (EMG).
nerve conduction studies (NCS)
NCS’s show the body’s electrical signals that are traveling to a nerve. This is done by applying
small electrical shocks to the nerve and recording how the nerve responds. These shocks cause a
quick, mild tingling feeling. Several nerves may be tested.
needle EMG
For this portion of the exam, a small thin needle is inserted by the physician into several muscles
to see if there are any problems. Disposable needles are used for each patient. There may be a
small amount of pain where the needle is placed. The physician examines only the muscles
necessary to diagnose the issue. The physician will look and listen to the electrical signals that
travel from the needle to the EMG machine. The physician then interprets the signals and
documents them in a report.
how long do the tests take?
The tests usually take 60 minutes. The patient can take their pain medications or other
medications as usual. Normal activities like eating, driving, exercising can be performed before
and after the test. There are no lasting side effects.
how should I prepare for the test?
Please inform the scheduler and the physician if you are taking aspiring, blood thinners like
Coumadin, Warfarin or Plavix, have a Pacemaker, Defibrillator, or have hemophilia. Please take
a bath to remove oil on your skin. Do not use body lotion or oil on the day of the test.
when will I know the test results?
Dr. Riegel will send the results of the test to the referring physician to review with the patient.
After the exam, please follow up with you referring physician for the next step in your treatment
and review of the test results.
ELECTRODIAGNOSTIC
TESTING

What is Electrodiagnostic Testing?
The electrodiagnostic testing consultation is a direct extension of the neurologic portion of the
physical examination. The examination can be helpful in evaluating the causes of numbness,
tingling, pain, weakness, fatigue, and muscle cramping. Several types of tests are used to study
nerve and muscle function. These include nerve conduction studies (NCS), needle
electromyography (EMG), and evoked potentials.
An electrodiagnostic testing consultant undergoes special training in electrodiagnostic testing
procedures. The knowledge and expertise gained from such specialized medical training
maximizes the ability of the consultant to consider appropriate differential diagnoses in planning
and performing the electrodiagnostic examination. The expertise enables the consultant to assist
referring physicians in establishing diagnoses, determining prognoses, and assisting in proper
management.
The examination usually takes 20 to 60 minutes. There are no restrictions on activity before or
after the testing and there are no lasting aftereffects.
NCS and evoked potentials should be performed by a physician or a trained technologist under
the direct supervision of a physician. The needle EMG examination should be performed by a
physician with special training in this area.
Nerve Conduction Studies

NCS test how well signals travel along a nerve and can help find the cause of abnormal nerve
function. Signals are made to travel along the nerve by applying small electric pulses to the
nerve at one site and recording the response at a different place along the nerve. The small
electric pulses cause a short, mild tingling feeling. The nerve’s response is picked up by a
recording instrument and then is measured by the physician or technologist performing the test.
Several nerves may need to be tested depending on the type of problem.
Needle Electromyography Examination (EMG)
During the needle EMG portion of the examination, the physician inserts a small needle into a
muscle to record the electrical activity of the muscle. The electrical activity of the muscle is fed
into the recording instrument and the physician then analyzes it by looking at a signal on the
scope and listening to the sounds the activity makes through the speaker. This test can help
determine if there are abnormalities in the muscle or the nerve going to it.
There may be mild discomfort when the needle is inserted into the muscle. The needles are
discarded after use or sterilized before being used on another patient to prevent the transmission
of infections.
Evoked Potentials
Evoked potentials evaluate the function of nerve pathways that carry signal through the spinal
cord, vision pathways, and hearing pathways. Nerve signals are produced in these nerves by
applying small electric pulses to the nerves of the legs or arms, by pulses of light to the eyes, or
by clicks or sound to the ears. The nerve’s response is picked up from the skin over the surface
of the spinal cord or the head.
Special Precautions
You should inform the physician prior to the examination if you are on blood thinners or have
hemophilia. The physician should also be informed if you have a cardiac pacemaker or a spinal
column stimulator, or use a transcutaneous electrical nerve stimulator (TENS) unit. Avoid using
skin lotions the day of the test. If you have myasthenia gravis you should ask your physician
whether or not to take medications, such as Mestinon, before the examination.
Results
When the examination is completed, the electrodiagnostic medicine consultant will analyze the results and report them to the physician who referred you for the test. Your referring physician will use the test results to help decide on proper management.

Source: http://www.spine-sports.com/wp-content/uploads/2011/09/EMG.pdf