What is an electromyogram?
An electromyogram, or EMG, is a test that checks the response of
muscles to messages sent by the nerves. The test measures the
electrical activity of muscles in response to stimulation.
When is it used?
An electromyogram can help diagnose problems such as:
- nerve damage or injury caused by a compressed disk in the neck
or back
- nerve compression in the hand from carpal tunnel syndrome
- muscle or movement problems, such as involuntary muscle
twitching
- muscle weakness from nerve disorders or diseases such as
muscular dystrophy
- nerve problems caused by conditions such as diabetes,
pernicious anemia, and heavy metal poisoning.
How do I prepare for an electromyogram?
Tell your healthcare provider before the test if:
- You have any bleeding problems.
- You have a pacemaker.
- You have allergies.
- You are taking any medicines.
On the day of the test, take a shower to remove body oil and do
not use body lotion.
How is the test done?
First you may be given a sedative to relax you. Your healthcare
provider will insert several small needle electrodes through your
skin into the muscles being tested. The electrodes record the
electrical activity of the muscles. Muscles may be tested when
they are resting, when contracting gently, and when contracting
forcefully. The test takes about 30 to 60 minutes to perform,
depending on the number of muscles being tested.
What happens after the test?
The muscles may feel tender or bruised for a few days after the
test.
How will I get the test result?
Ask your healthcare provider when and how you will get the result
of your test.
This content is reviewed periodically and is subject to
change as new health information becomes available. The
information is intended to inform and educate and is not a
replacement for medical evaluation, advice, diagnosis or
treatment by a healthcare professional.
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