Elec­tromyo­g­ra­phy (EMG) –Test and Procedure

Dr. Daniel Gen­dron
MUHC /​CUSM, 1999

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1. About the Test
2. Before the Test: Prepa­ra­tion
3. Dur­ing the Test
4. After the Test
5. Out­pa­tient Check-​In
6. Addi­tional Resources & Information


What is an elec­tromyo­gram (EMG)?
An elec­tromyo­gram (EMG) is a test that mea­sures elec­tri­cal activ­ity of the nerves and mus­cles. This test is done to eval­u­ate how your nerves and mus­cles are functioning.

Who per­forms the test?
It is done by a tech­ni­cian and, usu­ally, a neurologist.

Why is it done?
An EMG is done to con­firm or eval­u­ate mus­cle dis­ease or nerve dis­ease. For exam­ple, if you have weak­ness in your arms, legs, hands, or face, an EMG may be done to find out the rea­son you have this symptom.

Are there any risks or side-​effects asso­ci­ated with this test?
There are no risks. In the days after the test, you may feel some minor dis­com­fort or sore­ness if you have had the part of the test that involves the exam­i­na­tion of a mus­cle with a nee­dle in it. If you expe­ri­ence any dis­com­fort or sore­ness, you will feel it close to the spot where a nee­dle (elec­trode) was inserted into the muscle.

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How do I pre­pare for this test?
No prepa­ra­tion is nec­es­sary. You may eat before the test. You may con­tinue to take med­ica­tions, as usual.

What hap­pens before the test?
There is usu­ally a brief phys­i­cal exam before the test.

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How long does it take?
The test can take 15 min­utes to 90 min­utes. It depends on the prob­lem that is being tested. For exam­ple, carpel tun­nel syn­drome takes around 15 min­utes to study.

How is it done?
It is done by dif­fer­ent tech­niques. Small elec­tri­cal stim­uli are admin­is­tered to dif­fer­ent nerves, and their response is analysed. To test mus­cle func­tion, a small dis­pos­able nee­dle (an elec­trode) is inserted in your mus­cles, and elec­tri­cal activ­ity is recorded. These data are analysed by the doc­tor doing the test.


What will I feel?
The elec­tri­cal stim­u­la­tion feels like tiny elec­tric shocks. Although it may cause min­i­mal dis­com­fort, it is easy to tol­er­ate. You may expe­ri­ence some pain (min­i­mal to mod­er­ate) when the nee­dle is inserted into each of the mus­cles to be tested.

Is any­thing injected into my body?
No. Noth­ing is injected into your body dur­ing this test.

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What hap­pens after the test?
You may return to your hos­pi­tal room or home, unless given other instructions.

When and how will I receive the results of my test?
The results of the test will be explained to you and you will be pro­vided with a hand­writ­ten pre­lim­i­nary report. A full report will be sent to your doctor.

The EMG lab­o­ra­tory is located on the third floor, in room 365. There is a wait­ing room directly across the hall. Our phone num­ber is 3981919.

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Out­pa­tient Check-​in
The EMG lab­o­ra­tory is located on the third floor, in room 365.
There is a wait­ing room directly across the hall.
Our phone num­ber is (514) 3981919

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Infor­ma­tion about InfoNEURO
Neuro-​Patient Resource Cen­tre
Mon­treal Neu­ro­log­i­cal Hosp­tial Room 354
Tel: (514) 3985358
E-​mail: infoneuro@​muhc.​mcgill.​ca
Web site: http://​infoneuro​.mcgill​.ca/

This infor­ma­tion is for edu­ca­tional pur­poses only, and is not intended to replace the advice of a pro­fes­sional health­care prac­ti­tioner, or to sub­sti­tute for med­ical care.

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Pre­pared for the Neuro-​Patient Resource Cen­tre by Dr. D. Gen­dron.
Reviewed by Dr. J. Stew­art, and by G. Fitzger­ald N. MSc(A) Chair of the Patient Teach­ing Com­mit­tee. Octo­ber 1999.
McGill Uni­ver­sity Health Cen­tre.

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