Health Topics for Tests and Exams

Respiratory Care

Cellular Immunology Diagnostic Lab

Electromyogram (EMG)

An EMG evaluates a variety of problems such as:

• nerve damage or injury caused by a compressed disk in the neck or back
• nerve compression from carpal tunnel syndrome
• muscle or motor problems, such as involuntary muscle twitching
• neuromuscular diseases and
• inflammation or degeneration of peripheral nerves caused by such conditions as diabetes, pernicious anemia, and heavy metal toxicity

Before having an EMG, the patient will be advised to:

• stop using body lotions for several days before testing
• stop smoking for 24 hours before the test and
• refrain from drinking caffeinated beverages for 2 to 3 hours before the test

Patients with any bleeding problems, a pacemaker, allergies, or are taking medications should alert their healthcare provider before the test.  Failing to do so may put the patient at risk after the test.  Patients, who are extremely anxious or apprehensive, may be given a sedative before the test.

The EMG test takes about 30 to 60 minutes to perform, depending on the number of muscles to be tested.  Several needle electrodes are inserted through the skin into the muscles being tested.  The electrodes record impulses or electrical activity generated by the muscle when it is at rest, contracting gently, and contracting vigorously.  The results are studied to determine the source or cause of the muscle problem.

After the test, the muscle may feel tender or bruised for a few days.

Disclaimer:  This content is reviewed periodically and is subject to change as new health information becomes available.  The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.