Electromyogram


The skin over the areas being tested is cleaned. A needle electrode is put into a muscle. The electrode is attached by wires to a recording machine.
When the electrodes are in place, the electrical activity in that muscle is recorded while the muscle is at rest. Then the technologist or doctor asks you to tighten (contract) the muscle slowly and steadily. This electrical activity is recorded.
The electrode may be moved a number of times. This is done to record the activity in different parts of the muscle or in different muscles.

The electrical activity in the muscle is shown as wavy and spiky lines on a video screen. It may also be heard on a speaker. You may hear popping sounds like a machine gun when you contract the muscle. The activity may also be recorded on video.
An EMG may take 30 to 60 minutes. When the test is done, the electrodes are removed. The places where a needle was put in the skin are cleaned.

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