EMG (Electromyography) Diagnostic Test for Neuromuscular Disorders

Neurosurgery at Mercy Baltimore

EMG, or electromyogram, is a diagnostic procedure used by our neurologists at The Neurology Center at Mercy to help diagnose symptoms that may suggest a nerve or muscle disorder.

What is an EMG (Electromyogram)?

An EMG or Electromyogram is a diagnostic procedure used to evaluate the electrical activity of muscles and the nerve cells that power them when relaxed and moving. Nerves cells or motor neurons send electrical signals that make the muscles relax and contract. The EMG test converts the electrical signals into graphs, sounds or numbers that are translated by an EMG trained specialist.

Using EMG, neurologists can determine if symptoms like tingling, numbness, muscle weakness, muscle pain or limb pain is associated with neuromuscular disorders like:

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How is an EMG performed?

An EMG can be performed by inserting a needle electrode into a muscle to record the electrical activity in the targeted muscle. The EMG is often performed along with a nerve conduction study.  

An EMG can be performed in several settings including a doctor’s office, clinic or in a hospital. Your muscles will need to relax during the EMG. You will sit in a reclining chair, or lie down on a bed or table.  The following will take place:

  • The area of the skin where the test will occur is cleaned.
  • A needle electrode is inserted into the muscle.

The electrode activity is recorded with the muscle at rest and contracted. If a reading is needed for different areas of the muscle, the electrode may be moved several times. An EMG procedure typically takes 30 to 60 minutes.

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How to prepare for your EMG:

The neurologist or the nerve specialist doctor will need to know your medical conditions such as:

  • Other electrical medical devices  or a pacemaker
  • Blood-thinning medications you may be taking
  • Blood clotting disorder like hemophilia you may have
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What to expect during and after an EMG Test:

Depending on your symptoms, the neurologists will place surface electrodes or needle electrodes on your skin where you are having symptoms. You may experience a spasm from the electrical current. If a needle electrode is used, there may be some discomfort until the needle is removed.

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How long is an EMG test?

The EEG test takes 30 to 60 minutes and is done as an outpatient procedure. If you received a sedative, it may take up to an hour to recover. You will need someone to take you home and you should not drive for the remainder of the day.