What is an EMG/NCV study?
Electromyography (EMG) and Nerve Conduction Velocity (NCV) studies are ordered to evaluate nerve and muscles disorders.  Nerve conduction studies evaluate the function of the nerve by stimulating nerves and seeing how the impulses conduct across segments of the nerves. Electromyography evaluates the function of the muscle and the connection of the nerves to muscles. These studies should be considered an extension of a history and physical exam.

How is this test performed?
The person conducting the test will put little sticky electrodes on your arm or leg, and stimulate various nerves. To you, the stimulations will feel like little shocks.  This is the nerve conduction portion of the exam. The EMG portion is done by placing a very thin specialized needle one at a time into different muscles. The needle is not hollow, and nothing is being injected into the muscle. The needle is used to record or listen to your muscle activity. The test typically takes less than an hour.

Why was this test ordered?
AAre you experiencing symptoms, such as pain, numbness, tingling, weakness, muscle cramping in the arms or legs? Your doctor may want to evaluate for an injury to a nerve that can occur with various conditions, such as:

• Radiculopathy in the cervical or lumbar spine - pressure on the nerves roots as they exit the spinal column. In the lumbar spine the symptoms of numbness and tingling radiating into a leg is often called sciatica.
• Brachial and lumbosacral plexopathies.
• Peripheral neuropathies.
  
• Entrapment neuropathies:
  - Carpal tunnel syndrome - pressure on the median nerve as it crosses the wrist.
  - Cubital tunnel syndrome - pressure on the ulnar nerve as it courses around the elbow.

Is there any preparation the day of testing?
On the day of this test, please do not put any lotion or creams on the areas being tested. Typically the test is performed on both sides of the body for comparison. There are no restrictions of activity before or after the test. There are no lasting effects after testing. Occasionally you may notice some bruising in the muscles tested. Please notify your doctor if you are taking any blood thinning medications.

How accurate are these tests?
The accuracy of an electrodiagnostic test is dependent on the skill of the person conducting the test and the precision of the equipment used.  The experience and training of a board certified physician provides a level of quality that is often lost with diagnostic services that rely solely on interpretations by a technician or computer program. Along with a history and physical exam, this type of testing can accurately evaluate for injuries to the nerves and muscles.  Findings by this type of test may not be apparent for several weeks after an injury, so it is important for your ordering doctor to know the time frame of injury.  In addition, the results of this test do not reflect the existence of pain or quantify pain.

Dr. Kim, completed her medical residency at The Rehabilitation Institute of Chicago, which has been named the #1 rehabilitation hospital for 20 consecutive years. She is board certified by both The American Board of Physical Medicine and Rehabilitation (1998), and The American Board of Electrodiagnostic Medicine (2000).