WHAT ARE EMG AND NCS?
EMG (Electromyography) measures the electrical activity of muscles and NCS (Nerve Conduction Studies) measure the speed and intensity of electrical signals that travel along nerves. These important diagnostic tools can help detect the causes of problems such as muscle weakness, numbness, muscle cramping, paralysis, or pain. They can determine if the problem involves the nerves, muscles, spinal cord or brain.
HOW SHOULD I PREPARE FOR THE TESTS?
Tell your physicians about any medications you’re taking, especially aspirin or blood thinners. Also, be sure to tell the doctor if you bruise easily, have hemophilia or diabetes, have a pacemaker, or if you have a skin infection. Bathe or shower in order to remove oil on your skin. Do not use any body lotions, oils or creams the day of the test.
WHO PERFORMS THE EMG AND NCS?
At the Neurological Group, the neurologists perform these tests with the assistance of a technologist. The physicians are board certified neurologists and have completed additional training in neurodiagnostic testing. Our neurodiagnostic technician is also fully trained.
HOW LONG WILL THE TEST TAKE?
The tests usually take 20 to 40 minutes. You can resume normal activities following these tests; there are no lasting side effects.
HOW DO EMG AND NCS WORK?
Nerve and muscle cells produce small amounts of electricity. Nerves send electrical signals to muscles, telling them to contract or relax. Muscles produce electrical activity when they move. If a nerve or muscle is injured or damaged by a disease, the electrical activity changes and the EMG and NCS equipment detects the changes in electrical activity. The electrodes record the electrical activity of a nerve or muscle, a computer displays and analyzes the data, a monitor displays the electrical activity and speakers allow the electrical activity to be heard.
The NCS (nerve conduction study) Procedure:
Electrodes will be applied to your foot/leg or hand/arm. A specific nerve will be stimulated with a small amount of electricity. There is no danger to you, as you will be grounded. This means that you are electrically safe. When you start to feel the electricity, it feels like a static shock at first. It gets progressively stronger and eventually will feel a definite shock. When there is enough electricity going down the nerve, the muscles controlled by that nerve will begin to contract. For example, your thumb will begin to jump when a nerve is stimulated at the wrist, or your toes will begin to jump when a nerve is stimulated at the ankle. The further up the nerve we go with the stimulation, the more motion we will get in the hand or foot. We will test both movement and feeling nerves using different electrodes.
The EMG (Electromyography) Procedure:
When the nerve studies are completed, your doctor may need to study how your muscles are functioning. He will use a very fine needle electrode which will be placed into a muscle. You will then be asked to use this muscle so the electricity you generate can be evaluated. You do not get any electricity from us during this portion of the test. A minimum number of muscles will be studied to get the maximum amount of information about their function.
WHEN WILL I GET THE RESULTS OF THE TESTS?
If the doctor performing your test is the doctor who ordered the test, you will get the results right away, once it is completed. If the testing was ordered by another doctor, you may get a general idea of the results, but the detailed information will need to go to the ordering physician before you can find out what the next step may be. A written report will be sent to your doctor within two to three days following your testing appointment.