EMG (electromyography) is a test used to measure the electrical activity of a patient’s muscles. NCS (nerve conduction study), on the other hand, measures the intensity and the speed of the electrical signals that travel along the nerves, in addition to the reaction time for a response to these signals. Patients who require an EMG/NCS generally need a diagnosis relating to some sort of neuromuscular disorder. They help find the cause of a variety of conditions relating to muscles, such as paralysis, pain, spasms, numbnes and tingling, and weakness. Results can also help to pinpoint the location of the problem, whether it is in the muscles themselves or is originating from the spinal cord or nerves.
EMG/NCS is performed by Dr. Bernstein. He both conducts the test and interprets the results once they have been obtained. In the case of an EMG, a tiny needle will be inserted into a muscle in order to stimulate and measure electrical activity. A NCS will require two electrodes to be placed on the skin, and measurements will be taken as an electrical current travels the nerve between them.
Nerve Conduction Studies
NCSs show how well the body’s electrical signals are traveling to a nerve. This is done by applying small electrical shocks to the nerve and recording how the nerve works. These shocks cause a quick, mild, tingling feeling. The doctor may test several nerves.
Needle EMG (Electromyography)
For this part of the test, a small, thin needle is put in several muscles to see if there are any problems. A new needle is used for each patient and it is thrown away after the test. There may be a small amount of pain when the needle is put in. The doctor tests only the muscles necessary to decide what is wrong. The doctor will look at and listen to the electrical signals that travel from the needle to the EMG machine. The doctor then uses his medical knowledge to figure out what could be causing your problem.
How long will these tests take?
The tests usually take 20 to 90 minutes. You can do any of your normal activities, like eating, driving, and exercising, before the tests. There are no lasting side effects. You can also do your normal activities after the tests.
How should I prepare for the tests?
Tell the EMG doctor if you are taking aspirin, blood thinners (like Coumadin®), have a pacemaker, or have hemophilia. Take a bath or shower to remove oil from your skin. Do not use body lotion on the day of the test. In cold weather wear warm clothing. This includes gloves if your hands are to be tested or warm socks and boots if your feet will be tested.