Electrodiagnostic testing or EMG is a test that evaluates nerve and muscle function. The test has two parts and usually takes about 45-60 minutes. The first part is called the Nerve Conduction Study (NCS) and the second is Electromyography or EMG. The NCS involves giving small electrical stimulations to nerves in the arms and/or legs. It is used to evaluate pain, numbness and weakness in a limb. The EMG involves the use of a small needle that is inserted into selected muscles in order to determine if the muscle has lost its nerve supply and therefore there is nerve injury. There can be discomfort with the test, but this can be easily controlled by the doctor performing the exam. Some people experience muscle tenderness for a day or two after the test, and some have minimal bleeding from the EMG needle sites.
Conditions frequently tested by EMG
- Carpal Tunnel Syndrome
- Radiculopathy (pinched nerve)
- Peripheral Neuropathy
- Myopathy (Muscle disease)
- Amyotrophic Lateral Sclerosis (ALS)
Preparing for an EMG?
Few preparations are needed on the day you have an EMG. You do not need to fast, or eat any particular kinds of food before the test. You can drive yourself to and from the appointment, do you do not need to bring a friend or relative with you. You can count on resuming your regular activity after the test is complete. As for clothing, it is best to wear loose fitting clothing so the doctor can evaluate your arms and legs easily.
Please do not apply lotions to your skin on the day of the exam as it can interfere with the test.
Please inform the doctor prior to the start of the test if you have any one of the following:
- Have a pacemaker or any other electrical medical device
- Take blood-thinning medications- medications such as Coumadin and Plavix will need to be stopped prior to the test
- Have hemophilia, a blood-clotting disorder that causes prolonged bleeding