Electromyography and nerve conduction studies measure the electrical activity in muscles and nerves to determine the health of muscles and the nerve cells that control them. These tests are often performed together to give more complete information about nerve and muscle function. They may be used if you are having the following signs and symptoms:
- Muscle weakness
- Muscle pain or cramping
- Limb pain
Test results are used to help diagnose or rule out diseases and conditions that include carpal tunnel syndrome, muscular dystrophy, myasthenia gravis, peripheral neuropathy, myopathy and radiculopathy.
Electromyography (EMG) measures the electrical activity of muscles at rest and when they are contracted. For the test, a small, thin needle (similar to what is used for dry needling or acupuncture) is inserted into the muscles to record their electrical activity.
Nerve Conduction Study
A nerve conduction study (NCS) measures how well and how fast nerves are sending electrical signals. This test can help diagnose a nerve problem or locate an injury to the nervous system.
The NCS is performed by placing an electrode on the affected arm or leg and then applying a small amount of electrical current to measure the speed and strength of the electrical signal produced by the nerves. The patient may feel a slight “shock” sensation during the test.
How to prepare for the EMG/NCS
- Do not wear any lotion, creams or powders on the day of the test, as these products can interfere with results. Take a bath or shower to remove all oils, lotions and powders from your skin before the test.
- If you are taking blood thinners (such as Coumadin) or have a history of bleeding problems, please let us know.
- Please inform the clinic nurse and/or physicians if you have a pacemaker. We can still perform the test but will need to avoid testing in certain parts of the body.
What to expect
- The procedure usually takes 45 minutes to 1 hour. If more than two limbs are being tested, the procedure may take up to 90 minutes.
- You can return to normal activities after the procedure.
- You may feel some discomfort around the electrode insertion points during the test. If the limb being tested normally causes you pain, the level of pain may temporarily increase during the test. But you should start to feel better as the test proceeds.