What is an EMG/Nerve Conduction Study?
An Electromyography [EMG] and Nerve Conduction Study [NCS] measures muscle and nerve function.
EMG measures muscle function by the placement of a fine needle under your skin into the muscle being tested. This is then repeated in other muscles. The needle allows the electrical activity in your muscles to be measured. No electrical currents are applied with the needle.
During NCS, mild electrical currents are applied to the skin on parts of your body. This is done to see how quickly impulses travel between nerves.
During each test, wavy lines (waveforms) appear on the computer screen. These lines show how well your nerves and muscles are working. These waveforms help to determine your test results.
Before Your Test
To prepare for your test:
- Shower or bathe, but do not use powder, oil, lotion or petroleum jelly.
- Your skin should be clean and free of excess oil.
- Wear loose clothes.
- Take your routine medications, unless you are advised not to.
- You may be asked to change into a hospital gown.
- The entire test will take about one hour to complete.
Let the doctor know if you:
- Have any bleeding problems.
- Have any immune system problems.
- Take blood thinners (anticoagulants) or other medications, including aspirin.
- Have had neck or back surgery.
During Your Test
You will be asked to either sit in a chair and rest your arms on the exam table or lie down on the table in different positions.
You may have one or both of the following:
Nerve Conduction Study [NCS]
Small sticky disks (electrodes) will be attached to your skin on the area of your body being tested. A doctor will apply mild electrical currents to your skin. Although your muscles will twitch, the test will not harm you. Currents may again be applied to the same area. The test may continue to other parts of your body.
Most of the electrodes will be removed for the EMG. The doctor will clean the area being tested with alcohol. A fine needle will be inserted into the muscles in this region. When the needle is inserted, you may feel as if your skin is being pinched. Try to relax and do as instructed.
After Your Test
Before you leave, all electrodes will be removed. You will be able get back to your normal routine immediately following the test. If you feel tired or has some discomfort, take it easy. If you were told to stop taking any medications for your test, ask when you can start taking them again. Your doctor will let you know when your test results are ready.