What is electromyography?
Electromyography (EMG) is a diagnostic procedure that evaluates the health condition of muscles and the nerve cells that control them. EMG results can help the doctor diagnose muscle disorders, nerve disorders, and disorders affecting the connection between nerves and muscles.
Why is electromyography performed?
Your doctor may perform an EMG if you’re experiencing symptoms that may indicate a muscle or nerve disorder. Some symptoms that may call for an EMG include:
- muscle weakness
- muscle pain or cramping
How do I prepare for electromyography?
Make sure to notify your doctor about any over-the-counter or prescription medications you may be taking. It’s also important to tell your doctor if you have a bleeding disorder, or if you have a pacemaker or implantable defibrillator. You may not be able to have an EMG if you have any of these medical conditions or devices. If you are pregnant let your doctor know too, as it may be relative contraindication.
If you’re able to have an EMG, you should do the following beforehand:
- Avoid smoking for at least three hours before the procedure.
- Bathe or take a shower to remove any oils from the skin. Don’t apply any lotions or creams after washing.
- Wear comfortable clothing that doesn’t obstruct the area that your doctor will be evaluating. You may be asked to change into a hospital gown right before the procedure.
What happens during an electromyography?
You will be asked to lie down on an examination table or to sit in a reclined chair. Your doctor may ask you to move into different positions during the procedure.
There are two components to an EMG test: the nerve conduction study and needle EMG. The nerve conduction study is the first part of the procedure. It involves placing small sensors called surface electrodes on the skin to assess the ability of the motor neurons to send electrical signals. The second part of the EMG procedure, known as needle EMG, also uses sensors to evaluate electrical signals. The sensors are called needle electrodes, and they’re directly inserted into muscle tissue to evaluate muscle activity when at rest and when contracted.
The nerve conduction study is performed first. During this portion of the procedure, your doctor will apply several electrodes to the surface of your skin, usually in the area where you’re experiencing symptoms. These electrodes will evaluate how well your motor neurons communicate with your muscles. Once the test is complete, the electrodes are removed from the skin.
After the nerve conduction study, your doctor will perform the needle EMG. Your doctor will first clean the affected area with an antiseptic. Then, they will use a needle to insert electrodes into your muscle tissue. You may feel slight discomfort or pain while the needle is being inserted.
The needle electrodes will evaluate the electrical activity of your muscles when contracted and when at rest. These electrodes will be removed after the test is over.
Your diagnosis will depend on other information in your medical history and your physical symptoms.
There’s no single path to recovery from a damaged or diseased nerve. Treatment varies according to your specific condition, for example, and which nerve is affected.