An electromyogram, also called EMG and electromyography, is a test that evaluates electrical activity within your nerves and muscles. Your doctor may recommend an EMG to help diagnose muscle weakness, muscular dystrophy, and other neuromuscular abnormalities. An EMG test involves inserting tiny needles into your muscles to record electrical activity.
An EMG is only one method used to diagnose neuromuscular abnormalities. You may have less invasive testing options depending on your condition. Discuss all your diagnostic options with your doctor to understand which options are best for you.
Other procedures that may be performed
Your doctor may perform other procedures in addition to and EMG to diagnose neuromuscular abnormalities including:
Evoked potentials to analyze the electrical functioning of the nervous system. This test checks the nerve pathways through the spinal cord or from the eyes and ears. Evoked potentials can help diagnose dizziness, numbness, tingling, and visual disorders.
Nerve conduction velocity to study how well electrical signals travel through a nerve
Your doctor may recommend an EMG to diagnose muscle and nerve diseases and conditions including:
Carpal tunnel syndrome, compression of the median nerve in the wrist
Charcot-Marie-Tooth disease, a neurological disorder causing damage and weakness to nerves in the arms and legs
Muscular dystrophy, an inherited disorder that causes a progressive loss of muscle tissue and muscle weakness
Myasthenia gravis, an autoimmune neuromuscular disorder that causes muscle weakness
Polymyositis, muscle inflammation that causes decreased muscle power
Sciatica, compression, injury or inflammation of the sciatic nerve which causes burning or shooting pain running from the buttocks down the back of the leg
A neurologist or pediatric neurologist performs an EMG. A neurologist specializes in diagnosing and treating diseases of the brain and nervous system. A pediatric neurologist specializes in caring for infants, children and adolescents with diseases and conditions of the brain and nervous system. A technologist may assist your neurologist during the procedure.
Your EMG will be performed in a hospital or outpatient setting. The procedure takes one to three hours and generally includes these steps:
You will dress in a patient gown and remove any items that may interfere with the an electromyogram.
You might take a mild sedative.
You will lie or sit down.
Your care team will clean the needle insertion points on your skin with an antiseptic cleanser, and then insert the needles containing electrodes into your skin. The number of needles depends on the types of muscles your doctor is studying. You may feel a pinch as each needle goes into your skin.
You will relax and contract certain muscles while a special machine records the electrical activity of the muscles.
You may hear sounds when you contract your muscles if your doctor is using an audio device during your electromyogram.
Your care team will remove the needles and may apply warm compresses and give you pain medication.
The neurologist will evaluate your EMG test results. The neurologist will send a report to your primary doctor who will discuss the results with you.
Will I feel pain?
Your comfort and relaxation is important to you and your care team. You may feel quick pinches during the needle placement. Tell your doctor or care team if any discomfort does not pass quickly or you are uncomfortable in any way. Pain may distort your test results, requiring a repeat test.
You may have mild soreness where the needles were inserted. Your doctor will prescribe pain medication as needed.
Complications of an EMG are not common, but any medical procedure involves risk and potential complications. Complications of an EMG are generally minor, temporary side effects. Complications of an EMG include:
Muscle soreness or tenderness
Some people who should not have an EMG include those who:
Take blood thinning medication, which increases the risk of bleeding into the muscle
Have a moderate to serious skin infection, which can spread to the muscle
Reducing your risk of complications
You can reduce the risk of some complications by following your treatment plan and:
Following activity, dietary and lifestyle restrictions and recommendations before your procedure and during recovery
Informing your doctor if you have any metal in your body, including screws, pins, plates, pacemakers, implants of any kind, intrauterine devices (IUDs), and bullet fragments
Notifying your doctor right away of any concerns, such as bleeding, fever, or increase in pain
Removing all jewelry and metal objects and leaving them outside the procedure room. This includes glasses, credits cards, hair accessories, and removable dental work.
Taking or stopping your medications exactly as directed
Telling all members of your care team about your medications, medical history, and allergies
You are an important member of your own healthcare team. The steps you take before an EMG can improve your comfort and help obtain the most accurate test results.
You can prepare for an EMG by:
Answering all questions about your medical history, allergies, and medications. This includes prescriptions, over-the-counter drugs, herbal treatments, and vitamins. It is a good idea to carry a current list of your medical conditions, medications, and allergies at all times.
Arranging for a ride home if sedation will be used
Following all instructions about eating and drinking before your EMG
Following activity, dietary and lifestyle restrictions before your EMG
Leaving jewelry, metal objects, credit cards, and other valuables at home
Not using lotions or oils on your skin before the test as directed by your doctor
Taking or stopping medications exactly as directed. Your doctor will give you specific instructions about taking your medications.
Questions to ask your doctor
Having an EMG can be stressful. It is common for patients to forget some of their questions during a brief doctor’s office visit. You may also think of other questions after your appointment. Contact your doctor with concerns and questions before an EMG and between appointments.
It is also a good idea to bring a list of questions to your appointments. Questions can include:
Why do I need an EMG? Are there any other options for diagnosing my condition?
Is this procedure covered by my insurance? Do I need pre-authorization? If it is not covered, how much does it cost? Is there financial assistance available to cover the cost?
How long will the procedure take? When can I go home?
What restrictions will I have after the procedure? When can I return to work and other activities?
Will I need a ride home?
How should I take my medications?
How will you treat my pain or anxiety?
When will I receive the results of my test?
What other tests or procedures might I need?
When should I follow up with you?
How should I contact you? Ask for numbers to call during and after regular hours.
Knowing what to expect after an EMG can help you get back to your everyday life as soon as possible.
How will I feel after an EMG test?
You may have mild drowsiness after an EMG test if you had sedative medications. It is unlikely that you will feel pain after an EMG. It is common to experience mild tenderness and bruising at the needle injection sites. Let your doctor know if you are uncomfortable.
You will probably resume your regular activities after your EMG, as recommended by your doctor.
When can I go home?
You may need to stay in the outpatient facility or hospital for a short period after your EMG. Your team will apply warm compresses to your injection sites to reduce pain.
You will not be able to drive for about 24 hours if you had sedation because you will still be drowsy. You will need a ride home from your procedure, and someone should stay with you for the first day.
When should I call my doctor?
It is important to keep your follow-up appointments after an EMG test. Contact your doctor for questions and concerns between appointments. Call your doctor right away if you have:
Difficulty walking or moving a body part normally
Numbness or tingling
Swelling, discharge, redness, or pain at the needle insertion sites