Electromyography and Nerve Conduction Studies: What to Know
Marie Walker MD, Physical Medicine & Rehabilitation Physician
Electromyography (EMG) and Nerve Conduction Studies (NCS) are essential medical tests that offer a path to understanding what is causing your pain, numbness/tingling, or weakness and can help your doctor determine the best treatment plan for you. Discover how EMGs and NCS studies work, what you can expect, and how they can help bring relief and clarity as you seek treatment for your orthopedic and neurologic conditions.
What is the Electromyography Study?
The Electromyography Study consists of two tests – the Electromyography Study (EMG) and the Nerve Conduction Velocity Study (NCV or NCS). The two studies together help detect the cause for muscle weakness, numbness, or pain.
The Difference Between the EMG Test and the NCS Test:
What is an EMG?
The Electromyography Test measures the electrical activity of the muscles.
What is an NCS?
The Nerve Conduction Study measures the speed and intensity of the electrical signals that travel along the nerves.
What Information Can the EMG Give You?
The EMG/NCS Studies test the peripheral nervous system. Through these tests, your physician can:
- Confirm the diagnosis of your condition.
- Localize the nerve lesion.
- Determine the severity of the nerve injury.
- Determine the time course of the problem, whether it is acute, subacute, or chronic.
- Distinguish between active and inactive (old) nerve damage.
- Rule out multiple superimposed peripheral nerve problems.
- Help determine pathophysiology such as the type of muscle disease or peripheral neuropathy.
Conditions and Diseases the EMG/NCS Test is Used to Diagnose
The EMG and NCS studies can identify nerve problems of the peripheral nervous system, which are nerves that are in your neck, back, arms, and legs. It cannot detect nerve damage in the brain or spinal cord.
Diagnoses or Conditions can include but are not limited to:
- Radiculopathy (cervical and lumbar)
- Carpal tunnel syndrome
- Ulnar neuropathies
- Foot drop
- Sciatica
- Muscle disorders
What to Expect During the EMG/NCS Study
How does the NCS Study Work?
You will be asked to lie down for the test. Recording electrodes will be placed on your arm or leg, depending on where you are having symptoms. Then a stimulating electrode will be held against your skin. Tiny electrical pulses will be sent through your nerves which are completely harmless. While this is taking place, responses will be recorded. This part of the test gives information about the function of the nerve and how well it is able to conduct its signal.
How does the EMG Study work?
During the EMG Study, you will also be asked to lie down while the test is taking place. A thin needle will be carefully placed into several muscles in the arm or leg, depending on where you are having symptoms. The needle has a recording electrode at the tip of it which records the electrical activity of the muscle. While these needles are inserted, you may feel pressure or a dull ache. Approximately 5-8 muscles per affected limb will be tested both at rest and while contracted. In order to test the muscles while they are contracted, your muscles will need to be slowly flexed or “worked”. This part of the test gives information about the nerves that go to the muscles.
Is the EMG/NCS Study Painful?
One misconception about the EMG and NCS studies is that the test is very painful. Although you may experience some discomfort or a dull ache during the test, most people find it to be very tolerable and not painful.
What happens if the EMG/NCS Tests are Positive or Abnormal?
The results of the test will be sent to your referring doctor who ordered the test. He/she will inform you of the results and what your treatment options are.
How to Prepare for an EMG/NCS Study
If you are required to have an EMG study done to help diagnose your condition, here are a few things to keep in mind when it comes to preparing for the tests.
- Make sure to shower on the day of your study.
- DO NOT use products on your skin such as lotions, creams, oils, or powders the day of the test
- You can take all your regular medications, including blood thinners.
- Notify your doctor if:
- You bruise easily or are on blood thinners
- Have a skin infection
- Have diabetes
- Have a pacemaker
- Have a spinal cord stimulator
What to Expect After an EMG/NCS Test
The muscles tested may be sore for a few days. Ice, heat, ibuprofen or Tylenol are ok to use to help with the pain until the discomfort subsides.
How Long Does the EMG/NCS Study Take?
The length of the EMG/NCS study will vary for each patient, however, you can expect that the test will take approximately 30 minutes to an hour. The first 10 minutes will consist of warming and the last 20-45 minutes will be when the tests are conducted.
When Can I Expect Get the Results of My EMG/NCS Study and Who Will Provide Me With the Results?
The report will be sent to your referring doctor who will relay the results of the test to you and provide recommendations for the next step in your treatment plan.
Electromyography and Nerve Conduction Study Cost
EMG/NCS are covered by all insurances. There is no copay. However, if you have not met your deductible, there will likely be some out-of-pocket expenses you will be responsible for. The amount you are responsible for is dependent on your insurance.
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Understanding the importance and process of EMG and NCS can significantly impact your journey towards better health. These tests are essential for diagnosing the cause of pain, numbness, or weakness, and they play a crucial role in determining the best treatment plan for you.
If you or someone you know is experiencing unexplained symptoms, don’t hesitate to discuss these tests with your healthcare provider. Taking proactive steps now can lead to a clearer diagnosis and more effective treatment plan.
Not only does OSMS offer EMGs as a diagnostic service, but we also have onsite MRI, X-Ray, CT scans and more. Learn more about our diagnostic services at: Experience Faster Care at OSMS with Onsite Treatment and Technology.
To schedule an appointment at OSMS, where our physicians can help you receive care to a more streamlined recovery, visit: Schedule an Appointment – OSMS
