Electromyography (EMG), sometimes called an electromyogram, is a specialized diagnostic test used to assess the electrical activity of muscles. This test helps doctors diagnose and evaluate muscle and nerve conditions, providing crucial insights that guide treatment decisions.
At UPMC, we use the latest technology and techniques to ensure accurate diagnoses and comprehensive, multidisciplinary care. Our goal is to reduce symptoms, improve function, and enhance your quality of life.
What Is Electromyography (EMG)?
Electromyography is a diagnostic procedure that records and analyzes the electrical activity in your muscles. The test involves inserting small electrode needles into targeted muscles to assess how well the muscles and nerves communicate.
A healthy nervous system sends electrical impulses that allow muscles to function properly. When there is nerve or muscle dysfunction, these electrical signals may be disrupted, leading to symptoms such as weakness, numbness, tingling, or pain.
Why is electromyography performed?
EMG helps diagnose a variety of conditions that affect the muscles and nerves, including:
- Carpal tunnel syndrome – A condition caused by compression of the median nerve in the wrist.
- Focal nerve injuries – Damage to specific nerves, often due to trauma or repetitive strain.
- Muscle disorders – Conditions such as multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease).
- Nerve injuries in the neck and back – Including radiculopathy caused by herniated discs or spinal stenosis.
- Neuromuscular diseases – Disorders that affect the nerves and muscles, impairing movement and function.
- Peripheral neuropathies – Conditions such as muscular dystrophy that involve damage to peripheral nerves.
Who is a candidate for electromyography?
You may be a candidate for EMG if you experience:
- Muscle weakness that affects your daily activities.
- Persistent numbness or tingling in your limbs.
- Pain, discomfort, or loss of coordination in your hands or feet.
- Unexplained muscle cramps, spasms, or twitching.
Your doctor may recommend an EMG to confirm a diagnosis or rule out other conditions affecting your nervous system.
Alternative diagnostic tests
In some cases, EMG is performed alongside a nerve conduction study (NCS), which evaluates how well electrical signals travel through the nerves. These tests are often conducted in the same appointment to provide a more comprehensive evaluation.
What Are the Risks and Complications of Electromyography?
EMG is a safe procedure, and complications are rare.
However, some patients may experience:
- Mild discomfort during needle insertion.
- Minimal risk of infection or bleeding at the electrode insertion points.
- Temporary soreness or bruising at the test site.
If you have a bleeding disorder or take blood-thinning medications, inform your doctor before the test.
How to Prepare for Your EMG Test
Before the electromyography
Before your procedure, your care team will conduct a physical exam and may order additional tests, including:
- Blood and urine tests – To check for underlying conditions that could affect the procedure.
- CT scan – A detailed imaging test to assess bones, discs, nerves, and tissues.
- MRI – A noninvasive imaging technique that provides detailed views of internal structures.
- X-ray – Used to examine bones and soft tissues in the affected area.
To ensure the best possible results, follow these preparation guidelines:
- Medical history – Inform your doctor about any allergies, medications, or underlying health conditions.
- Medications – Discuss whether you need to adjust blood.
- Personal belongings – Bring your photo ID and health insurance card, but leave valuables like cash or jewelry at home.
- Skin care – Avoid applying lotions or oils to your skin on the day of the test, as they may interfere with electrode placement.
- Transportation – While not required, you may want to arrange for someone to drive you home after the test.
During electromyography
When you arrive at the hospital, your care team will guide you through final preparations. You will remain awake and may be asked to sit or lie down.
Your doctor will:
- Insert a small electrode needle into the targeted muscle.
- Ask you to relax and contract the muscle in specific ways.
- Measure the electrical activity and record the data.
- Move the needle to test multiple muscles as needed.
Does an EMG hurt?
You may experience mild discomfort when the needle is inserted, but the test is generally well-tolerated. Some patients report minor soreness in the tested muscles for a day or two following the procedure.
How long does an EMG take?
The entire procedure typically lasts 60 to 90 minutes, depending on the number of muscles being tested. Each individual muscle test only takes a few minutes.
Recovery and aftercare
- You will be monitored briefly after the procedure to ensure you feel well.
- You can resume normal activities immediately unless instructed otherwise.
- Minor bruising or tenderness at the test site is normal and should resolve within a few days.
When to call your doctor
Contact your doctor if you experience:
- Fever above 100.0°F.
- Severe pain or swelling at the test site.
- Signs of infection (redness, warmth, pus).
- Unusual weakness or worsening symptoms.
Why Choose UPMC for Your EMG?
At UPMC, we provide expert diagnostic services and state-of-the-art technology to ensure the most accurate results.
Our specialists are highly trained in diagnosing and treating all types of muscle and nerve disorders, offering:
- Minimally invasive techniques to ensure comfort and safety.
- Advanced diagnostic tools for precise and reliable assessments.
- Comprehensive, multidisciplinary care tailored to your condition.
- Cutting-edge research and clinical trials to bring the latest advancements to our patients.
From diagnosis to treatment and recovery, our team is dedicated to helping you regain function and improve your quality of life.
By UPMC Editorial Staff. Last reviewed on 2025-06-26.
