Electromyography (EMG) and Nerve Conduction Study

Nerves and muscles naturally produce electricity. An electromyography (EMG) and nerve conduction study measures the electrical activity created by your muscles and nerves to determine if they are healthy.

Some nerve and muscle issues (also called "neuromuscular") may be difficult to diagnose. Often, a physical exam and/or blood tests alone cannot provide a diagnosis. An EMG and nerve conduction study can help.

Conditions and Symptoms Diagnosed With EMG at Rush

An EMG and nerve conduction study can help diagnose the following conditions and symptoms:

Amyotrophic lateral sclerosis (ALS)
Carpal tunnel syndrome and other entrapment neuropathy
Diabetic neuropathy
Peripheral neuropathy
Muscular dystrophy
Myasthenia gravis
Radiculopathy
Numbness or loss of feeling
Tingling
Muscle weakness
Muscle pain, cramping or twitching

EMG and Nerve Conduction Study: What to Expect at Rush

The test typically has two parts that are performed in the same setting: the nerve conduction study and electromyography study.
The entire test usually takes about 1.5 hours total. It may be shorter or longer depending on your condition.

Nerve Conduction Study

Rush technicians or doctors will place electrodes on your skin. They will place these over nerves and muscles that may be involved in causing your symptoms.
They will then stimulate the nerves, one at a time. They are looking for your nerve or muscle's response.
They compare the responses to what is considered "normal" to determine the health of your nerves and muscles.

EMG

Rush technicians or doctors will insert a thin needle electrode into muscles, one at a time, that may be involved in your symptoms.
They will then ask you to either relax or activate the muscles. For example, they may ask you to relax or bend your elbow, relax or push down with your foot, etc.
Your doctor will use these actions to analyze your muscles when they are at rest or being active.

Is an EMG or Nerve Conduction Test Painful?

Your technician or doctor will make every effort to minimize any discomfort you may experience. Most patients do not experience significant discomfort or side effects.

Nerve conduction study: These feel like static electricity or like a rubber band slapping against your skin. You may feel your muscles twitch.
EMG study: You may feel some discomfort or pain when the doctor inserts the needle into the muscle.
Potential side effects: There may be bruising and/or soreness of the muscle for one or two days after the test.

EMG and Nerve Conduction Study Test Results

The doctor who performs your test may be able to explain some of your test results before you leave. But this is not always possible. These tests are highly technical and often need to be thoroughly reviewed by the doctor who ordered them before a final conclusion.
After your test, the next step is to follow up with the doctor who ordered the tests. You'll discuss your condition, treatment options and any further testing needs with them.