EMG & NCV Studies

What is an NCV?

NCVs are used to evaluate the speed of nerve conductions by measuring the electrical signals. During the test, small electrodes will be applied to your limbs and a small electrical current will be applied to measure the nerve response. Several nerves may be studied.

What is an EMG?

An EMG measures muscle response of electrical activity in response muscle movements. During the test, small needle electrodes are inserted through the skin into the muscle. The electrical activity is measured by electrical activity of muscle during rest, slight contraction and forceful contraction.

Who is appropriate for NCV/EMG testing?

Electrodiagnostic testing is used to help diagnose neuromuscular abnormalities and injuries for symptoms such as numbness, and weakness as well as some types of pain. This will give more information on what nerves or muscles are affected and to what extent.

Your doctor may order an NCV and/or EMG if you have signs or symptoms that may indicate a nerve or muscle disorder. Such symptoms may include:

• Tingling/ Numbness
• Muscle weakness
• Muscle pain or cramping
• Certain types of limb or spinal pain

NCV/EMG studies are often necessary to help diagnose or rule out a number of conditions such as:

• Disorders that affect the spinal nerve root, such as a herniated disk in the spine and nerves of the spinal roots
• Disorders of nerves outside the spinal cord (peripheral nerves), such as carpal tunnel syndrome or peripheral neuropathies
• Muscle disorders such as myopathy, myasthenia gravis and congenital disorders
• Disorders that affect the motor neurons in the brain or spinal cord

What to expect during a NCV/EMG test?

When you arrive at our office, you’ll be escorted to an examination room and asked to either sit or lie down for the test. One of our Physical Medicine and Rehabilitation physicians will do a focused exam and locate the nerves and muscles to be studied. Electrodes will be placed for testing and then you will have stimulation to test the nerves for NCV. Then, a fine, sterile needle electrode will be inserted into the muscle. You will be asked to relax and then perform slight or full-strength muscle contractions as the response is measured. This may be uncomfortable but is not usually painful and most exams are about 30 minutes in duration.