Electromyography (EMG) and Nerve Conduction Studies (NCS)
Electromyography (EMG) and nerve conduction velocity studies (NCV or NCS) are electrophysiologic tests that measure the electrical activity of muscles and nerves. These tests may be an important part of a spine patient’s work-up by their doctor. Besides back pain or neck pain, some patients with spine-related problems report symptoms of numbness and/or tingling sensations, muscle cramping, or weakness in the limbs. EMG & NCS can help to help determine why and where those symptoms are occurring.
EMG/NCS tests are performed by Physiatrists and Neurologists. Both tests are often performed at the same appointment. EMG/NCS may help your doctor successfully identify your muscle and/or nerve related spine pain. Once a diagnosis is made, you and your doctor can discuss your treatment options to reduce your pain and restore function. EMG/NCS testing may be used to determine:
- If the problem is related to nerves or muscles
- The presence of nerve damage
- The cause of nerve damage
- The location of nerve or muscle damage
- Whether damaged nerves are healing
Your doctor will analyze the results of the test(s) and send a written report to your referring doctor.
- You have an implanted pacemaker or other medical device
- You take blood-thinning medication
- Have a bleeding disorder
Electromyography (EMG): What It Is and What to Expect
EMG measures muscle response to nerve stimulation and evaluates electrical activity within selected muscles. This test may help differentiate between a muscle disorder and a nerve disorder and where the source of the nerve problem is located which can help your doctor make an accurate diagnosis. During an EMG, a thin needle is inserted through your skin into specific muscles. Electrical impulses are recorded on a digital screen as waves. Additionally, the doctor will listen to the muscles through a speaker.
Nerve Conduction Study (NCS): What It Is and What to Expect
NCS measure the speed at which an electrical impulse travels along a nerve. During NCS patch-like electrodes are applied to your skin over the nerve to be tested. Low-level electricity is used to stimulate the nerve. The amount of electricity is similar to a shock from static electricity. The nerve impulses are displayed as waves on the computer screen and the velocity at which the electrical signal flows through the nerve can be calculated.
EMG and NCS: Discomfort and Risks
- EMG: You may feel discomfort when the needle electrodes are inserted.
- NCS: You may feel startled when the electrical pulses are applied.
- After EMG: The muscle(s) tested may feel sore and you may have minor bleeding or bruising where the needles were inserted.
- EMG risk: Very small risk of infection where the needles were inserted.