What are EMG and NCS?
Electromyography (EMG) and nerve conduction studies (NCS) are two tests used to help diagnose nerve and muscle disorders. EMG measures electrical impulses in the muscles and NCS measure the speed and intensity of electrical signals that travel along the nerves.
When are these tests helpful?
They are often used when a patient has symptoms such as muscle weakness, numbness, spasms, paralysis or pain. EMG is used to help evaluate or diagnose muscle diseases, Amyotrophic lateral sclerosis (Lou Gehrig’s disease), nerve compression, peripheral polyneuropathies, cervical and lumbar radiculopathies, generalized weakness, focal weakness. NCS are used to help evaluate or diagnose carpal tunnel syndrome, focal numbness or weakness, peripheral polyneuropathies, generalized weakness, Myasthenia gravis.
Why are these tests helpful?
Nerves send electrical signals to muscles, cuing them to contract or relax, and muscles produce electrical activity when they move. When injury or disease affects nerves or muscles, the electrical activity changes. EMG and NCS show those changes and help your physician make a diagnosis and determine treatment options.