EMG, or Electromyogram is a test used to record the electrical activity of muscles. Active muscles produce an electrical current that is usually proportional to the level of muscle activity.

The intramuscular EMG is the test most commonly administered.  It can detect abnormal muscle electrical activity in many diseases and conditions, including inflammation of muscles, pinched nerve, damage to nerves in the arms and legs, disc herniation, and degenerative diseases such as muscular dystrophy, Lou Gehrig’s disease, Myesthenia gravis, among others.

In the NCV (nerve conduction velocity test), the nerve is stimulated in order to calculate the speed of impulse transmission or the nerve conduction velocity.  A decreased speed of nerve conduction indicates nerve disease.

The NCV test is often done at the same time as the EMG in order to exclude or detect both nerve and muscle conditions. It may indicate damage to a nerve from trauma, diabetic or peripheral neuropathy, herniated disc, polyneuropathy, or myasthenia gravis or Guillain-Barre Syndrome, among other things.