Electromyography (EMG)

Electrodiagnostic testing assesses the health of muscles and the motor neuron nerve cells that control them. Motor neurons are responsible for transmitting signals from the spinal cord to muscles, enabling muscle contraction.

Electrodiagnostic testing results can reveal nerve dysfunction, muscle dysfunction, or problems with nerve-to-muscle signal transmission.

This procedure usually involves two different tests:

  • nerve conduction study (NCS), which is also known as a nerve conduction velocity (NCV) test
  • An electromyography (EMG) diagnostic procedure

The length of electrodiagnostic testing can range from 1 to 3 hours, based on the underlying clinical problem.

Electromyography Diagnostic Procedure

Electromyography examines and measures electrical activity in muscles. It involves lightly inserting very thin gauge needles into a patient’s muscle. These needles are then connected to a computer, which records the electric impulses created by the body when the muscle is at rest and when a patient flexes the muscle.

A doctor then analyzes the recorded signals to determine whether there may be muscle or nerve damage. A number of different muscles may be examined this way, based on the clinical problem.

Video Overview: Electromyography (EMG)