Nerve conduction studies are performed to:
Assess disorders of the peripheral nervous system which includes the nerves that lead away from the brain and spinal cord and the smaller nerves that branch off from those nerves. Nerve conduction studies are often used to help diagnose nerve disorders such as pinched nerves, carpal tunnel syndrome or Guillain-Barr syndrome.
Both EMG and nerve conduction studies can help diagnose a condition called post-polio syndrome that may develop months to years after a person has had polio.
How is the Procedure Performed?
In this test, several flat metal disc electrodes are attached to your skin with tape or a special paste. A shock-emitting electrode is placed directly over the nerve and a recording electrode is placed over the muscles under control of that nerve. Several quick electrical pulses are sent to the nerve. The time it takes for the muscle to contract in response to the electrical pulse is then recorded. The speed of muscle contraction response is called the conduction velocity.
Nerve conduction studies are done before an EMG if both tests are being performed. Nerve conduction tests may take from 15 minutes to 1 hour or more, depending on how many nerves and muscles are studied.