What is an EMG/NCS?

NCS stands for nerve conduction studies, and is the first portion of the test typically done before the EMG, where the nerves themselves are tested. An electromyography (EMG) is a technique used to measure the electrical activity of muscles both at rest and during contraction. An EMG detects the electrical potential generated by muscle cells when the cells are electrically or neurologically activated.

Why is it done?

  • To find diseases that damage muscle tissue, nerves or neuromuscular junctions (junctions between nerve and muscle).
  • To find the cause of weakness, paralysis or muscle twitching, numbness and tingling.

Diseases that can be detected with an EMG/NCS:

  • “Pinched” nerves (sometimes caused by disk herniation in the spine)
  • Carpal tunnel syndrome
  • Neuropathy
  • Amyotrophic lateral sclerosis (ALS)
  • Myasthenia gravis (MG)