Electrodiagnostic Testing

What Is Electrodiagnostic Testing?

Electrodiagnostic testing refers to a group of tests that measure the electrical activity of muscles and nerves.
It helps doctors figure out how well your nerves send signals and how well your muscles respond.

The two main parts are:

1. Nerve Conduction Studies (NCS)

2. Electromyography (EMG)

 1. Nerve Conduction Studies (NCS)

• Goal: To check how fast and strong electrical signals travel through a nerve.

• How it works:

  • Small surface electrodes are placed on your skin over specific nerves and muscles.

  • The nerve is gently stimulated with a small electric pulse.

  • The response is measured and displayed on a screen.

What it tells us:

• If a nerve is damaged or pinched (like in carpal tunnel syndrome or sciatica).

• Whether the problem is with the nerve covering (myelin) or the inner nerve fiber (axon).

 2. Electromyography (EMG)

• Goal: To look directly at how muscles behave electrically.

• How it works:

  • A very thin needle electrode is inserted into a muscle.

  • The machine records electrical activity when the muscle is at rest and when it contracts.

What it tells us:

• If the muscle itself is diseased (like in muscular dystrophy).

• If the nerve supplying it is not working properly (like in radiculopathy from a herniated disc).