Electrodiagnostic Testing (EMG)

What is Electrodiagnostic testing ?

An electrodiagnostic study (EMG) is a test that checks to see how well your nerves and muscles are working. It has 2 main parts:

  1. Nerve Conduction Studies (NCS): tests how well your nerves send electrical signals

  2. Needle Electromyography (EMG): tests how well your muscles respond to signals from nerves

Indications

Electrodiagnostic testing is commonly used to help diagnose

  • Carpal tunnel syndrome

  • Peripheral neuropathy (nerve damage in hands and feet)

  • Radiculopathy (pinched nerves in back or neck)

  • Muscle diseases

  • Motor neuron diseases

Before the Procedure

  • Do not apply creams, lotions or perfumes to your skin for 2 days before the test.

  • Tell your doctor if you have a pacemaker or cardiac defibrillator.

  • If you are prone to cold hands or feet, make sure to warm them before the test.

During the Procedure

Electrodiagnostic testing is minimally invasive and is done on the same day in an outpatient setting.

Part 1 - Nerve Conduction Studies

  • Small, flat electrodes are places on your skin over certain nerves

  • Brief, mild electrical impulses are sent through the electrodes to stimulate the nerve.

  • The machine records the speed and strength of the nerve signal.

This process is repeated at several spots. You will feel a light tapping or tingling sensation during the test.

Part 2: Needle EMG

  • Your doctor will insert a very thin needle electrode into specific muscles.

  • The machine listens to and records the electrical activity in the muscle while it is at rest and while you gently contract it.

The needle may be moved to test several muscles. You may feel a brief pinch while the needle is placed, but most patients tolerate this well.

This test generally takes 30-60 minutes, depending on the areas being studied. Your doctor will tailor the test based on the results, so the exact muscles and nerves tested will vary from patient to patient.

Post Procedure

  • You can return to normal activities immediately after the test.

  • You may have mild soreness or small bruises at the needle site. This is normal and will resolve in a few days.

  • Your doctor will review the results and discuss the findings with you.

When to call your doctor

Contact your doctor if you experience any of the following after the procedure

  • Fever or chills

  • Severe or worsening pain

  • New weakness or numbness in your arms or legs

  • Difficulty with bowel or bladder control

  • Redness, swelling, or drainage at the injection site

  • Significant bruising that continues to spread

Frequently Asked Questions

  • Yes. Since no sedation is used, you can drive yourself to and from the appointment.

  • Your doctor will review the results with you either immediately after the test or at a follow-up appointment.

  • EMGs are commonly used to evaluate symptoms like numbness, tingling, weakness, or pain that may be related to nerve or muscle conditions such as pinched nerves, carpal tunnel syndrome,

  • Some patients experience mild soreness or slight bruising at the needle insertion sites, which typically resolves within a day or two.

  • No. Sedation is not used for EMG testing, as your doctor needs you awake and able to follow instructions.

  • Depending on what the EMG shows, your doctor may recommend further imaging, physical therapy, medication, or other treatments, such as injections.