Preparing for EEG and EMG Testing

EEG Preparation


An electroencephalogram (EEG) is a test that measures and records the electrical activity of your brain through electrodes attached to the scalp with paste. It is a noninvasive test that is particularly useful for diagnosing seizures, it is also useful for diagnosing a number of other conditions.

To insure accurate test results, please follow these guidelines:

  • Wash your hair the night before or the day of the test, but do not use conditioner, or other hair products.  Some patients like to bring a comb or brush to use after the test.
  • Do not consume caffeine containing beverages or foods for at least 6 hours prior to testing.  (Non-caffeinated teas and coffees are okay)
  • It is not necessary to fast for this test.  Please eat your normal meal before the test, just refrain from caffeine.
  • If you are scheduled for a sleep deprived EEG: No more than 4 hours of sleep the night before the test.  We suggest you go to bed at midnight and wake up at 4 a.m.  DO NOT NAP BEFORE THE TEST!!
  • Take your normal medications unless instructed otherwise.

Nerve Conduction Studies (NCS) and Electromyograms (EMG)

How to prepare:

  • On the day of your test, bathe or shower, washing your arms and legs well to remove body oils. Do not use any bath oils, lotions or powders as they can interfere with testing.
  • Inform your provider if you are currently taking blood thinners or have a pacemaker.
  • Wear loose fitting clothing. You may be given a gown to wear if necessary.

What to expect:

During the NCS small electrodes will be placed over the muscle supplied by the nerve  being studied. Repeated, brief electrical pulses are administered to the nerve, and the muscles response to the electrical pulse is recorded. The speed of the response is used to calculate the conduction velocity. Your muscles will twitch, but the test won’t harm you.

With the nerve conduction study, you will feel a brief, burning/tingling sensation, and a twitching of the muscle each time the pulse is applied.

The EMG assesses muscle function. The doctor will clean the area being tested with alcohol, then a fine needle will be inserted. This allows the electrical activity in your muscle to be tested. When the needle is inserted, you may feel a slight pinch.

These tests are used to find or rule out diseases that damage muscle tissue, peripheral nerves, or the junctions between nerve and muscle.