Prior to your test, shower or bathe as normal and wash your hair. Do not apply hair gel, styling products, oils or hairspray, and avoid the use of hair pieces or weaves. Wear loose, comfortable clothing.
You will be asked some general health questions. The test will be done in a quiet room. Each part of the test will be explained to you. There are several different types of Evoked Response tests, but you will only have those ordered by your physician.
Visual Evoked Response (VER)
You will be seated a few feet away from a computer screen for this test. The technologist will prep your skin and place several electrodes on your scalp with a paste. You will be asked to look at the screen, one eye at a time, while watching a checkerboard pattern. This test takes about 30 minutes.
Brainstem Evoked Response (BAER)
You will lie down for this test. The technologist will prep your skin and place several electrodes on your scalp with a paste. You will wear a set of headphones that will deliver a clicking noise in each ear while the technologist takes a reading. This test takes about 30 minutes.
Somato-Sensory Evoked Response (SER)
You will lie down for this test. Electrodes will be placed on your head, arms, legs or spine. The technologist will attach a stimulator to your wrist and/or ankle. You will feel a tingling sensation that will make your muscle twitch. This test takes about 45 minutes.
Each stimulus is received by sight, sound or touch. The technologist will collect and record the signals from your brain to check the signals your brain receives from a point in your body. Once these signals are recorded, they will be studied to determine the results. Your results will be given to you by your doctor.