Evoked Potential Tests
An evoked potential test measures the response of the brain to various kinds of stimulation. These responses are plotted on a sheet of paper and reviewed by a neurologist, who is a physician specializing in conditions of the nervous system. Nerves from different areas of the body may be tested through the three kinds of Evoked Potential Tests– Visual Evoked Potential (VEP), Brainstem Auditory Evoked Potential (BAEP), and Somatosensory Evoked Potential (SSEP). Although not a treatment, the tests will contribute to your total medical evaluation. Depending on what and how many tests are ordered, they can take anywhere from 45 minutes to 3 hours.
What takes place prior to the tests?
You will be given a time and date to return to this office for your testing. Your hair and scalp should be clean and free of oils and hairspray. Also, do not use any oils, creams or lotions on your arms or legs the day of the testing. When you come here for your evoked potential testing you will be placed in a comfortable room. The examining technician will measure and mark your head to ensure accurate placement of the small metal discs that will be placed with a paste-like substance on your scalp. This paste will be completely removed after the tests. Some stick-on electrodes may also be placed on your body.
What happens during a Visual Evoked Potential Test (VEP)?
If you are having a Visual Evoked Potential Test, you will be asked to focus on the center of a checkerboard pattern that is shifting back and forth. You will have one eye tested at a time and will need to be as alert as possible. Please bring your usual eye glasses, contact lenses etc. with you.
What happens during a Brainstem Auditory Evoked Potential Test (BAEP)?
If you are having a brainstem auditory evoked potential test, you will have a brief hearing test, followed by a series of clicks in each ear, one at a time. You may relax and even fall asleep during this test if you wish.
What happens during a Somatosensory Evoked Potential Tests (SSEP)?
If you are having a Somatosensory Evoked Potential Test, you will feel a slight tingling in your hand or foot that may cause your fingers or toes to wiggle. You should relax as much as you can. Also, you should wear loose comfortable clothing that can be lifted above the knee or shorts if you prefer.