Evoked Potentials Study
An evoked potentials study measure electrical activity in the brain in response to stimulation of sight, sound or touch. This test may be used to assess a child’s hearing and sight, or it can help diagnose brain and spine problems.
Evoked potentials studies can include three tests:
- Visual evoked response (VER) test. This test can diagnose problems with the optic nerves that affect sight. Electrodes are placed along the scalp. Your child will be asked to focus their gaze on the center of a screen. They will then be asked to close one eye at a time while the screen displays a checkerboard pattern.
- Auditory brainstem response (ABR) test. This test can diagnose hearing loss and can indicate the presence of brain stem tumors and multiple sclerosis. Your child will sit in a soundproof room and be asked to wear earphones. Electrodes will be placed on top of his or her head and on one earlobe at a time. A clicking sound or other sound will be delivered through the earphones to one ear while a “masking” noise will be delivered to the other ear to shield it from the sound.
- Somato-sensory evoked response (SSER) test. This test can detect problems with the spinal cord as well as numbness and weakness of the extremities. Electrodes will be placed on your child’s scalp and at one or more locations on the body, such as the wrist, back of the knee or the lower back. Small, painless electrical shocks will be delivered through the electrodes.
Once the test is complete, the electrodes will be removed and the electrode paste washed off. In some cases, you may need to wash your child’s hair again at home.
How should I prepare my child for an evoked potentials study?
Consider the following when preparing your child for an evoked potentials study:
- Wash your child’s hair the night before the test, but do not use any conditioner or apply any hair products.
- Unless otherwise directed, give your child his or her medications as usual. Bring a list of all the medications (dose and schedule) your child takes to the Neurodiagnostics Lab.