What is it?
Evoked potentials are used to diagnose diseases of the nervous system, such as multiple sclerosis. They can give important information about the brain and spinal cord, and about the nerve pathways leading to it from the eyes and ears. How is the test performed?
If light is flashed in the eye or a small electrical pulse given to the skin over a nerve in an arm or leg, a characteristic response - the evoked potential - can be recorded from the brain using electrodes placed on the scalp.
There will be a very short delay - measured in fractions of a second - between the delivery of the stimulus and the appearance of the electrical response in the brain. This delay corresponds to the time that it takes for the signal to pass from the eye or skin to the brain, along the nerve pathways.
Three types of evoked potential testing are commonly used: visual evoked potentials, auditory evoked potentials and somatosensory evoked potentials. What can the test tell my doctor?
If there is a delay in the appearance of the evoked potential in the brain, this may mean that something is wrong somewhere in the nerve pathways. Are there risks?
An evoked potential test has no lasting effects and will not have an impact on any of your regular activities. Your doctor will advise you of the test results after they have been read and analyzed. Sources:
-- Milton S. Hershey Medical Center College of Medicine
-- Brain and Spine Foundation Online