Evoked potential studies are performed to evaluate and measure the electrical activity that occurs in the brain in response to specific stimulation to the nerves responsible for sight, sound and touch sensations. Although these tests are not designed to provide a confirmed diagnosis of a condition, they can be useful in providing additional information that can aid in diagnosis and in determining if additional testing is needed.
There are three types of evoked potential studies:
Visual evoked potential (VEP) tests to evaluate the optic nerve to help diagnose or assess problems with vision. During the test, electrodes are attached to the scalp and the patient will be asked to focus on images on a screen located a few feet away. As different images flash across the screen, the brain’s electrical activity will be measured.
Brainstem auditory evoked response (BAER) tests are used to evaluate symptoms related to hearing as well as help diagnose brain tumors and multiple sclerosis. During the test, electrodes are placed on the scalp and earlobes, and the patient wears special headphones. A series of clicking noises are transmitted to the headphones and brain activity is evaluated as the sounds occur.
Somatosensory evoked response (SSER) tests are used to evaluate issues affecting the spinal cord and the peripheral nervous system. During the test, electrodes are placed on the scalp and elsewhere on the body. Tiny electrical impulses are transmitted to the electrodes on the body while the scalp electrodes record the brain activity.
Although they usually don’t lead to a specific and definitive diagnosis, evoked potential studies can provide very important information about symptoms a person may be experiencing, helping to detect issues affecting vision, hearing or the central nervous system. They’re often used to help confirm a diagnosis of multiple sclerosis, and they can also be helpful in identifying issues affecting the optic nerve or central nervous system, including the detection of tumors.