Evoked Potential Tests show how well the body’s electrical signals travel through the sensory pathways of the nervous system in response to a specific external stimulus. Hundreds of responses are received, amplified and averaged by a special computer, and the final averaged response is plotted on a graph in the form of a wave or waves, which are evaluated by the neurologist.
VER (Visual Evoked Response)
Visual Evoked Responses evaluate the visual nervous system. Five electrodes are attached to the scalp. The patient will focus on a checkerboard pattern on a computer monitor. The checkerboard pattern is the stimulus and the recording is made through the scalp electrodes. If you wear glasses or contact lenses, you need to wear them during the test.
BAER (Brainstem Auditory Evoked Response)
Brainstem Auditory Evoked Responses evaluate the auditory nervous system including the brainstem. Two electrodes are attached to the scalp and one on each earlobe. Earphones are then placed over the ears and a series of clicking sounds are delivered to each ear separately. The clicking sound is the stimulus and the recording is made through the scalp electrodes.
SSEP (Somatosensory Evoked Potential)
Somatosensory Evoked Potentials evaluate the nerve pathways from the peripheral nerves through the spine to the somatosensory region of the brain (somato-body, sensory-reception). Electrodes are attached to the scalp as well as various points along the nerve pathway from arm or leg to the brain. A small electrical current is applied to the skin over a nerve on the arms or legs and the recording is made through the attached electrodes.
SSEP-arms (Median/Ulnar Nerve Somatosensory Evoked Potential)
Electrodes will be placed on the shoulders near the neck area, on the back of the neck, and head. Please wear an open-necked top with short sleeves. DO NOT use body lotion on your arm or neck.
SSEP-legs (Posterior Tibial Somatosensory Evoked Potential)
Electrodes will be attached to your legs, back and head. Please bring shorts/skirt to wear during testing. DO NOT use body lotion on your legs or back.
Click here for full instructions on how to prepare for these tests.