Evoked Potentials

Beaumont performs five types of evoked potentials (EP) tests. They are BAEP, SSEP, VEP, ERG, and EOG. The test records specific sensory impulses from end organs and the body such as eyes, ears, and limbs. Thus, the EP testing evaluates conduction of sensory nerve impulses along the nerve pathway from the end organ to the brain centers.

What to Expect

  • Electrodes are applied to your scalp and other parts of the body.
  • The result of the stimulation to different parts of your body is plotted on a graph and interpreted by a trained physician.
  • A parent or guardian must accompany minors (children under age 17).

Brainstem Auditory Evoked Potential (BAEP)

BAEP evaluates the auditory pathway from the ear through the brainstem to the brain. A series of clicks or tones are delivered through earphones to each ear independently. The test lasts approximately one hour.

Adult Patient Preparation

  • No preparation for adults.
  • Please bring a copy of the most recent hearing test, if available.

Pediatric Patient Preparation

  • Bring a blanket, a favorite toy, a stuffed animal, a bottle and/or pacifier to help calm child and encourage sleep.
  • Schedule the appointment during the child's naptime.
  • On the morning of the appointment, wake the child two hours earlier than natural wake up time.
  • Do not let the child sleep before the test. Parents must keep the child awake in the car on the way to the appointment. This should make it easier for the child to sleep during BAEP testing.
  • If child is ill or has a fever, call as soon as possible to reschedule appointment.

Somatosensory Evoked Potentials (SSEP)

SSEP is used to evaluate the nervous system pathway(s) from nerves in the arms or legs through the spinal cord to the brain. A series of small electrical currents are applied to the skin at the extremity. The current creates a tingling and/or tapping sensation, but not pain. The patient needs to remain relaxed and comfortable during the testing. The test takes approximately 90 minutes to two hours.

Patient Preparation

  • If the test is being done on the lower extremities, please wear shorts for testing.
  • Please do not wear body lotion, powder, or hair styling products.

Visual Evoked Potential (VEP)

VEP takes about one hour to complete. VEP is used to evaluate the visual pathways from the eye to the visual cortex of the brain. Each eye is tested separately while you sit in a chair, alert and staring at the middle of a checkerboard pattern display on a video screen.

If you cannot fully cooperate to stare at the checkerboard pattern (i.e. a baby or small child) each eye will be tested separately using bright light flashes from a strobe light or from goggles worn over the eyes.

Patient Preparation

  • Please have clean hair without any hair styling products, braids or weaves.
  • Wear prescription glasses or contacts for test.

Electroretinogram (ERG), ElectroOculogram (EOG)

The ERG and EOG evaluate the retina in the eye. Each test lasts approximately one hour. During the test, your eyes are stimulated with various colors of flashing and flickering lights.

What to Expect

  • Your eyes are adapted for 30 minutes. The technologist will place three different eye drops in you eyes that will numb and dilate them.
  • Contact lenses are placed on your eyes and a couple of few recording electrodes on your scalp.
  • At the end of testing the contact lenses are removed, and eyes are rinsed with a sterile solution.
  • The patient needs to wear sunglasses when leaving the department.
  • Testing takes approximately one hour.

Patient Preparation

  • Please do not wear contact lenses or eye makeup for the ERG.
  • Do not use Pilo-Carpine eye drops for 24 hours before testing.
  • Bring sunglasses.