Evoked potentials (EP) tests measure the electrical activity in the brain in response to stimulation of touch, sight, or sound.
During an evoked potentials test, electrodes are placed on the scalp and other parts of the body to record these electrical signals for a doctor to interpret.
There are three major types of EP tests:
- Brainstem auditory evoked response test (BAER) – Clicks or tones are delivered to each ear to evaluate the auditory nerve pathways from the ears through the brainstem.
- Somatosensory evoked response (SSEP) – A small, painless electrical current is applied to the skin to evaluate neural pathways from the arms or legs to the spinal cord to the brainstem or cerebral cortex.
- Visual evoked response test (VEP) – A checkerboard pattern is shown on a video screen to evaluate the visual nerve pathways from the eyes to the occipital cortex of the brain.
EP tests takes about 1 to 1.5 hours to complete.
Evoked potentials may also be continuously monitored during a neurosurgical procedure to help guard against nerve damage.
Evoked potential (EP) tests may be used to diagnose the following conditions:
- Optic neuritis
- Acoustic neuroma
- Multiple sclerosis
- Other neuromuscular and neurological diseases
EP tests may also be used to evaluate brain function during a coma.
You may be a good candidate for evoked potential (EP) tests if you are having symptoms of a neuromuscular or neurological disease.
It is considered a safe procedure and causes little discomfort. Certain conditions, such as severe hearing impairment or nearsightedness, may affect your results.
Your doctor will help you decide if evoked potential testing is right for you.