Evoked Potentials

Grazyna Piekos, M.D.
Board Certified in Neurology, Sleep Disorder Medicine and Clinical Neurophysiology

Evoked Potential (EP) tests are used to check the condition of the nerve pathways. They measure the brain's electrical response to the signals sent by the nerves. EP tests help diagnose nervous system abnormalities, hearing loss, and assess neurological functions.

Major Types of Evoked Potentials (EP) Tests

	Brainstem Auditory Evoked Potential - Checks the pathway from the ear to the brain. The BAEP test may help uncover the cause of hearing and balance problems, and other symptoms.
	Visual Evoked Potential - Checks the pathway from the eyes to the brain. May help find the cause of certain vision problems and other conditions.
	Somatosensory Evoked Potential - Checks the pathway from the nerves in the limbs to the brain. It is a way to study the function of the nerves, the spinal cord and brain.

Preparation

	Wash your hair the night before the test. Do not use any oils or lotions.
	Eat a normal meal at your usual mealtime before the test.
	Avoid caffeine.
	Bring glasses or contact lenses if you will be having a VEP test.

Procedure

	Positioned on a reclining chair or bed and asked to relax, remain still.
	Electrodes placed on your scalp, along the vertex and on each earlobe.
	A mild stimulus is applied to the eyes, ears or limbs.
	Clicking noises or tone bursts heard through earphones.
	The electrodes pick up the brain's response and records it on a graph.

How It Feels

	There is little discomfort during the procedure.
	They are usually performed within an hour, and are painless and safe.

Evoked Potentials

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