Wada Evaluations & Cortical Stimulation Procedures


Contributed by Thomas G. Burns, Psy.D., ABPP/ABCN

The wada test is a highly specialized procedure that is part of the neuropsychological examination in most comprehensive epilepsy centers. It is a test that enables the clinician to determine cerebral dominance and to evaluate memory function in each hemisphere of the brain. The procedure may be requested by an epileptologist in order to obtain more detailed information about the patient's memory abilities.

This evaluation is conducted on an outpatient basis. The neuropsychologist, neurologist, EEG technician, intervention neuroradiologist, and nursing staff are all present for the procedure and the patient is typically able to go home that same day. This test is often used for children who are surgical candidates and may have been diagnosed with intractable epilepsy or a brain tumor. As a result of this information, the neuropsychologist and neurologist are then able to help the epilepsy team make a final decision regarding surgery.

Cortical stimulation procedures are often utilized prior to surgery to assist the neurosurgeon in making surgical decisions regarding the precise area of the brain that is effected by seizures. This process involves the placement of a grid, which is an array of electrodes, that will measure the electrical activity on the surface of the brain. The neurologist and neuropsychologist then determine if there are speech and/or motor changes while the electrodes are stimulated. This helps to identify and better understand certain areas of the brain that will help the neurosurgeon identify what functions are associated with the specific area of the brain.