Wada Test The intracarotid amobarbital test or Wada test (named after Dr. Juhn Wada, its originator), is part of the presurgical evaluation in a patient who may have epilepsy surgery. A thin plastic tube ("catheter") is inserted into an artery at the groin and threaded into other arteries leading to the brain. The short-acting anesthetic agent sodium amobarbital is injected into an internal carotid artery (the large artery on the side of the neck going to the brain), thus putting that side of the brain "to sleep". The patient's ability to speak, understand speech, and remember things is evaluated. After the drug effect has worn off, the process is repeated with the other hemisphere. The Wada test requires a brief hospitalization. It helps us determine which cerebral hemisphere is "dominant" for speech and if memory is functional on one or both sides of the brain. If the seizures are coming from the nondominant hemisphere, this test may not be needed.