The Wada test was named after Dr. John A. Wada. The purpose of the Wada test is to examine language and memory in each half (or "hemisphere") of the brain, separately. We do this by putting one half of the brain "to sleep" and seeing what the other half of the brain can do. The time during which half of the brain is "asleep" is only several minutes. The way we do this is by injecting amobarbital into the blood vessels that supply that half of the brain. A physician and neuropsychologist then examine you and see how well you can perform tasks with that half of your brain asleep.
A trained radiologist, neuropsychologist, and neurologist perform the Wada test in the angiography suite. There are two parts to the test. The first part is an angiogram, a test that evaluates blood vessels. Through an opening in the leg, a catheter is placed in the arteries that go to the brain. A small amount of dye is injected, and x-rays are taken. During the second part of the test, a small amount of anesthetic is given to one half on the brain. While one half of the brain is asleep, the other half is tested for memory and language. After a few minutes, the medicine wears off and the procedure is repeated on the other side. The reason the test is so important is because it helps to understand the exact location of a person's memory and language.