Wada test

n. A test for determining the separate functioning of the two cerebral hemispheres in which a drug, usually sodium amytal, is injected into one of the internal carotid arteries, which take blood to one side of the cerebrum, and then testing the person's abilities with the functions of one side of the cerebrum depressed. This test is primarily used before brain surgery, typically temporal leucotomy for intractable epilepsy.