Epilepsy Program

Wada Test

The Wada (intracarotid amobarbital) test is done to localize speech and memory functions in some candidates for epilepsy surgery. The internal carotid vascular distribution of half of the brain is put to sleep through injection of a quick-acting barbiturate into the internal carotid artery (via a catheter placed in the femoral vein at the groin). 

During the next 5-15 minutes, speech and memory are tested. Surgery can be performed on the temporal lobe of the speech-dominant side, but not as much brain can safely be removed as on the non-dominant side. Global amnesia after injecting one internal carotid artery is a danger signal for surgery, because this result suggests that there may be severe memory problems after the operation. Not every surgical candidate requires a Wada test.


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