Juhn A. Wada and the sodium amytal test in the first (and last?) 50 years.

Fifty years ago Juhn A. Wada developed the intracarotid amobarbital procedure (IAP), a test in which first one and then the other cerebral hemisphere is temporarily anaesthetised through direct intracarotid application of sodium amytal. The IAP was devised initially as a method to allow unilateral electroconvulsive shock therapy for psychosis. The method subsequently proved its value for the lateralisation of language and, following adaption of the test protocol, for the assessment of memory functions. Thus the IAP became the standard test in the presurgical evaluation for resective surgical treatment of medically intractable epilepsy. This paper will briefly review the history of the IAP, the controversies concerning its current applications and its expected eventual replacement by less invasive and more easily repeatable methods, notably functional magnetic resonance imaging.