In the surgical treatment of focal epilepsy, the presence of speech representation has often been verified by electrical stimulation of the speech zones in the frontal and parietal opercula with the cortex exposed under local anesthesia. 4–7 Interruption of counting or naming produced by such stimulation gives positive evidence in this regard. Lack of such response, however, is not certain proof that speech is in the other hemisphere, since in some instances the electrical stimulating current does not seem to be an adequate stimulus and no effect is observed, even though speech is actually subserved by the convolutions being stimulated. In view of the obvious importance of accurate knowledge of the lateralization of speech dominance when operating near the Sylvian regions in ambidextrous and left-handed individuals, further studies regarding the technique of intracarotid injection of Sodium Amytal seemed indicated, particularly with regard to the margin of safety in relation to dose and to the effect of accidental injection into the vertebral artery. This report concerns some experimental studies on the monkey bearing on these points, and a brief clinical report on the use of this test in a consecutive series of 20 patients.
WadaJ. lsqb;A new method for the determination of the side of cerebral speech dominance. A preliminary report on the intracarotid injection of Sodium Amytal in man.] Igaku to Seibutsugaku [Medicine and Biology]194914: 221–222. (Japanese)WadaIgaku to Seibutsugaku14: 221–222. (Japanese)
WadaJ.KirikaeT. [Neurological contribution to induced unilateral paralysis of human cerebral hemisphere. Special emphasis on experimentally induced aphasia.] Hokkaido Igaku Zasshi [Acta med. Hokkaido]194924: 1–10. (Japanese)WadaKirikaeHokkaido Igaku Zasshi24: 1–10. (Japanese)