Cerebral Laterality and Consciousness

Ahern et al,¹ in their otherwise interesting article on multiple personality and temporolimbic epilepsy, described a patient (patient 2) who, following left (dominant)-hemisphere inactivation, in addition to developing right hemiparesis, became "obtunded" and remained so for approximately 7 to 8 minutes. The authors proceeded, then, to say that this "was probably due to cross-fill of amobarbital into the contralateral anterior cerebral arterial territory, which resulted in bilateral frontal deactivation." Granted, transient delta slowing in the electroencephalogram was seen in the right frontal region, in addition to the areas supplied by the left anterior and middle cerebral arteries; but, considering that such electroencephalographic findings are not incompatible with unilateral test results, could not another explanation of the "obtundity" observed be found in the reported role of the dominant hemisphere for speech in matters of consciousness (Terzian², Serafetinides et al,³ and Hommes and Panhuysen⁴). Indeed, a careful and