Severe negative emotional reactions in intracarotid sodium amytal procedures: further evidence for hemispheric asymmetries?

Intracarotid sodium amytal (ISA) procedures are commonly used to determine the lateralization of language and memory functions in presurgical evaluation of epileptic patients. Besides, they provide a means for studying putative hemispheric asymmetries in the organization of emotional behavior. In this study, we report the incidence of negative emotional reactions in eighty epileptic patients undergoing ISA procedures as a part of presurgical evaluation. There were only four such reactions in a total of 159 tests (2.5%), all in right-handed patients with left cerebral dominance for language functions. In one case, emotional outbursts occurred with barbiturization of the nondominant hemisphere. This observation invalidates the hypothesis that a loss of left-hemispheric functions generally leads to negative emotional reactions due to a right hemisphere specialization for the processing of negative emotions. Rather than pointing to fixed hemispheric asymmetries, our findings suggest that severe negative emotional reactions result from a flexible cognitive evaluation of the organism's overall situation.