Decision-making in temporal lobe epilepsy examined with the Iowa gambling task

Although memory, language, and executive functions have been extensively studied in patients with mesial temporal lobe epilepsy (MTLE), few investigations of the decision-making abilities of these patients have been performed. We studied implicit decision-making (decisions under ambiguity) in right and left MTLE patients using the Iowa Gambling Task. The Iowa Gambling Task is believed to detect deficits in decision-making caused by either ventromedial prefrontal cortex or amygdalo-hippocampal lesions. In the present study, MTLE patients scored poorly compared to healthy controls on this task, and right MTLE patients exhibited worse performance than left MTLE patients. Our findings indicate that the amygdalo-hippocampal complexes play important roles in decision-making. The right amygdalo-hippocampal complexes may play more important roles in implicit decision-making in particular.