Parietal Circuits and Conversion Seizures

SIR: We read with great interest the article by Devinsky et al.¹ on the role played by the nondominant hemisphere in conversion nonepileptic seizures. Our group² reported on nondominant parietal lobe dysfunction in hysterical behavior in this journal. We found that recent-onset conversive symptoms were accompanied by hypoperfusion of the nondominant frontoparietal regions as demonstrated by SPECT studies. We hypothesized that these findings reflected a dysfunction in the amygdala parietal lobe circuits based on explicit and affective implicit memories concerning traumatic events, which may result in changes in body image perception and behavior. Devinsky's findings give further credence to the hypothesis that the nondominant hemisphere modulates emotional memories to bodily manifestations.