Lateralized lexical decision in schizophrenia: hemispheric specialization and interhemispheric lexicality priming

Reports of left-hemisphere dysfunction and abnormal interhemispheric transfer in schizophrenia are mixed. The authors used a unified paradigm, the lateralized lexical decision task, to assess hemispheric specialization in word recognition, hemispheric error monitoring, and interhemispheric transfer in male, right-handed participants with schizophrenia (n 34) compared with controls (n 20). Overall, performance and error monitoring were worse in patients. However, patients like controls showed left-hemisphere superiority for lexical processing and right-hemisphere superiority for error monitoring. Only patients showed selective-interhemispheric lexicality priming for accuracy, in which performance improved when the lexical status of target and distractor stimuli presented to each hemifield was congruent. Results suggest that schizophrenia is associated with impaired monitoring and with increased interhemispheric automatic information transfer rather than with changed hemispheric specialization for language or error monitoring. To assess the presence of disturbed functional lateralization and altered callosal connectivity in schizophrenia, we used a lateralized lexical decision paradigm that has been well validated in controls and split-brain participants (Iacoboni, Rayman, & Zaidel, 1997