P2-28. Single-event-related changes in Oxy-Hb during verbal discrimination tasks in schizophrenic patients: Correlation with the symptom

Abstract

Schizophrenic patients have been associated with cognitive dysfunction including attention and executive functions. “Shiritori” is a very popular word chain game in Japan. This game requires players to generate a word that begins with the last syllable of the preceding word. The present study assessed the difference of hemodynamic changes between schizophrenic patients and healthy controls during a Japanese word production task (shiritori) based on a single-event-related design measured by a multi-channel NIRS system. Relationships between brain activation and clinical symptoms were also examined. The subjects were 30 schizophrenic patients and 30 age- and sex-matched healthy native-Japanese speakers. Two contrasting single events (reading task as non-target stimuli, and Shiritori task as target stimuli) were randomly performed at least 20 times each. Data were calculated as a discrimination task from each averaged waveform. The patients showed significantly less activation of the prefrontal cortex than healthy subjects. In addition, there was a significant correlation between the activation value and negative symptom score as well as general psychopathological score in patients in the left front-polar region. These findings suggest that a single-event-related NIRS measurement using verbal discrimination tasks is a useful psycho-physiological index reflecting the cognitive function of schizophrenic patients.