Impaired suppression of processing in schizophrenic patients suggested by ERPs obtained in a selective attention task

In the present study. we focused on the ability of suppression of processin g in schizophrenic patients, using event-related potentials (ERPs) recorded during a selective attention task. During the task, subjects were required to focus on one ear, counting deviant stimuli, those deviating in duration from a sequence of standard stimuli. We compared amplitude data of two pos itive components differing in latency elicited by standard stimuli, which r eflect suppression of stimulus processing, between schizophrenic patients a nd normal controls. Significant between-group differences were obtained spe cifically in the right ear attended condition, suggesting impaired suppress ion of processing in schizophrenics mediated in the left hemisphere. (C) 20 01 Elsevier Science B.V. All rights reserved.