Cortical responsiveness during inner speech in schizophrenia: An event-related potential study

Objective: The study assessed the effects of inner speech on auditory corti cal responsiveness in schizophrenia. Method: Comparison subjects (N=15) and patients with schizophrenia (N=15) w ere presented with acoustic and visual stimuli during three conditions: whi le subjects were silent, when spontaneous inner speech might occur; during directed inner speech, while subjects repeated a statement silently to them selves; and while subjects listened to recorded speech. N1 event-related po tentials were recorded during the three conditions. Results: N1 event-related potentials elicited by acoustic stimuli, but not by visual stimuli, were lower during directed inner speech than during the silent baseline condition in the comparison subjects but not in the patient s. Conclusions: Abnormal auditory cortical responsiveness to inner speech in p atients with schizophrenia may be a sign of corollary discharge dysfunction , which may potentially cause misattribution of inner speech to external vo ices.