Unnatural practices, unspeakable actions: a study of delayed auditory feedback in schizophrenia

OBJECTIVE: It has been suggested that auditory hallucinations and delusions of control in persons with schizophrenia could involve a disconnection between an "intention center" and a "monitoring center." METHOD: To test this model directly, the authors used a delayed auditory feedback paradigm in which the subject hears his or her own speech delayed electronically by a fraction of a second. In normal, subjects this produces dysfluency, which is thought to occur because an expectancy about the perceptual arrival of speech, formed in a monitoring center on the basis of corollary discharge from an intention center, is violated. If, however, a disconnection were present in schizophrenia, such an expectancy would not be formed; hence, less dysfluency should occur. Fifteen patients with chronic schizophrenia (10 of whom experienced auditory hallucinations and/or delusions of control) and 19 normal subjects were studied. RESULTS: Rather than exhibiting less dysfluency than the normal subjects, patients with delusions and/or hallucinations exhibited significantly more dysfluency. CONCLUSIONS: These results do not support a cognitive model of disconnection.