Laterality, Attention and Rate Effects in the Auditory Temporal Discrimination of Chronic Schizophrenics: The Effect of Treatment with Chlorpromazine

Abstract

Schizophrenic patients, non-psychotic patients and healthy subjects were required to detect longer target tones from a sequence of short tones presented to either ear. The rate of stimulus presentation and the frequency of switches between the ears were varied. The schizophrenic patients were examined for four weeks while on standard clinical doses of chlorpromazine, for four weeks while on placebo, and for four weeks following reinstatement of medication. Lateral asymmetries in the performance of the schizophrenics were found to diminish in proportion to both the duration and the dosage of medication. The results are consistent with the hypothesis that chlorpromazine causes an improvement of left hemisphere performance relative to the right. The performance of the schizophrenics, relative to that of comparison subjects, deteriorated as the rate of stimulus presentation increased, supporting the hypothesis that schizophrenics have particular difficulties in response selection or organization.