Attentional resources and hemispheric functional asymmetry in schizophrenia

Inconsistent findings within certain areas of schizophrenia research--processing of verbal and pictorial stimuli, and hemispheric functional asymmetry--suggest the importance of examining the attentional resources associated with the cerebral hemispheres among schizophrenics. A cognitive task battery was developed which assessed the functioning of the left and right hemispheres under varying attentional loads. This battery was administered to paranoid and non-paranoid schizophrenics, and three control groups. Error rate and response latencies were monitored. It was found that the schizophrenics, particularly the non-paranoids, displayed evidence of a generalized decrease in available resources across attentional pools. In addition, response latencies were indicative of a complex interaction involving loads and visual field of stimulus presentation, which differed across schizophrenic subtypes. These lateralized effects among the schizophrenics did not interact with the differential sensitivity of the hemispheres to stimulus characteristics.