Dichotic listening asymmetries and psychotic symptoms in schizophrenia: a preliminary report.

Schizophrenic subjects were compared with both psychiatric control and normal control groups on two verbal measures of functional hemispheric asymmetry on a dichotic listening task. One measure of language perception showed little variation in ear differences across groups. However, the task that contained both attentional and language-processing components showed variations in asymmetry according to symptomatology. Subjects with high scores on scales of hallucinations and delusions showed a pattern of ear differences that was not found in those with low scores on these symptom dimensions. The results may reflect cognitive factors in a dysfunctional information-processing system and, in particular, attentional disturbance rather than anomalies in the lateralization of language.