HEMISPHERIC-SPECIALIZATION IN SCHIZOPHRENICS WITH PERCEPTUAL ABERRATION

Higher rates of left-handedness and atypical lateralization in schizop hrenics paired with findings of morphological abnormalities in cerebra l asymmetry suggest that the normal patterns of hemisphere specializat ion for processing verbal and spatial information may be anomalous in schizophrenics. The small number of studies that have addressed this q uestion have produced inconsistent findings and varied with subtype di agnosis, gender, type of task employed, task difficulty; and control o f handedness. Conflicting research findings also may be due to confoun ding from the heterogeneity of the schizophrenic construct and variabi lity in clinical symptoms across patients, The present study was desig ned to control for factors that may have confounded earlier studies. B ecause the study used perceptual measures, the relationship between sy mptoms of perceptual aberration and hemisphere advantages was examined using Chapman et al.'s (1978) Perceptual Aberration Scale (PAS). Fift een male schizophrenic patients and 14 male controls were administered tachistoscopic letter and facial recognition go/no-go reaction time t asks, Left hemisphere advantages were found for both controls and schi zophrenics on the letter task. Right hemisphere advantages were found for controls on the facial task but not schizophrenics. Instead, a str ong negative correlation was found between schizophrenics' PAS scores and hemisphere advantages (r = -0.685, p<0.007). Further analysis iden tified a subgroup of schizophrenics with perceptual aberration who exh ibited reversed left hemisphere advantages that increased as the PAS s cores increased. Additional research is needed to determine whether th is subgroup of schizophrenics constitutes a meaningful subtype with a distinct disease process that disrupts the development of normal cereb ral lateralization. The findings provide further evidence for the impo rtance of examining relationships between schizophrenics' performance on cognitive measures and their symptom patterns. (C) 1998 Elsevier Sc ience B.V. All rights reserved.