A controlled study of temporal lobe structure volumes and P300 responses in schizophrenic patients with persistent auditory hallucinations

Recent studies of cerebral pathology in patients with schizophrenia have fo cused on symptomatological and electrophysiological correlates of reduced t emporal lobe structure volumes. Volume deficits of the left superior tempor al gyrus have been correlated with auditory hallucinations as well as to le ft-sided P300 amplitude reduction. However, caution is needed to interpret correlational data as evidence of a specific relationship. Therefore, a con trolled study was undertaken on schizophrenic patients with and without aud itory hallucinations. MRI-defined volumes of the left superior temporal gyrus and other temporal lobe structures were quantified from 3-mm coronal slices in 15 schizophreni c patients with chronic auditory hallucinations (hallucinators), 15 schizop hrenic patients without auditory hallucinations (nonhallucinators) and 17 h ealthy controls. In all subjects a simple oddball paradigm was used to elic it P300 responses at temporal and centro-parietal electrode sites. No evidence was found for volume reductions of temporal lobe structures in the combined patient group compared with controls, or in the hallucinators compared with the nonhallucinators. The patients did show left P300 amplitu de reduction compared with controls, particularly in the hallucinator group . Correlations between volumes of left temporal lobe structures and left P3 00 amplitudes were low and not significant. The results of the present study do not indicate that auditory hallucinatio ns and associated abnormal electrophysiological activity are the consequenc e of atrophy of localized temporal lobe structures. However, replication in a larger sample of subjects is needed before firm conclusions can be drawn . (C) 1999 Elsevier Science B.V. All rights reserved.