Auditory P300 topography and neuropsychological test performance: evidence for left hemispheric dysfunction in schizophrenia.

Asymmetrical topography of the auditory P300 with reduced left hemispheric amplitudes and, consequently, a right-lateralized peak of the P300 electrical field has been repeatedly reported in schizophrenia. This was interpreted as an indication of reduced left-hemispheric activity during the simple cognitive P300 task. Since generator locations calculated from the surface potentials are ambiguous, further evidence is required to support this conclusion. In the present study, 13 stabilized DSM-III-R schizophrenic patients were studied with an auditory P300 paradigm and neuropsychological methods sensitive to functional brain asymmetries. The tests included the verbal paired associates test (Goldstein et al 1988, Cortex 24:41-52) and the nonspatial conditional associative learning test (Petrides 1985, Neuropsychologia 23:601-614). A significant correlation was found between right-sided lateralization of the P300 maximal positivity and neuropsychological evidence for left hemispheric temporal- hippocampal dysfunction. Attentional performance was correlated with P300 amplitudes. The results of this study provide further evidence that right-sided lateralization of the P300 peaks results from dysfunction of left-hemispheric neuronal generators.