Anomalous Cerebral Asymmetry in Patients with Schizophrenia Demonstrated by Voxel-Based Morphometry

Background: Evaluating cerebral asymmetry in schizophrenia patients potentially leads to understanding the extent to which the disorder involves a neurodevelopmental failure. We sought to clarify in which brain regions of the patient the normal cerebral asymmetry is disrupted and the extent of disruption. Methods: Voxel-based morphometry to evaluate gray matter asymmetry was carried out with magnetic resonance images from a total of 120 right-handed subjects. They comprised four groups of 30 subjects (i.e., male schizophrenia, female schizophrenia, male control, and female control). To examine gray matter asymmetry we generated images of the lateralization index. Results: The analysis within each of four groups revealed a consistent pattern of gray matter asymmetry over all groups. However group comparison between all patients and all healthy subjects showed significant difference in the cerebral lateralization in the pars triangularis and planum temporale. Frequency distributions of the lateralization index showed a skew toward rightward asymmetry in the pars trianglaris and a reduction in leftward asymmetry in the planum temporale in patients relative to control subjects. Conclusions: A disturbance of cerebral asymmetry in schizophrenia was suggested to be present in language-related regions, which might reflect a perturbation in the lateralization process underlying left cerebral dominance for language.