Hemispheric asymmetry of the white matter microstructure in schizophrenia patients with persistent auditory verbal hallucinations

The link between hemispheric asymmetry and auditory verbal hallucinations in schizophrenia is underexplored with neuroimaging evidence. This study examined white matter asymmetries in schizophrenia patients. Diffusion tensor imaging data from 52 patients with persistent auditory verbal hallucinations, 33 who never experienced auditory verbal hallucinations, and 40 healthy controls were analyzed. Asymmetry indices for fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity were calculated for the whole-brain white matter skeleton and 22 pairs of regions of interest. The persistent auditory verbal hallucination group showed reduced fractional anisotropy asymmetry index in the whole-brain white matter skeleton compared to healthy control and never experienced auditory verbal hallucination groups, indicating altered asymmetry. Region of interest analysis revealed decreased fractional anisotropy asymmetry index in nine pairs and increased mean diffusivity AI in two pairs in the persistent auditory verbal hallucination group. Greater rightward asymmetry in the superior longitudinal fasciculus correlated with more severe auditory verbal hallucinations in persistent auditory verbal hallucination patients. No significant asymmetry differences were found between never experienced auditory verbal hallucinations and healthy control groups. Ridge regression analysis demonstrated that including the fractional anisotropy asymmetry index of the superior longitudinal fasciculus increased the explained variance in auditory verbal hallucination severity. These findings highlight distinct white matter asymmetry patterns in persistent auditory verbal hallucination patients, suggesting that hemispheric asymmetry plays a key role in the pathology of auditory verbal hallucinations in schizophrenia.