Auditory verbal hallucinations and the interhemispheric auditory pathway in chronic schizophrenia

Abstract

Objectives. The interhemispheric auditory pathway has been shown to play a crucial role in the processing of acoustic stimuli, and alterations of structural and functional connectivity between bilateral auditory areas are likely relevant to the pathogenesis of auditory verbal hallucinations (AVHs). The aim of this study was to examine this pathway in patients with chronic schizophrenia regarding their lifetime history of AVHs. Methods. DTI scans were acquired from 33 healthy controls (HC), 24 schizophrenia patients with a history of AVHs (LT-AVH) and nine schizophrenia patients without any lifetime hallucinations (N-LT-AVH). The interhemispheric auditory fibre bundles were extracted using streamline tractography. Subsequently, diffusivity indices, namely Fractional Anisotropy (FA), Trace, Mode, Axial and Radial diffusivity, were calculated. Results. FA was decreased over the entire pathway in LT-AVH compared with N-LT-AVH. Moreover, LT-AVH displayed decreased FA and Mode as well as increased radial diffusivity in the midsagittal section of the fibre tract. Conclusions. These findings indicate complex microstructural changes in the interhemispheric auditory pathway of schizophrenia patients with a history of AVHs. Alterations appear to be absent in patients who have never hallucinated.

Key words::

• schizophrenia
• brain imaging
• MRI
• diffusion tensor imaging
• auditory verbal hallucinations

Acknowledgements

We thank all subjects for their participation in the study. This work is part of Marlene Wigand's doctorate thesis (Dr. med.). This work was supported, in part, by grants from the Deutsche Forschungsgemeinschaft (DFG SFB 936 to CM, GL); National Institutes of Health (P50 MH 080272 to MES; R01 MH082918 to SB); Veterans Affairs Merit Award to MES; Veterans Affairs Schizophrenia Center Grant to MES; NARSAD Distinguished Investigator Award to MES. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Statement of Interest

None to declare.