Abstract
Background: There have been many attempts at explaining the underlying neuropathological mechanisms of auditory verbal hallucinations (AVH) in schizophrenia on the basis of regional brain changes, with the most consistent findings being that AVH are associated with functional and structural impairments in auditory and speech-related regions. However, the human brain is a complex network and the global topological alterations specific to AVH in schizophrenia remain unclear.Methods: Thirty-five schizophrenia patients with AVH, 41 patients without AVH, and 50 healthy controls underwent resting-state functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI). The whole-brain functional and structural networks were constructed and analyzed using graph theoretical approaches. Inter-group differences in global network metrics (including small-world properties and network efficiency) were investigated.Results: We found that three groups had a typical small-world topology in both functional and structural networks. More importantly, schizophrenia patients with and without AVH exhibited common disruptions of functional networks, characterized by decreased clustering coefficient, global efficiency and local efficiency, and increased characteristic path length; structural networks of only schizophrenia patients with AVH showed increased characteristic path length compared with those of healthy controls.Conclusion: Our findings suggest that less “small-worldization” and lower network efficiency of functional networks may be an independent trait characteristic of schizophrenia, and regularization of structural networks may be the underlying pathological process engaged in schizophrenic AVH symptom expression.
Highlights
Hallucinations, which are defined as any perceptual experience in the absence of corresponding stimuli in the external world (David, 2004), are one of the most debilitating symptoms of schizophrenia
There were no significant differences in antipsychotic dosages, durations of illness, Positive and Negative Syndrome Scale (PANSS) negative score, PANSS general score and PANSS total score between auditory verbal hallucinations (AVH) and nAVH groups
We found that (1) schizophrenia patients with and without AVH exhibited common disruptions of functional networks, characterized by decreased clustering coefficient, global efficiency and local efficiency, and increased characteristic path length; (2) structural networks of only schizophrenia patients with AVH showed increased characteristic path length compared with those of healthy controls
Summary
Hallucinations, which are defined as any perceptual experience in the absence of corresponding stimuli in the external world (David, 2004), are one of the most debilitating symptoms of schizophrenia They may involve any of the senses, auditory verbal hallucinations (AVH) or “hearing voices” are the most prevalent type of hallucinations in schizophrenia (Andreasen and Flaum, 1991), and affect about 60–80% of schizophrenic patients. Some key brain regions involving auditory processing, speech generation and speech perception have been identified These AVH-related brain regions include the superior temporal gyrus, Wernicke’s area, Broca’s area, and arcuate fasciculus bundle. There have been many attempts at explaining the underlying neuropathological mechanisms of auditory verbal hallucinations (AVH) in schizophrenia on the basis of regional brain changes, with the most consistent findings being that AVH are associated with functional and structural impairments in auditory and speech-related regions. Conclusion: Our findings suggest that less “small-worldization” and lower network efficiency of functional networks may be an independent trait characteristic of schizophrenia, and regularization of structural networks may be the underlying pathological process engaged in schizophrenic AVH symptom expression
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
