Left cerebral cortex complexity differences in sporadic healthy individuals with auditory verbal hallucinations: A...

Area of Science:

• Neuroscience
• Neuroimaging
• Brain Anatomy

Background:

• Auditory hallucinations (AVHs) are complex phenomena.
• Cerebral cortex complexity, measured by gyrification index and fractal dimensions, is a key neuroanatomical feature.
• Understanding brain surface differences in healthy individuals with and without AVHs can provide insights into neurobiological underpinnings.

Purpose of the Study:

• To characterize brain surface differences, specifically cerebral cortex complexity, between healthy individuals with and without auditory hallucinations (AVHs).
• To investigate potential correlations between these brain differences and the severity of AVHs.

Main Methods:

• A pilot study comparing 42 healthy individuals with AVHs (Hi-AVHs) and 50 healthy controls without AVHs.
• Utilized the Auditory Hallucinations Rating Scale (AHRS) to quantify AVH severity.
• Employed gyrification index and fractal dimensions to assess cerebral cortex complexity.

Main Results:

• Significant increases in gyrification index were observed in the left superior temporal gyrus, left temporoparietal junction, left superior frontal gyrus, and left parietal lobe in the Hi-AVHs group.
• Increased fractal dimensions were found in the left Wernicke's area, left Broca's area, and left parietal lobe.
• These cerebral cortex complexity differences were confined to the left hemisphere and did not correlate with AVH symptom severity.

Conclusions:

• Pilot findings suggest localized left-hemisphere brain surface complexity differences in healthy individuals with AVHs.
• The lack of correlation with AVH severity and absence of reverse changes in controls prevent postulating a direct relationship between cerebral cortex complexity alterations and AVHs.
• Further research is warranted to explore the neurobiological features associated with AVHs in healthy individuals.