Auditory Cortex Characteristics in Schizophrenia: Associations With Auditory Hallucinations

Abstract

Background: Neuroimaging studies have demonstrated associations between smaller auditory cortex volume and auditory hallucinations (AH) in schizophrenia. Reduced cortical volume can result from a reduction of either cortical thickness or cortical surface area, which may reflect different neuropathology. We investigate for the first time how thickness and surface area of the auditory cortex relate to AH in a large sample of schizophrenia spectrum patients.

Methods: Schizophrenia spectrum (n = 194) patients underwent magnetic resonance imaging. Mean cortical thickness and surface area in auditory cortex regions (Heschl's gyrus [HG], planum temporale [PT], and superior temporal gyrus [STG]) were compared between patients with (AH+, n = 145) and without (AH-, n = 49) a lifetime history of AH and 279 healthy controls.

Results: AH+ patients showed significantly thinner cortex in the left HG compared to AH- patients (d = 0.43, P = .0096). There were no significant differences between AH+ and AH- patients in cortical thickness in the PT or STG, or in auditory cortex surface area in any of the regions investigated. Group differences in cortical thickness in the left HG was not affected by duration of illness or current antipsychotic medication.

Conclusions: AH in schizophrenia patients were related to thinner cortex, but not smaller surface area of the left HG, a region which includes the primary auditory cortex. The results support that structural abnormalities of the auditory cortex underlie AH in schizophrenia.

Keywords: Heschl’s gyrus; cortical surface area; cortical thickness; magnetic resonance imaging; neuroimaging; psychosis.

Fig. 1.

Cohen’s d (y-axis) for cortical thickness and surface area comparisons (covaried for age and sex) in regions of interest (x-axis) between schizophrenia patients with (AH+) and without (AH−) a history of auditory hallucinations. A positive Cohen’s d indicates AH+ > AH−.