Increased diffusivity in superior temporal gyrus in patients with schizophrenia: a Diffusion Tensor Imaging study

Superior temporal gyrus (STG) volume reduction is one of the most consistent findings in schizophrenia. The goal of this study was to conduct the first Diffusion Tensor Imaging (DTI) study to investigate altered structural integrity in STG gray and white matter in patients with chronic schizophrenia compared with healthy controls.

Magnetic resonance imaging (MRI) and DTI were acquired in 21 male patients with schizophrenia and 22 age-, handedness-, and parental social economic status-matched male comparison subjects. After manual segmentation of gray and white matter, mean diffusivity and fractional anisotropy were measured within STG. Correlational analyses were also conducted to test possible associations between DTI and clinical measures, including positive and negative symptoms of schizophrenia.

Compared with controls, patients demonstrated reduced volume, bilaterally, in STG gray matter but not in white matter. For DTI measures, patients showed increased mean diffusivity, bilaterally, in STG gray matter, and in left STG white matter. In addition, mean diffusivity in left STG white matter showed statistically significant correlations with auditory hallucinations and attentional impairments in patients.

These findings suggest a disruption of tissue integrity in STG gray and white matter in schizophrenia. In addition, increased water diffusivity in left-side STG, which was associated with auditory hallucinations and attentional impairments, suggests the possibility of a disconnection among auditory/language processing regions in schizophrenia.