Brodmann area analysis of white matter anisotropy and age in schizophrenia

Diffusion tensor and structural MRI images were acquired on ninety-six patients with schizophrenia (69 men and 27 women) between the ages of 18 and 79 (mean=39.83, SD=15.16 DSM-IV diagnosis of schizophrenia according to the Comprehensive Assessment of Symptoms and History). The patients reported a mean age of onset of 23 years (range=13-38, SD=6). Patients were divided into an acute subgroup (duration ≤3 years, n=25), and a chronic subgroup (duration >3 years, n=64). Ninety-three mentally normal comparison subjects were recruited; 55 men and 38 women between the ages of 18 and 82 (mean=35.77, SD=18.12). The MRI images were segmented by Brodmann area, and the fractional anisotropy (FA) for the white matter within each Brodmann area was calculated. The FA in white matter was decreased in patients with schizophrenia broadly across the entire brain, but to a greater extent in white matter underneath frontal, temporal and cingulate cortical areas. Both normals and patients with schizophrenia showed a decrease in anisotropy with age but patients with schizophrenia showed a significantly greater rate of decrease in FA in Brodmann area 10 bilaterally, 11 in the left hemisphere and 34 in the right hemisphere. When the effect of age was removed, patients ill more than three years showed lower anisotropy in frontal motor and cingulate white matter in comparison to acute patients ill three years or less, consistent with an ongoing progression of the illness.