Sowell et al. reported an average volume reduction of 12% in subjects with PEA, as compared to control subjects144. Using voxel-based morphometric analyses, Sowell et al. demonstrated greater volume reductions in the posterior temporal and parietal lobes in FASD group142. In a subsequent volumetric study, these findings were consistently replicated143. Using whole brain surface analyses, regional shape differences in an FASD group were studied and compared with matched controls. This method measures the distances from the center (DFC) or distances from a particular point on the anterior commissure to specific landmark points in different brain regions. In the PEA group, the DFC on both sides of the inferior parietal regions were less than those of the control group, causing these regions to look “narrow”. Also, the DFC to landmarks on the cortical surface of the left orbito-frontal cortex were shorter in FASD subjects, creating a “blunted” effect in the frontal lobe. Sowell et al. also observed structural irregularities corresponding to either an increase in gray matter density, and/or in WM volume reductions. Density maps within both the parietal lobes, especially the left hemispheric, showed reduction in lobar volumes, with increased gray matter and decreased WM densities.
