Further study of hemispheric asymmetry patterns using cortical matching techniques applied to the PEA group showed significantly reduced “right to left” gray matter ratios in posterior temporal lobes of subjects with PEA compared to controls. Increase in gray matter density was observed in the inferior parietal and superior temporal lobes, while WM hypoplasia was most prominent in the perisylvian and inferior parietal regions. An inverse relationship of regional volume with gray matter density was observed 145. The authors suggest that neurocognitive deficits in language processing, and object and face recognition frequently found among subjects with PEA can be explained by parietal lobe involvement. Additionally, the frontal and parietal lobe abnormalities may explain impairments in executive functions, spatial memory and reduced response inhibition often seen in individuals with PEA 146.
