Aetiological factors in dyslexia: IV. Cerebral hemispheres are functionally equivalent.

Left parieto-occipital EEG leads record a frequency spectrum in dyslexics which is consistently different from normals, indicating differences in the functional organization of these areas. EEG coherence values indicate normals to have greater sharing between hemispheres at symmetrical locations. Dyslexics demonstrate greater sharing within hemisphere. A parallel study indicated that CT scans of dyslexics parieto-occipital regions demonstrates reversal or lack of cerebral asymmetry.