Magnetic resonance imaging of the corpus callosum in developmental dyslexia

The cerebral anatomy of reading processing in normals and developmental dyslexics is incompletely understood. However, the core problem of developmental dyslexia seems to be located in the word recognition aspect of reading. Most probably, normal reading involves right-hemisphere cerebral functions in addition to the more important left-hemisphere functions. The major communicator between the hemispheres is the corpus callosum and the splenium of the corpus callosum, in particular, may be involved in efficient word processing. In this study we could not find any gross differences in size of the total corpus callosum or the splenium between groups of dyslexics and controls. Furthermore, we could not find any abnormalities in size of the corpus callosum in subgroups of dyslexia related to gender, linguistic deficiencies, or symmetry/asymmetry of the planum temporale.