Learning Disabilities

Differences in brain anatomy have been consistently found in the area where sound-symbol relationships are believed to take place. Neuroimaging has now allowed further evaluation of the brain in living children. Studies found differences in the area of the brain responsible for sound-symbol interpretation (Hynd et al. 1990) as well as in the left hemisphere and frontal areas of the brain believed to be responsible for speaking ( Jernigan et al. 1991; Semrud-Clikeman et al. 1991). Neurons were found to be out of place, additional neurons in places where they should not be were found, and smaller volumes of the planatemporale were found. This area is responsible for auditory processing (Hynd and Semrud-Clikeman 1989). Such regional differences imply a neurodevelopmental process that went awry during gestation rather than brain damage or environmental influences. It is important to note that this asymmetry/symmetry may not be solely responsible for learning disabilities, although it is likely a major contributor to such difficulties (Morgan and Hynd 1998; Steinmetz and Galaburda 1991).