Brain Imaging and Learning Disabilities

Emerging findings suggest that children with learning disabilities process information differently from those without learning problems. Differences in developmental have shown that fluent adult readers utilize the frontal regions more than children who are beginning to read (Schlaggar, 2003). The left frontal region becomes more active over development with more fluent child readers activating this area more than children with difficulties (Schlaggar et al., 2002). Moreover, children with learning problems show a differential pattern from normal readers activating the parietal and occipital areas more than the frontal regions as well as more activation in the right hemisphere than in the left. This finding is important because activation of the left hemisphere, a region specialized for language functions, plays an important function in reading. The change from posterior systems in early reading (visual- perceptual processes) to frontal systems by more fluent readers suggest that the progression from simple letter and word calling to comprehension requires a maturation of neural pathways from the back of the brain to the front (Shaywitz, 2003). Moreover, children show a more diffuse activation when beginning to learn to read that gradually becomes more specialized as the reading process improves.

Similarly, when asked to read single words normal readers showed left hemispheric activation while those with dyslexia showed more right hemispheric activation (Breier, et al., 2003; Papincolaou, 2003). Changes from right hemispheric processing to left hemispheric processing have been found to occur with improvement in reading skills. These changes are also found when improvement in language functioning occurs. Such changes are not found for children with dyslexia as the reading process does not become automatic and effortless.

Gabrieli (2003) found that the region most responsible for auditory processing and language is more activated in good readers compared to those who had compensated for their dyslexia. The more activated the white matter tracts are that carry the signals throughout the brain, the better the scores on reading measures. These studies also found that improvements were found in activation following remediation of auditory processing ability. It is not clear, presently, whether these changes continue over time with further study needed to understand possible brain response to remediation.

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