The Corpus Callosum is a large structure in the brain that connects the two hemispheres. Its roll is to pass information from the left hemisphere to the right and vice versa. This is a vital as the two hemispheres perform different tasks and need to communicate efficiently. The Corpus Callosum has been linked by scientists to dyslexia and ADHD for a long time. They theorize that the problems in these conditions may be caused by insufficient information passing between the two halves of the brain.
Plenty of research has been done on the size of the Corpus Callosum in dyslexics and in children with ADHD and the results have generally found a correlation. Its seems that the anterior region of the Corpus Callosum was significantly smaller in the dyslexic children. However the results are not clear cut with at least one study has found no difference in dyslexic versus non-dyslexic children and another study on adult, male dyslexics found areas of the Corpus Callosum were larger that normal.
These variation in results may have several causes. How the study defines dyslexia when selecting there sample population may make an impact. The sophistication of the equipment used is important. Some of these studies date back to the early 1990’s when fMRI technology was still new so the ability to accurately measure the Corpus Callosum may of been poorer. Our knowledge of the brains structure has also improved and later studies have tended to focus on specific areas of the Corpus Callosum, partially areas linked to the processing of sounds. However, with a lot of maybes and provisos it does look like the Corpus Callosum in dyslexic and ADHD children is subtly different.
Being able to efficiently pass information from one half of the brain to the other is vital. Much like a road between to busy cities. The better the road, the more information, wealth and trade will flow between the cities. So in dyslexic and ADHD children this road may be poor and restricting vital traffic. But there is hope that this roadway can be improved.
Its has been found that the Corpus Callosum was larger in professional musicians than in non-musicians. Playing instruments involves a lot of cross hemisphere processing to keep both hand’s movements in time with each other. This suggest that by regular practice the Corpus Callosum can be strengthen. The Dore Program, Interactive Metronome and primitive reflex based treatments such as INPP all involve cross-lateral movements designed to train this area of the brain. Other activities may also help. Such as computer games like Wii Drums and some aspects of Wii Fit may also help.
If you would like to try out your Corpus Callosum, have a look at this test on Mind Hacks. You will need a friend to help you but otherwise it is an extremely simple demonstration of what the Corpus Callosum does.
Dyslexia and corpus callosum morphology
Magnetic resonance imaging of the corpus callosum in developmental dyslexia
Corpus callosum morphology, as measured with MRI, in dyslexic men
Developmental Dyslexia: Re-Evaluation of the Corpus callosum in Male Adults
Less developed corpus callosum in dyslexic subjects—a structural MRI study
Increased corpus callosum size in musicians