Brain Function of Reading, Writing and Spelling Learning Disabilities

All lobes of the brain are important for reading, writing and spelling. The Frontal Lobe deals with controlling speech, planning. Also in this lobe is Broca's area. Broca's area deals with organization, production and the manipulation of language and speech. The Parietal Lobe links spoken and written language to memory in order for meaning to be attached. The Temporal Lobe deals with verbal memory. Wernicke's area is in this lobe and is important for language understanding. Lastly, the Occipital Lobe deals with identification of visual information such as letters.

Research has been done to suggest that two more areas/systems of the brain are involved in reading. They are the  left parietotemporal system and the left occipitotemporal area. The left parietotemporal system is used for effortful decoding and word analysis. While, the left occipitotemporal area is used for rapid access of words. These areas are important for understanding spoken and written language as well as being able to read fluently and effectively.

Brain Differences in People With and Without Dyslexia

A study done by Booth and Burman found that people with dyslexia have less gray matter in their parietotemporal lobe than people without dyslexia. Since gray matter aids in processing information this can cause a problem in precessing speed and the ability to process important information. They also found that there was less white matter in this area as well. White matter corresponds with reading skill, less white matter can cause deficiencies in the abilities to communicate with other parts of the brain for reading. A different study by Heim and Keil showed that people with dyslexia have a more symetrical brain structure while people without dyslexia have an asymmetrical brain structure. For example, people without dyslexia their left side or hemisphere of the brain is larger than the right. People with dyslexia their brain hemispheres are the same on each side or the right is slightly bigger.

Brain Functions of People With and Without Dyslexia

Several studies looked at brain activation in people with and without dyslexia in a fMRI. The fMRI looks at brain activity. They examined children that were right-handed with and without a reading disability. These children had to identify names of letters or sounds, saying nonsnese words and comparing meanings of real words. The study found that children without a reading disability had more acitivation in all areas that deal with reading. they also had more acitivty in the left hemisphere than  children with a reading disability.                                     http://hollergen677s09.weebly.com/

 Children with reading disabilities had less activity in the posterior part of their brains in the areas that are important for reading but had more acitivity in the lower frontal portions of their brain. Researchers think this is  to make up for the lack of activity in the posterior parts of the brain.

Resources:

http://www.asha.org/Publications/leader/2007/070904/070904f.htm

http://www.ldonline.org/article/14907/

http://www.haskins.yale.edu/papers/intervention_biol_psych_200.pdf