Neuroscience of Reading Disabilities in Children
Section Editor: | Professor, Scientific Director, Department of Biomedical Engineering University of Alberta Canada |
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Key Messages
What do we know?
Within the brain, there are several regions that are related to the ability to read. Researchers have used magnetic resonance imaging (MRI) technology to visualize these areas. MRI technology has been identified as a beneficial tool for research because it is:
1. safe;
2. straightforward for use with children (children are only required to lie still for a minimal amount of time); and
3. effective for identifying brain structure differences.
The brain is made up of a network of connected “wires” and “computers” that serve different functions. Complex cognitive tasks, such as reading, often require the participation and coordination of multiple systems. MRI technology has been used to identify where problems are potentially located within these systems. For children with reading disabilities, some differences in brain structure and specific brain regions have been identified.
New research comparing children with dyslexia and typically developing readers has indicated that there is substantially more brain activity in specific brain regions for typically developing readers. In order to compensate for the lack of regional brain activity, readers with dyslexia have learned to make use of an alternate brain system, which primarily uses memory to function. Specific intervention, targeted at increasing and improving brain activity in the deficient areas, demonstrated improved brain activation patterns in all areas contributing to reading. This improvement fostered activity patterns similar to those of typically reading children.
Reading disabilities are sometimes referred to as developmental dyslexia. There is a known genetic component to reading disabilities, meaning that they run in families. The specific genes that contribute to reading disabilities have yet to have been identified, although several have been identified as potential contributors. Common genetic factors are known to contribute both to reading disabilities and to attention deficit/hyperactivity disorder (ADHD).
One theory about the cause of reading disabilities involves the development of specific brain regions during pregnancy. Because of differences in regional brain development, the organization of cells within the brain becomes disrupted. Brain studies involving reading disabilities demonstrate two types of cell organization abnormalities, known as ectopias and dysplasias, in which certain types of cells develop in the wrong locations in the brain. Brain cell organization abnormalities may help us to better understand reading disabilities as they occur early on in development.
What can be done?
Parents and Educators
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Because reading-related brain activity patterns in children with dyslexia are different than those of typically reading children, these students require additional time on tests and evaluations.
Policymakers
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Some clarification regarding the relationship between brain structure and reading ability would be beneficial. The cause and effect remain unclear. Longitudinal studies involving children who have not yet learned to read would be ideal.
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Studies in brain structure before, during and after reading intervention would be useful to identify (and later, understand) any brain changes.
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Because so few studies have been completed, males and females have been combined as a group. Differences in brain structure between males and females as they relate to reading would be useful.
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The early stages of brain activation intervention have demonstrated strong potential avenues for treatment. Further study of this type of intervention will be important for effective treatment for children with dyslexia.
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Once the specific genes contributing to reading disabilities have been identified, functional intervention targeting reading disabilities can be further explored.
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It is extremely difficult to separate the influences of genetics and environmental factors on reading disabilities. The study of the interrelationship of these factors will be beneficial to further understand and develop intervention strategies.
