05.01.19
Today I read "Dyslexia and the Brain" from The International Dyslexia Association.
As a teacher it is helpful to understand brain-based differences (both in chemistry and function) of students with dyslexia. It is encouraging to know that, “some of the brain regions known to be involved in dyslexia are also altered by learning to read, as demonstrated by comparisons of adults who were illiterate but then learned to read” (p. 2). As teachers creating and facilitating effective language instruction, we strive to positively impact student brain development in the most literal sense.
Below are some highlights from the Orton-Gillingham article.
“Developmental dyslexia is associated with difficulty in processing orthography (the written form) and phonology (the sound structure)." (p.1)
“Data from [brain imaging] studies are typically collected on groups of people… not to diagnose individuals with dyslexia.” (p.1)
How are MRIs (Magnetic Resonance Images) useful for dyslexia research?
An MRI provides images that reveal info about brain anatomy, brain metabolites, and brain function.
What about Functional MRIs (fMRI)?
In a fMRI, an MRI signal bears indirect info about increases in blood flow from which researchers infer the location and amount of activity associated with a task… an fMRI does not require the use of radioactive tracers, making them safe for people of all ages and great for facilitating longitudinal studies.
Brain Area(s) used for Reading
No single region of the brain is used for reading. Instead, a network of regions in the left hemisphere work together.
Two skills associated with reading are especially interesting to researchers are:
Brain Function in Dyslexia
Researchers have found that people with dyslexia have altered left-hemisphere areas, including ventral occipito-temporal, temporo-parietal, and inferior frontal cortices (and their connections). Research has also show that dyslexia is universal across different world languages.
Genes & Brain Chemistry
“Differences in brain anatomy and brain function have been observed in people who carry dyslexia-associated genes, even those people who have good reading skills.” (p.2)
“This is a difficult aspect of research because differences in the brains of people with dyslexia are not necessarily the cause of their reading difficulties (for example, it could also be a consequence of reading less).” (p.2)
Cause vs. Consequence
“An important aspect of research on the brain and reading is to determine whether the findings are the cause or the consequence of dyslexia.”
Dyslexia and the Brain, The International Dyslexia Association. (2015). IDA Fact Sheet: http://www.ortonacademy.org/cms/uploads/dyslexia-and-the-brain-ida-fact-sheet2015.pdf