Reading aloud is an important piece of diagnosing dyslexia for both children and adults. Most dyslexia evaluations involve reading aloud so that clinicians can evaluate how well an individual responds to unfamiliar words. Researcher William W. Graves, associate professor of psychology at Rutgers University, asked whether a reader’s approach to decoding unfamiliar words could affect his or her proficiency at reading aloud. A reader can guess at a word’s pronunciation based on its meaning or spelling. These different approaches to reading have a biological basis in the brain that could affect how dyslexia is diagnosed.
Graves and his team began by searching for evidence of meaning-based versus sound-based reading styles. They started by evaluating 18 college-educated proficient readers. The researchers observed the readers’ brain activity using functional magnetic resonance imaging (fMRI) while the volunteers read word lists that included “imageable” words—words that people easily picture.
In the next experiment, the researchers tested whether the brain responded differently to words that imageable words compared to non-imageable words. During this test, the researchers monitored the participants’ brains using diffusion tensor imaging. Diffusion tensor imaging maps white matter connections. While matter conducts signals through the brain.
The results indicate that there is a difference in the brain’s white matter activity when people process words based on meaning or based on sound. Semantics-focused readers had increased activity in areas that process meaning like the angular gyrus and the posterior cingulate. Phonetics-based readers had increased activity in areas that process sound like the superior temporal gyrus.
The different reading styles correspond to differences in thickness of connections between brain areas that process word sounds and meaning. According to Graves, “You don’t have to process a word’s meaning to read to aloud.” That is, there is more than one way to be a good reader. This concept could help researchers better understand dyslexia.
This research is published in the journal Brain and Language.
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