Bart Boets and fellow researchers at the Catholic University of Leuven in Belgium conducted a study to discover if they could actively see distorted neural patterns in the brains of dyslexics. For years leading up to this study, scientists thought dyslexia was simply caused by an inability to correctly learn phonetic representation, or “the way speech sounds are represented in the brain.” A child learns how to read and write by mastering the correspondence between phoneme—spoken sounds, and grapheme—written representations (i.e., letters and letter combinations) of spoken sounds. Boets’ study revealed contradictory results, suggesting that dyslexia is caused by a “disconnection syndrome” rather than distorted brain wiring.
The goal of this study was to measure the quality of phonetic representations in both the brains of dyslexics and average language learners, and observe the differences. As participants listened to speech sounds, Boets and his colleagues measured their bilateral auditory cortices activity using functional magnetic resonance imaging. The bilateral auditory cortex is where phonetic representations are initially hosted in the brain. To the researchers’ surprise, the phonetic representations were equally intact and distinct in this region for dyslexics and typical language learners. This means that dyslexics’ learning difficulties are not a result of degraded quality of phonetic representation abilities.
The researchers then observed high-level processing regions of the participants’ brains. They discovered that these higher level processing regions were not as active or robust as the bilateral auditory cortices in the brains of dyslexics. This lead researchers to determine that access to phonetic representation is hampered. These results of Boets’ study reveal that dyslexics’ brains have completely intact and robust phonetic representation abilities, but access to it is weakened, explaining why spoken language is not difficult for dyslexics, but written language—which requires more regions of the brain—is impaired. Bart Boets calls dyslexia a “disconnection syndrome”—a disability that stems from weakened access abilities to the region of the brain that hosts phonetic representation.
A NY Times article suggests then that because dyslexia is the result of impaired access to the correct phonetic information, working to strengthen that connection should be an active part of tutoring or therapy. Students who are dyslexic tend to read less, only affirming the weak connection between brain regions. If professionals and tutors work with the student to continue reading, they are actively working to strengthen those connections.
Visit BrainBalanceCenters.com to learn more about dyslexia as a “Disconnection Syndrome,” watch a video of Bart Boets explaining his research, or review the published study.