The cause of dyslexia may not be what we think they are, finds new research from Carnegie Mellon University (CMU). The researchers discovered that adults with dyslexia struggle with procedural learning, which involves acquiring skills and learning habits, as opposed to memorizing facts. The results indicate that procedural learning, particularly the ability to learn complex auditory categories is impaired in dyslexia. The finding could lead researchers to a deeper understanding of how dyslexia develops and to better interventions for the disorder.
The researchers constructed a study to test how procedural learning impacts the ability of people with dyslexia to learn sound categories. The study’s adult participants played a video game that had previously been shown to engage procedural learning of speech and non-speech sounds in adults without dyslexia. The game featured four types of aliens. Players had to determine whether aliens were friends or enemies based on how they looked, moved, and sounded. Each type of alien was associated with a category of complex, non-speech sounds. As the game progressed, players had to rely more on sound cues to help them identify which aliens were friendly.
In dyslexia, procedural learning of complex auditory categories is impaired. The participants with dyslexia performed significantly worse than the control group at learning the sound categories associated with different aliens in the game. They were also worse than controls at generalizing their learning to new sounds introduced after the game.
The results suggest that difficulties with processing speech could be a symptom of dyslexia—not the cause.
The researchers conclude that understanding how procedural learning and auditory skills interact in dyslexia could aid the development of more effective dyslexia interventions. “Auditory training has already shown promise in remediating phonological and reading skills in dyslexia. Understanding the nature of how procedural learning deficits interact with auditory category learning in dyslexia will direct evidence-based approaches to the next generation of dyslexia interventions,” stated study co-author Lori Holt, professor of psychology at CMU.
This research is published in the journal Cortex.
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