Auditory and visual processing in children with dyslexia

Chapter 14 discusses learning and memory.  I wanted to look further into the learning disability dyslexia, which we also talked about in class.  Developmental dyslexia affects 5-10% of the population.  Dyslexia is a learning disability that impairs one's ability to read and also causes difficulties with writing as well.  It is thought to create these impairments by interfering with the ability to establish links between spoken sounds and written letters.  In this study, researchers were looking for possible sensory deficits in visual and auditory domains.  They wanted to assess sensory sensitivity in children with dyslexia and children without dyslexia.  They utilized two measures that have been used for this type of research before.  They used a frequency modulation detection task to check for auditory sensitivity by having the children listen to a pure-tone stimulus and a frequency-modulated stimulus.  The ability to detect small differences between tones indicates greater auditory processing sensitivity.  To test visual sensitivity, they used the global motion coherence task, which uses random dot kinematograms to measure sensitivity to dynamic changes in motion.  Researchers used a sample of 130 participants.  75 of the sample were children with dyslexia and 55 were normal readers.  The tests were done in phases.  Phase 1 was performed during the first month of the school year.  Phase 2 was performed 9 months later where the audtiory and visual measures were repeated.  Results indicated that for the auditory sensory processing measures, the children with dyslexia showed far less sensitivity than the control group.  In testing for visual sensitivity, they found that the children with dyslexia had reduced sensitivity to the global motion task as well.  However, there were some inconsistencies found between Phase 1 and Phase 2 of the sensory measures, and effects of temporal stability, maturation, and task demands may have contributed to these inconsistencies.  Overall, the findings of this study indicated that sensory deficits do exist in dyslexic children, but only in sub-groups of these children.  They believe that this could be a component of a wider deficit in accessing sensory representations within working memory.  This is a deficit that exists only in the phonological domain in many dyslexic children.  The researchers propose that future research be devoted to discovering why these auditory and visual sensitivity deficits occur only in sub-groups of dyslexic children.

Wright, C., & Conlon, E. (2009). Auditory and visual processing in children with dyslexia. Developmental Neuropsychology, 34(3), 330-355. Retrieved from EBSCOhost. doi:10.1080/87565640902801882