Does rapid auditory perception underlie the phonological awareness difficulties found in children with dyslexia?

Katrina Sheraton (Honours candidate)

Previous research has found that groups of individuals with dyslexia have performed worse than controls on tasks requiring rapid visual and auditory perception. The magnocellular deficit is one theory that has been proposed to explain such findings in the auditory and visual domain. This suggests that people with dyslexia may have a general deficit in "magnocellular" cells that are responsible for perception of transient and rapid stimuli in a variety of senses. However, there have been inconsistent results and large variations in scores found within groups with dyslexia on similar tasks. Children's wavering and inconsistent attention has been one variable found to confound previous studies in perception. In particular, it has been proposed that students that have difficulty with sustained and/or shifting attention have shown inferior performance on tasks of auditory perception and in reading.

To explore whether a "magnocellular deficit" may underlie poor phonemic awareness and word reading, I have combined measures of rapid auditory perception thresholds with stimuli varying in inter stimulus interval (ISI) and in frequency, with tasks measuring attention, memory and non-verbal IQ. After controlling for attention, memory and non-verbal IQ, I expect to find a relationship between rapid auditory perception and phonemic awareness that decreases as ISI and frequency increases. Alternatively, shifting and/or sustained attention may be a moderating factor in these results and be found to correlate highly with performance on rapid auditory perception, phonemic awareness and reading tasks.