Mapping the human brain at The University of Auckland has revealed that abnormal brain activity appears to be the reason why some dyslexia sufferers find it difficult to learn to read.
The research team at the Department of Psychology in the Faculty of Science, headed by Dr Karen Waldie, is using functional magnetic resonance imaging (fMRI) to map the patterns of activity in the brains of normal readers and adults with dyslexia. The new study used the University's recently installed fMRI machine, the first of its type in New Zealand, to non-invasively monitor blood flow in the brain during specific reading tasks.
Dyslexia affects about seven percent of the New Zealand population and there is no known cure, although it is thought that greater understanding of the underlying neurological basis of the condition will assist in better diagnosis and management. Phonological dyslexia is the most prevalent, affecting about 70 per cent of children with reading difficulties caused by dyslexia. Children with phonological dyslexia are unable to decode written words phonetically - that is, associate sounds with letters - resulting in great difficulty reading unfamiliar and non-words.
The University of Auckland study showed mostly left hemisphere brain activity when normal readers were asked to perform three different reading tasks, including a phonics-based reading task where letter strings must be silently sounded-out to get the correct answer. In contrast, the dyslexic adults showed very limited left-brain activity during these tasks, with most activity being in the right brain.