(HealthDay News) – The size of a region of brain white matter known as the left arcuate fasciculus, which connects language regions of the brain, is associated with poor pre-reading skills in kindergarteners and an increased risk of dyslexia, according to a study published in the Aug. 14 issue of The Journal of Neuroscience.

Zeynep M. Saygin, PhD, from the Massachusetts Institute of Technology in Cambridge, and colleagues performed magnetic resonance imaging on 40 kindergartners who had been assessed for pre-reading skills and had received little or no reading instruction.

The researchers found a significant and positive correlation between the volume of the left arcuate fasciculus and higher composite scores of phonological awareness, the ability to identify and manipulate the sounds of language. The left arcuate fasciculus connects Broca’s area, which is involved in speech production, and Wernicke’s area, which is involved in understanding written and spoken language, according to the study.

“These findings indicate that the left arcuate fasciculus, which connects anterior and posterior language regions of the human brain, and which has been previously associated with reading ability in older individuals, is already smaller and has less integrity in kindergartners who are at risk for dyslexia because of poor phonological awareness,” Saygin and colleagues conclude.

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