Evidence from sentence priming for an atypical language organisation in the brain of dyslexic males

The present study used an experimental paradigm that combined sentence priming, lexical decision, and visual hemifield stimulation to investigate the relationship between dyslexia and linguistic processing by the two hemispheres. It was predicted that left hemisphere (LH) superiority for word recognition in a constraining versus a neutral sentence context would be reduced, or even reversed in dyslexic as compared to normal participants. Because both dyslexia and LH superiority for language processing are considered to be more prevalent for males than for females, it was further expected that this decrease, or reversal, in LH superiority for word recognition in a sentence context would be more pronounced for males with dyslexia than for females with dyslexia. A total of 88 children, half of whom were females, participated in the study: 44 children were diagnosed as dyslexic and 44 were normal readers. The results generally confirmed the hypothesis and provided strong support for a reversal in hemispheric asymmetry in males with dyslexia. Implications for sentence processing of the excessive involvement of the right hemisphere (RH) in the dyslexia of males are discussed and the lexical-decision-sentence-priming paradigm is recommended as a promising means of exploring the issues related to these implications.