Orienting of visual attention in dyslexia: Evidence for asymmetric hemispheric control of attention

The control of attentional orienting was studied in children with specific reading disorder (SRD) or dyslexia, and it was compared with that of normal readers. We used the covert orienting paradigm to measure subjects' reaction times for target detection both in valid and invalid cue conditions, either in the left or in the right visual fields. In experiment 1, we investigated exogenous orienting. The cue consisted of a peripheral abrupt onset and the cue-target delay was 350 ms. As compared with normal readers, in dyslexics the cue effect was absent in the right visual field, whereas in the left visual field a greater cue effect was observed. No visual field asymmetry was found in normal readers. In experiment 2, we investigated endogenous orienting. The cue was shown centrally and the cue-target delay was 750 ms. In dyslexics and normal readers, orienting of attention was present in both visual fields. However, in the invalid condition, dyslexic children showed significantly slower r...