Asymmetrical visual fields distribution of attention in dyslexic children: a neuropsychological study

Visual spatial attention was evaluated in dyslexic and normally reading children by using a flanker task. When an irrelevant distractor is presented adjacent to a target stimulus, interference is observed when the two stimuli are associated with conflicting responses. In the present study the distractor flanked the target either to the right or to the left. Results showed an asymmetric flanker effect in dyslexics, whereas it was symmetrical in normal readers. Dyslexics exhibited a reduced flanker effect in the left visual field, concomitant with a strong flanker effect in the right visual field. These results give further support to the hypothesized left-side minineglect in dyslexics. Data also provide evidence for a reduced ability in suppressing distracting information in the right visual field. Such visual field asymmetry is thought to play a crucial role in reading disorders. Right over-distractibility and left inattention suggest an impairment of the right parietal functions as supported by the magnocellular theory of dyslexia.