Atypical visual selective attention in children with dyslexia: evidence from N2pc and PD

Efficient visual attention is fundamental to the development of reading abilities. Previous studies have identified visual attention impairments in individuals with dyslexia, particularly in visual attention span and sluggish attention shifting. However, findings regarding basic visual selective attention remain controversial. To address this issue, the present study provides event-related potential (ERP) evidence to verify whether children with developmental dyslexia (DD) suffered from deficits in visual selective attention. A pop-out visual search task was used to examine visual attentional patterns to a lateral target in 66 children (33 children with DD and 33 typically developing (TD) children) using electroencephalography. Compared to TD children, children with DD showed a larger and prolonged P1 component, as well as a larger target-evoked N2-posterior contralateral (N2pc) component. The larger P1 amplitude was associated with lower reading fluency while the larger N2pc amplitude was associated with poor reading comprehension performance. Interestingly, children with DD were characterised by a larger target-elicited N2pc followed by a diminished distractor positivity (P_D) component, as well as a robust correlation between N2pc and P_D, compared to TD children. Children with DD show immature early attentional processing and may have an imbalance in the regulation of visual selective attention between attentional selection and suppression. Our findings provide ERP evidence for interpreting the underlying neural mechanism of visual selective attention in children with DD and may offer a new perspective for exploring the mechanism of visual attention deficits in dyslexia.